sometimes Aversion to the same thing as they think it will either be for their good or their hurt while that vicissitude of Appetites and Aversions remains in them they have that series of Thoughts which is called DELIBERATION which lasteth as long as they have it in their power to obtain that which pleaseth or to avoid that which displeaseth them Appetite therefore and Aversion are simply so called as long as they follow not Deliberation But if Deliberation have gone before then the last act of it if it be Appetite is called WILL if Aversion UNWILLINGNESSE so that the same thing is called both Will and Appetite but the consideration of them namely before and after Deliberation is divers Nor is that which is done within a Man whilest he Willeth any thing different from that which is done in other living Creatures whilest Deliberation having preceded they have Appetite Neither is the freedome of Willing or not willing greater in Man then in other living Creatures For where there is Appetite the entire cause of Appetite hath preceded and consequently the act of Appetite could not choose but follow that is hath of necessity followed as is shewn Chapt. 9th Article 5. And therefore such a Liberty as is free from Necessity is not to be found in the Will either of Men or Beasts But if by Liberty we understand the faculty or power not of Willing but of Doing what they Will then certainly that Liberty is to be allowed to both and both may equally have it whensover it is to be had Again when Appetite and Aversion do with celerity succeed one another the whole series made by them hath its name sometimes from one sometimes from the other For the same Deliberation whilest it inclines sometimes to one sometimes to the other is from Appetite called HOPE and from Aversion FEAR For where there is no Hope it is not to be called Fear but HATE and where no Fear not Hope but DESIRE To conclude all the Passions called Passions of the Minde consist of Appetite and Aversion except pure Pleasure and Pain which are a certain Fruition of good or Evil as Anger is Aversion from some imminent evil but such as is joyned with Appetite of avoiding that evil by force But because the Passions and Perturbations of the Minde are innumerable and many of them not to be discerned in any Creatures besides Men I will speak of them more at large in that Section which is concerning Man As for those Objects if there be any such which do not at all stir the Mind we are said to Contemn them And thus much of Sense in general In the next place I shall speak of Sensible Objects CHAP. XXVI Of the World and of the Starres 1 The Magnitude and Duration of the World inscrutable 2 No place in the World Empty 3 The arguments of Lucretius for Vacuum invalid 4 Other arguments for the establishing of Vacuum invalid 5 Six suppositions for the salving of the Phaenomena of Nature 6 Possible causes of the Motions Annual and Diurnal and of the apparent Direction Station and Retrogradation of the Planets 7 The supposition of Simple Motion why likely 8 The cause of the Excentricity of the annual motion of the Earth 9 The cause why the Moon hath alwayes one and the same face turned towards the Earth 10 The cause of the Tides of the Ocean 11 The cause of the Praecession of the Equinoxes 1 COnsequent to the Contemplation of Sense is the contemplation of Bodies which are the efficient causes or Objects of Sense Now every Object is either a part of the whole World or an Aggregate of parts The greatest of all Bodies or sensible Objects is the World it self which we behold when we look round about us from this point of the same which we call the Earth Concerning the World as it is one Aggregate of many parts the things that fall under inquiry are but few and those we can determine none Of the whole World we may inquire what is its Magnitude what its Duration and how many there be but nothing else For as for Place and Time that is to say Magnitude and Duration they are only our own fancies of a Body simply so called that is to say of a Body indefinitely taken as I have shewne before in the 7 chapter All other Phantasmes are of Bodies or Objects as they are distinguished from one another as Colour the Phantasme of coloured Bodies Sound of Bodies that move the Sense of Hearing c. The questions concerning the Magnitude of the World are whether it be Finite or Infinite Full or not Full Concerning its Duration whether it had a Beginning or be Eternall and concerning the number whether there be One or Many though as concerning the Number if it were of infinite Magnitude there could be no controversy at all Also if it had a beginning then by what Cause and of what Matter it was made and againe from whence that Cause and that Matter had their being will be new questions till at last we come to one or many eternall Cause or Causes And the determination of all these things belongeth to him that professeth the universal doctrine of Philosophy in case as much could be known as can be sought But the knowledge of what is Infinite can never be attained by a finite Inquirer Whatsoever we know that are Men we learn it from our Phantasmes and of Infinite whether Magnitude or Time there is no Phantasme at all so that it is impossible either for a man or any other creature to have any conception of Infinite And though a man may from some Effect proceed to the immediate Cause thereof frō that to a more remote Cause and so ascend continually by right ratiocination from Cause to Cause yet he will not be able to proceed eternally but wearied will at last give over without knowing whether it were possible for him to proceed to an end or not But whether we suppose the World to be Finite or Infinite no absurdity will follow For the same things which now appear might appear whether the Creator had pleased it should be Finite or Infinite Besides though from this that nothing can move it self it may rightly be inferred that there was some first eternal Movent yet it can never be inferred though some use to make such inference that that Movent was eternally Immoveable but rather eternally Moved For as it is true that nothing is moved by it self so it is true also that nothing is moved but by that which is already moved The questions therefore about the Magnitude and Beginning of the World are not to be determined by Philosophers but by those that are lawfully authorised to order the Worship of God For as Almighty God when he had brought his People into Judaea allowed the Priests the first fruits reserved to himself so when he had delivered up the World to the disputations of Men it was his pleasure that
as Water 8 Another cause of Hardness from the fuller contact of Atomes Also how Hard things are broken 9 A third cause of Hardness from Heat 10 A fourth cause of Hardness from the motion of Atomes enclosed in a narrow space 11 How Hard things are Softned 12 Whence proceeds the spontaneous Restitution of things Bent. 13 Diaphanous and Opacous what they are and whence 14 The cause of Lightning and Thunder 15 Whence it proceeds that Clouds can fall again after they are once elevated and frozen 16 How it could be that the Moon was eclipsed when she was not diametrally opposite to the Sunne 17 By what means many Sunnes may appear at once 18 Of the Heads of Rivers 1 AS when the motion of the ambient aethereal substance makes the Spirits and fluid parts of our Bodies tend outwards we acknowledge Heat so by the endeavour inwards of the same spirits and humours we feel Cold. So that to Cool is to make the exterior parts of the Body endeavour inwards by a motion contrary to that of Calefaction by which the internal parts are called outwards He therefore that would know the cause of Cold must find by what motion or motions the exterior parts of any Body endeavour to retire inwards To begin with those Phaenomena which are the most familiar There is almost no man but knows that breath blown strongly and which comes from the mouth with violence that is to say the passage being straight will Cool the hand and that the same breath blown gently that is to say through a greater aperture wil warm the same The cause of which Phaenomenon may be this The breath going out hath two motiōs the one of the whole and direct by which the formost parts of the hand are driven inwards the other simple motion of the small particles of the same breath which as I have shewn in the 3d Article of the last Chapter causeth Heat According therefore as either of these Motions is predominant so there is the sense sometimes of Cold sometimes of Heat Wherefore when the breath is softly breathed out at a large passage that simple Motion which causeth Heat prevaileth and consequently Heat is felt and when by compressing the lips the breath is more strongly blown out then is the direct motion prevalent which makes us feel Cold. For the direct motion of the breath or aire is Wind and all Wind Cools or diminisheth former heat 2 And seeing not onely great Wind but almost any Ventilation and stirring of the Aire doth refrigerate the reason of many experiments concerning Cold cannot well be given without finding first what are the causes of Wind. Now Wind is nothing else but the direct motion of the Aire thrust forwards which nevertheless when many Winds concurre may be circular or otherwise indirect as it is in Whirle-winds Wherefore in the first place we are to enquire into the Causes of Winds Wind is Aire moved in a considerable quantity and that either in the manner of Waves which is both forwards also up down or else forwards onely Supposing therefore the Aire both cleer and calm for any time how little soever yet the greater Bodies of the World being so disposed and ordered as has been said it will be necessary that a Wind presently arise some where For seeing that motion of the parts of the Aire which is made by the Simple Motion of the Sunne in his own Epicycle causeth an exhalation of the particles of water from the Seas and all other moist Bodies and those particles make Clouds it must needs follow that whilest the particles of water pass upwards the particles of Aire for the keeping of all Spaces full be justled out on every side and urge the next particles and these the next till having made their circuit there comes continually so much Aire to the hinder parts of the Earth as there went water from before it Wherefore the ascending Vapours move the Aire towards the sides every way and all direct motion of the Aire being Wind they make a Wind. And if this Wind meet often with other Vapours which arise in other places it is manifest that the force thereof will be augmented the way or course of it changed Besides according as the Earth by its diurnal motion turns sometimes the drier sometimes the moister part towards the Sunne so sometimes a greater sometimes a less quantity of Vapours will be raised that is to say sometimes there will be a less sometimes a greater Wind. Wherefore I have rendred a possible cause of such Winds as are generated by Vapours and also of their Inconstancy From hence it follows that these Winds cannot be made in any place which is higher then that to which Vapours may ascend Nor is that incredible which is reported of the highest Mountains as the Pique of Tenariffe and the Andes of Peru namely that they are not at all troubled with these inconstant Winds And if it were certain that neither Rain nor Snow were ever seen in the highest tops of those Mountains it could not be doubted but that they are higher then any place to which Vapours use to ascend 3 Nevertheless there may be Wind there though not that which is made by the ascent of Vapours yet a less more constant Wind like the continued blast of a pair of bellows blowing from the East And this may have a double cause the one the diurnal mo tion of the Earth the other its simple motion in its own Epicycle For these Mountains being by reason of their height more eminent then all the rest of the parts of the Earth do by both these Motions drive the Aire from the West Eastwards To which though the diurnal Motion contribute but little yet seeing I have supposed that the simple Motion of the Earth in its own Epicycle makes two revolutions in the same time in which the diurnal Motion makes but one and that the Semidiameter of the Epicycle is double to the Semidiameter of the diurnal Conversion the Motion of every point of the Earth in its own Epicycle will have its velocity quadruple to that of the diurnal Motion so that by both these Motions together the tops of those Hils will sensibly be moved against the Aire and consequently a Wind will be felt For whether the Air strike the Sentient or the Sentient the Air the perception of Motion will be the same But this Wind seeing it is not caused by the ascent of Vapours must necessarily be very Constant. 4 When one Cloud is already ascended into the Aire if another Cloud ascend towards it that part of the Aire which is intercepted between them both must of necessity be pressed out every way Also when both of them whilest the one ascends and the other either stayes or descends come to be joyned in such manner as that the aethereal substance be shut within them on every side it will by this compression also go out by penetrating the Water
the Names of the parts of any Speech be explicated is it not necessary that the Definition should be a Name Compounded of them For example when these Names Aequilaterall Quadrilaterall Right-angled are sufficiently understood it is not necessary in Geometry that there should be at all such a Name as Square for defined Names are received in Philosophy for brevities sake onely Fiftly That Compounded Names which are defined one way in some one part of Philosophy may in another part of the same be otherwise defined as a Parabola and an Hyperbole have one Definition in Geometry and another in Rhetorique for Definitions are instituted and serve for the understanding of the Doctrine which is treated of And therefore as in one part of Philosophy a Definition may have in it some one fit Name for the more briefe explanation of some proposition in Geometry so it may have the same liberty in other parts of Philosophy for the use of Names is particular even where many agree to the setling of them and arbitrary Sixtly That no Name can be defined by any one Word because no one Word is sufficient for the Resolving of one or more words Seventhly That a defined Name ought not to be repeated in the Definition For a defined Name is the whole Compound and a Definition is the Resolution of that Compound into parts but no Totall can be part of it selfe 16 Any two Definitions that may be compounded into a Syllogisme produce a Conclusion which because it is derived from Principles that is from Definitions is said to be Demonstrated and the Derivation or Composition it selfe is called a Demonstration In like manner if a Syllogisme be made of two Propositions whereof one is a Definition the other a Demonstrated Conclusion or neither of them is a Definition but both formerly demonstrated that Syllogisme is also called a Demonstration and so successively The Definition therefore of a Demonstration is this A DEMONSTRATION is a Syllogism or Series of Syllogisms derived and continued from the Definitions of Names to the last Conclusion And from hence it may be understood that all true Ratiocination which taketh its beginning from true Principles produceth Science and is true Demonstration For as for the Originall of the Name although that which the Greeks called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and the Latines Demonstratio was understood by them for that sort onely of Ratiocination in which by the describing of certaine Lines and Figures they placed the thing they were to prove as it were before mens Eyes which is properly 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 or to shew by the Figure yet they seem to have done it for this reason that unlesse it were in Geometry in which only there is place for such Figures there was no Ratiocination certaine and ending in Science their Doctrines concerning all other things being nothing but Controversie and Clamour which neverthelesse hapned not because the Truth to which they pretended could not be made evident without Figures but because they wanted true Principles from which they might derive their Ratiocination and therefore there is no reason but that if true Definitions were praemised in all sorts of Doctrines the Demonstrations also would be true 17 It is proper to Methodical Demonstration First That there be a true Succession of one Reason to another according to the Rules of Syllogizing delivered above Secondly That the Praemisses of all Syllogismes be demonstrated from the first Definitions Thirdly That after Definitions he that Teaches or Demonstrates any thing proceed in the same Method by which he found it out namely that in the first place those things be demonstrated which immediately succeed to Universal Definitions in which is contained that part of Philosophy which is called Philosophia Prima Next those things which may be demonstrated by Simple Motion in which Geometry consists After Geome try such things as may be taught or shewed by manifest Action that is by Thrusting from or Pulling towards And after these the Motion or Mutation of the invisible parts of Things and the Doctrine of Sense Imagination of the internal Passions especially those of Men in which are comprehended the Grounds of Civil Duties or Civil Philosophy which takes up the last place And that this Method ought to be kept in all sorts of Philosophy is evident from hence that such things as I have said are to be taught last cannot be demonstrated till such as are propounded to be first treated of be fully understood Of which Method no other Example can be given but that Treatise of the Elements of Philosophy which I shall begin in the next Chapter and continue to the end of the worke 18 Besides those Paralogismes whose fault lies either in the Falsity of the Praemisses or the want of true Composition of which I have spoken in the praecedent Chapter there are two more which are frequent in Demonstration one whereof is commonly called Petitio Principii the other is the supposing of a False Cause and these do not onely deceive Unskilfull Learners but sometimes Masters themselves by making them take that for well demonstrated which is not demonstrated at all Petitio Principii is when the Conclusion to be proved is disguised in other Words and put for the Definition or Principle from whence it is to be demonstrated and thus by putting for the Cause of the Thing sought either the Thing it selfe or some Effect of it they make a Circle in their Demonstration As for example He that would Demonstrate that the Earth stands still in the Center of the World and should suppose the Earths Gravity to be the Cause thereof and define Gravity to be a quality by which every heavy Body tends towards the Center of the World would lose his labour for the question is What is the Cause of that quality in the Earth and therefore he that supposes Gravity to be the Cause puts the Thing it selfe for its own Cause Of a False Cause I find this example in a certaine Treatise where the thing to be demonstrated is the Motion of the Earth He begins therefore with this that seeing the Earth and the Sun are not alwayes in the same scituation it must needs be that one of them be locally moved which is true next he affirms that the Vapours which the Sun raises from the Earth and Sea are by reason of this Motion necessarily moved which also is true from whence he infers the Winds are made and this may passe for granted and by these Winds he sayes the Waters of the Sea are moved and by their Motion the bottome of the Sea as if it were beaten forwards moves round and let this also be granted wherefore he concludes the Earth is moved which is neverthelesse is a Paralogisme For if that wind were the Cause why the Earth was from the beginning moved round and the Motion either of the Sunne or the Earth were the Cause of that Wind then the Motion of the Sunne or
not upon our Thought we say is a thing subsisting of itself as also existing because without Us and lastly it is called the Subject because it is so placed in and subjected to Imaginary Space that it may be understood by Reason as well as perceived by Sense The Definition therefore of Body may be this A BODY is that which having no dependance upon our Thought is coincident or coextended with some part of Space 2 But what an Accident is cannot so easily be explained by any Definition as by Examples Let us imagine therefore that a Body fills any Space or is coextended with it that Coextention is not the coextended Body And in like manner let us imagine that the same Body is removed out of its place that Removing is not the removed Body Or let us think the same not removed that notremoving or Rest is not the resting Body What then are these things They are Accidents of that Body But the thing in question is What is an Accident which is an Enquiry after that which we know already and not that which we should enquire after For who does not alwayes and in the same manner understand him that sayes any thing is Extended or Moved or not Moved But most men will have it be said that an Accident is something namely some part of a natural thing when indeed it is no part of the same To satisfie these men as well as may be they answer best that define an Accident to be the Manner by which any Body is conceived which is all one as if they should say An Accident is that faculty of any Body by which it works in us a Conception of itself Which Definition though it be not an Answer to the Question propounded yet it is an Answer to that Question which should have been propounded namely whence does it happen that one part of any Body appears here another part there For this is well answered thus It happens from the Extension of that Body Or How comes it to pass that the whole Body by succession is seen now here now there and the answer will be By reason of its Motion Or lastly Whence is it that any Body possesseth the same space for sometime And the answer will be because it is not moved For if concerning the Name of a Body that is concerning a Concrete Name it be asked what is it the answer must be made by Definition for the Question is concerning the signification of the Name But if it be asked concerning an Abstract Name what is it the Cause is demanded why a thing appears so or so As if it be asked what is Hard The Answer will be Hard is that whereof no Part gives place but when the Whole gives place But if it be demanded what is Hardness A Cause must be shewn why a Part does not give place except the Whole give place Wherefore I define an ACCIDENT to be the Maâ—ner of our conception of Body 3 When an Accident is said to be in a Body it is not so to be understood as if any thing were conteined in that Body as if for example Redness were in Blood in the same manner as Blood is in a bloody cloth that is as a Part in the Whole for so an Accident would be a Body also But as Magnitude or Rest or Motion is in that which is Great or which Resteth or which is Moved which how it is to be understood every man understands so also it is to be understood that every other Accident is in its Subject And this also is explicated by Aristotle no otherwise then negatively namely that An Accident is in its Subject not as any part thereof but so as that it may be away the Subject still remaining which is right saving that there are certain Accidents which can never perish except the Body perish also for no Body can be conceived to be without Extension or without Figure All other Accidents which are not common to all Bodies but peculiar to some onely as To be at Rest to be Moved Colour Hardness and the like do perish continually and are succeeded by others yet so as that the Body never perisheth And as for the opinion that some may have that all other Accidents are not in their Bodies in the same manner that Extension Motion Rest or Figure are in the same for example that Colour Heat Odour Vertue Vice and the like are otherwise in them and as they say inherent I desire they would suspend their judgement for the present and expect a little till it be found out by Ratiocination whether these very Accidents are not also certain Motions either of the Mind of the perceiver or of the Bodies themselves which are perceived for in the search of this a great part of Naturall Philosophy consists 4 The Extension of a Body is the same thing with the MAGNITUDE of it or that which some call Real Space But this Magnitude does not depend upon our Cogitation as Imaginary Space doth for this is an Effect of our Imagination but Magnitude is the Cause of it this is an Accident of the Mind that of a Body existing out of the Mind 5 That Space by which word I here understand Imaginary Space which is coincident with the Magnitude of any Body is called the PLACE of that Body and the Body it self is that which we call the Thing Placed Now Place and the Magnitude of the Thing Placed differ First in this that a Body keeps alwayes the same Magnitude both when it is at Rest and when it is Moved but when it is Moved it does not keep the same Place Secondly in this that Place is a Phantasme of any Body of such and such Quantity and Figure but Magnitude is the peculiar Accident of every Body for one Body may at several times have several Places but has always one and the same Magnitude Thirdly in this that Place is nothing out of the Mind nor Magnitude any thing within it And lastly Place is feigned Extension but Magnitude true Extension and a Placed Body is not Extension but a Thing Extended Besides Place is Immoveable for seeing that which is Moved is understood to be carried from Place to Place if Place were Moved it would also be carried from Place to Place so that one Place must have another Place and that Place another Place and so on infinitely which is ridiculous And as for those that by making Place to be of the same Nature with Real Space would from thence maintain it to be Immoveable they also make Place though they do not perceive they make it so to be a meer Phantasme For whilest One affirms that Place is therefore said to be Immoveable because Space in general is considered there if he had remembred that nothing is General or Universal besides Names or Signes he would easily have seen that that Space which he sayes is considered in general is nothing but a Phantasme in the Mind or
other then an Efficient Cause A Final Cause has no place but in such things as have Sense and Will and this also I shall prove hereafter to be an Efficient Cause CHAP. XI Of Identity and Difference 1 What it is for one thing to Differ from another 2 To Differ in Number Magnitude Species and Genus what 3 What is Relation Proportion and Relatives 4 Proportionals what 5 The Proportion of Magnitudes to one another wherein it consists 6 Relation is no new Accident but one of those that were in the Relative before the Relation or Comparison was made Also the Causes of Accidents in the Correlatives are the Cause of Relation 7 Of the Beginning of Individuation 1_HItherto I have spoken of Body simply and of Accidents common to all Bodies as Magnitude Motion Rest Action Passion Power Possible c. And I should now descend to those Accidents by which one Body is distinguished from anoâ—â—er but that it is first to be declared what it is to be Distinct and not Distinct namely what are the SAME and DIFFERENT for this also is common to all Bodies that they may be distinguished and differenced from one another Now two Bodies are said to Differ from one another when something may be said of one of them which cannot be said of the other at the same time 2 And first of all it is manifest that no Two Bodies are the Same for seeing they are Two they are in two places at the same time as that which is the Same is at the same time in one and the same place All Bodies therefore differ from one another in Number namely as One and Another so that the Same and different in Number are Names opposed to one another by Contradiction In Magnitude Bodies differ when One is greater then Another as a Cubit long and two Cubits long of two pound weight and of three pound weight And to these Equals are opposed Bodies which differ more then in Magnitude are called Unlike and those which differ onely in Magnitude Like Also of Unlike Bodies some are said to differ in the Species other in the Genus in the Species when their difference is perceived by one and the same Sense as White and Black and in the Genus when their difference is not perceived but by divers Senses as White and Hot. 3 And the Likeness or Unlikeness Equality or Inequality of one Body to another is called their RELATION and the Bodies themselves Relatives or Correlatives Aristotle calls them 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 the first whereof is usually named the Antecedent and the second the Consequent and the Relation of the Antecedent to the Consequent according to Magnitude namely the Equality the Excess or Defect thereof is called the PROPORTION of the Antecedent to the Consequent so that Proportion is nothing but the Equality or Inequality of the Magnitude of the Antecedent compared to the Magnitude of the Consequent by their difference only or compared also with their difference For Example the Proportion of Three to Two consists only in this that Three exceeds Two by Unity and the Proportion of Two to Five in this that Two compared with Five is deficient of it by Three either simply or compared with the numbers different and therefore in the Proportion of Unequals the Proportion of the Lesse to the Greater is called DEFECT and that of the Greater to the Lesse EXCESS 4 Besides of Unequals some are more some lesse and some equally unequall so that there is Proportion of Proportions as well as of Magnitudes namely where two Unequals have relation to two other Unequals as when the Inequality which is between 2 and 3 is compared with the Inequality which is between 4 and 5. In which Comparison there are alwayes four Magnitudes or which is all one if there be but three the midlemost is twice numbred and if the Proportion of the first to the second be equal to the Proportion of the third to the fourth then the four are said to be Proportionals otherwise they are not Proportionals 5 The Proportion of the Antecedent to the Consequent consists in their Difference not onely simply taken but also as compared with one of the Relatives that is either in that part of the greater by which it exceeds the lesse or in the Remainder after the lesse is taken out of the greater as the Proportion of Two to Five consists in the Three by which Five exceeds Two not in Three simply onely but also as compared with Five or Two For though there be the same difference between Two Five which is between Nine and Twelve namely Three yet there is not the same Inequality and therefore the Proportion of Two to Five is not in all Relation the same with that of Nine to Twelve but onely in that which is called Arithmetical 6 But we must not so think of Relation as if it were an Accident differing from all the other Accidents of the Relative but one of them namely that by which the Comparison is made For example the likeness of one White to another White or its Unlikeness to Black is the same Accident with its Whiteness and Equality and Inequality the same Accident with the Magnitude of the thing compared though under another Name for that which is called White or Great when it is not compared with something else the same when it is compared is called Like or Unlike Equal or Unequal And from this it follows that the Causes of the Accidents which are in Relatives are the Causes also of Likeness Unlikeness Equality and Inequality namely that he that makes two Unequal Bodies makes also their Inequality and he that makes a Rule and an Action makes also if the Action be congruous to the Rule their Congruity if Incongruous their Incongruity And thus much concerning Comparison of one Body with another 7 But the same Body may at different times be Compared with it self And from hence springs a great controversie among Philosophers about the Beginning of Individuation namely in what sense it may be conceived that a Body is at one time the same at another time not the same it was formerly For example whether a Man grown old be the same Man he was whilest he was young or another Man or whether a City be in different Ages the same or another City Some place Individuity in the Unity of Matter others in the Unity of Form and one sayes it consists in the Unity of the Aggregate of all the Accidents together For Matter it is pleaded that a lump of Wax whether it be Spherical or Cubical is the same Wax because the same Matter For Form that when a Man is grown from an Infant to be an Old Man though his Matter be changed yet he is still the same Numerical Man for that Identity which cannot be attributed to the Matter ought probably to be ascribed to the Form For the Aggregate of Accidents no Instance can be made but because
nothing but perturbed Light is comprehended Wherefore the Phantasme of a Lucid Body is Light and of a coloured Body Colour But the Object of Sight properly so called is neither Light nor Colour but the Body itself which is lucid or enlightned or coloured For Light and Colour being Phantasmes of the Sentient cannot be Accidents of the Object Which is manifest enough from this that Visible things appear oftentimes in places in which we know assuredly they are not and that in different places they are of different colours and may at one and the same time appear in divers places Motion Rest Magnitude and Figure are common both to the Sight and Touch and the whole appearance together of Figure and Light or Colour is by the Greeks commonly called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and by the Latines Species and Imago all which names signifie no more but Appearance The phantasme which is made by Hearing is Sound by Smell Odour by Tast Savour and by Touch Hardness and Softness Heat and Cold Wetness Oiliness and many more which are easier to be distinguished by sense then words Smoothness Roughness Rarity and Density refer to Figure and are therefore common both to Touch and Sight And as for the Objects of Hearing Smel Tast and Touch they are not Sound Odour Savour Hardness c. but the Bodies themselves from which Sound Odour Savour Hardness c. proceed Of the causes of which and of the manner how they are produced I shall speak hereafter But these Phantasmes though they be effects in the Sentient as Subject produced by Objects working upon the Organs yet there are also other effects besides these produced by the same Objects in the same Organs namely certain Motions proceeding from Sense which are called Animal Motions For seeing in all Sense of external things there is mutual Action and Reaction that is two Endeavours opposing one another it is manifest that the motion of both of them together will be continued every way especially to the confines of both the Bodies And when this happens in the internal Organ the Endeavour outwards will proceed in a solid Angle which will be greater and consequently the Idea greater then it would have been if the impression had been weaker 11 From hence the Natural cause is manifest First why those things seem to be greater which caeteris paribus are seen in a greater Angle Secondly why in a serene cold night when the Moon doth not shine more of the fixed Stars appear then at another time For their action is less hindred by the serenity of the Aire and not obscured by the greater Light of the Moon which is then absent and the Cold making the Air more pressing helpeth or strengtheneth the action of the Stars upon our Eies in so much as Stars may then be seen which are seen at no other time And this may suffice to be said in general concerning Sense made by the Reaction of the Organ For as for the place of the Image the deceptions of Sight and other things of which we have experience in our selves by Sense being they depend for the most part upon the Fabrick it self of the Eie of Man I shall speak of them then when I come to speak of Man 12 But there is another kind of Sense of which I will say somthing in this place namely the Sense of Pleasure and Pain proceeding not from the Reaction of the Heart outwards but from continual action from the outermost part of the Organ towards the Heart For the original of Life being in the Heart that motion in the Sentient which is propagated to the Heart must necessarily make some alteration or diversion of Vital Motion namely by quickning or slackening helping or hindering the same Now when it helpeth it is Pleasure and when it hindereth it is Pain Trouble Grief c. And as Phantasmes seem to be without by reason of the Endeavour outwards so Pleasure and Pain by reason of the Endeavour of the Organ inwards seem to be within namely there where the first Cause of the Pleasure or Pain is as when the Pain proceeds from a Wound we think the Pain and the Wound are both in the same place Now Vital Motion is the Motion of the Bloud perpetually circulating as hath been shewn from many infallible signes and marks by Doctor Harvey the first Observer of it in the Veins and Arteries Which Motion when it is hindered by some other Motion made by the action of sensible Objects may be restored again either by bending or setting straight the parts of the Body which is done when the Spirits are carried now into these now into other Nerves till the Pain as farre as is possible be quite taken away But if Vital Motion be helped by Motion made by Sense then the parts of the Organ will be disposed to guide the Spirits in such manner as conduceth most to the preservation and augmentation of that motion by the help of the Nerves And in animal motion this is the very first Endeavour and found even in the Embrio which while it is in the wombe moveth its limbes with voluntary motion for the avoiding of whatsoever troubleth it or for the pursuing of what pleaseth it And this first Endeavour when it tends towards such things as are known by experience to be pleasant is called APPETITE that is an Approaching and when it shuns what is troublesome AVERSION or Flying from it And little Infants at the beginning and as soon as they are born have appetite to very few things as also they avoid very few by reason of their want of Experience and Memory therefore they have not so great a variety of animal Motion as we see in those that are more grown For it is not possible without such knowledge as is derived from Sense that is without Experience and Memory to know what will prove pleasant or hurtful onely there is some place for conjecture from the looks or aspects of things And hence it is that though they do not know what may do them good or harm yet sometimes they approach and sometimes retire from the same thing as their doubt prompts them But afterwards by accustoming themselves by little and little they come to know readily what is to be pursued and what to be avoided and also to have a ready use of their Nerves and other Organs in the pursuing and avoiding of good and bad Wherefore Appetite and Aversion are the first Endeavours of Animal Motion Consequent to this first Endeavour is the Impulsion into the Nerves and Retraction again of Animal Spirits of which it is necessary there be some Receptacle on place neer the original of the Nerves and this Motion or Endeavour is followed by a swelling and Relaxation of the Muscles and lastly these are followed by Contraction and Extension of the limbes which is Animal Motion 13 The Considerations of Appetites and Aversions are divers For seeing Living Creatures have sometimes Appetite and
the midst of the Heaven 15 The cause of Whiteness 16 The cause of Blackness 1 BEsides the Starres of which I have spoken in the last Chapt. whatsoever other Bodies there be in the World they may be all comprehended under the name of Intersidereal Bodies And these I have already supposed to be either the most fluid Aether or such Bodies whose parts have some degree of cohaesion Now these differ from one another in their several Consistencies Magnitudes Motions and Figures In Consistency I suppose some Bodies to be Harder others Softer through all the several degrees of Tenacity In Magnitude some to be Greater others Less and many unspeakably Little For we must remember that by the Understanding Quantity is divisible into divisibles perpetually And therefore if a man could do as much with his hands as he can with his Understanding he would be able to take from any given magnitude a part which should be less then any other magnitude given But the Omnipotent Creator of the World can actually from a part of any thing take another parâ— as farre as we by our Understanding can conceive the same to be divisible Wherefore there is no impossible Smalness of Bodies And what hinders but that we may think this likely For we know there are some living Creatures so small that we can scarce see their whole Bodies Yet even these have their young ones their little Veins and other Vessels and their Eyes so smal as that no Microscope can make them visible So that we cannot suppose any magnitude so little but that our very supposition is actually exceeded by Nature Besides there are now such Microscopes commonly made that the things we see with them appear a hundred thousand times bigger then they would do if we looked upon them with our bare Eyes Nor is there any doubt but that by augmenting the power of these Microscopes for it may be augmented as long as neither Matter nor the hands of Workmen are wanting every one of those hundred thousandth parts might yet appear a hundred thousand times geater then they did before Neither is the Smalness of some Bodies to be more admired then the vast Greatness of others For it belongs to the same infinite Power as well to augment infinitely as infinitely to diminish To make the great Orbe namely that whose Radius reacheth from the Earth to the Sunne but as a point in respect of the distance between the Sunne and the fixed Starres and on the contrary to make a Body so little as to be in the same proportion less then any other visible Body proceeds equally from one and the same Authour of Nature But this of the immense distance of the fixed Starres which for a long time was accounted an incredible thing is now believed by almost all the Learned Why then should not that other of the smalness of some Bodies become credible at some time or other For the Majesty of God appears no less in small things then in great and as it exceedeth humane sense in the immense greatness of the Universe so also it doth in the smalness of the parts thereof Nor are the first Elements of Compositions nor the first Beginnings of Actions nor the first Moments of Times more credible then that which is now believed of the vast distance of the fixed Starres Some things are acknowledged by mortal men to be very Great though Finite as seeing them to be such They acknowledge also that some things which they do not see may be of infinite magnitude But they are not presently nor without great study perswaded that there is any Mean between Infinite the Greatest of those things which either they see or imagine Nevertheless when after meditation contemplation many things which we wondred at before are now grown more familiar to us we then believe them and transferre our admiration from the Creatures to the Creator But how little soever some Bodies may be yet I will not suppose their quantity to be less then is requisite for the salving of the Phaenomena And in like manner I shall suppose their motion namely their Velocity and Slowness and the Variety of their Figures to be onely such as the explication of their natural causes requires And lastly I suppose that the parts of the pure Aether as if it were the First Matter have no motion at all but what they receive from Bodies which float in them and are not themselves fluid 2 Having laid these Grounds let us come to speake of Causes and in the first place let us inquire what may be the cause of the Light of the Sunne Seeing therefore the Body of the Sunne doth by its simple circular motion thrust away the ambient aethereall substance sometimes one way sometimes another so that those parts which are next the Sunne being moved by it doe propagate that motion to the next remote parts and these to the next and so on continually it must needs be that notwithstanding any distance the foremost part of the Eie will at last be pressed and by the pressure of that part the motion will be propagated to the innermost part of the Organ of Sight namely to the Heart and from the reaction of the Heart there will proceed an endeavour back by the same way ending in the endeavour outwards of the Coat of the Eie called the Retina But this endeavour outwards as has been defined in the 25 chapter is the thing which is called Light or the Phantasme of a Lucid Body For it is by reason of this Phantasme that an Object is called Lucid. Wherefore we have a possible cause of the Light of the Sunne which I undertook to find 3 The generation of the Light of the Sunne is accompanied with the generation of Heat Now every man knowes what Heat is in himselfe by feeling it when he growes Hot but what it is in other things he knowes onely by ratiocination For it is one thing to grow Hot and another thing to Heat or make Hot. And therefore though we perceive that the Fire or the Sunne Heateth yet we doe not perceive that it is it selfe Hot. That other living creatures whilest they make other things Hot are Hot themselves we inferre by reasoning from the like sense in our selves But this is not a necessary inference For though it may truly be said of living Creatures that They Heat therefore they are themselves Hot yet it cannot from hence be truly inferred that Fire Heateth therefore it is it selfe Hot no more then this Fire causeth Pain therefore it is it self in Pain Wherefore that is onely and properly called Hot which when we feel we are necessarily Hot. Now when we grow Hot we find that our Spirits and Blood and whatsoever is fluid within us is called out from the internall to the externall parts of our Bodies more or lesse according to the degree of the Heat and that our Skin swelleth He therefore that can give a possible cause
Metaphysical Empusa not by skirmish but by letting in the light upon her For I am confident if any confidence of a Writing can proceed from the Writers fear circumspection diffidence that in the three former parts of this Book all that I have said is sufficiently demonstrated from Definitions all in the fourth part from Suppositions not absurd But if there appear to your Lordship any thing less fully demonstrated then to satisfie every Reader the cause was this that I professed to write not all to all but some things to Geometricians onely But that your Lordship will be satisfied J cannot doubt There remains the second Section which is concerning Man That part thereof where J handle the Optiques contayning six Chapters together with the Tables of the Figures belonging to them I have already written engravenlying by me above these six years The rest shall as soon as J can be added to it though by the contumelies petty injuries of some unskilful men I know already by experience how much greater thanks will be due then payed me for telling Men the truth of what Men are But the burthen I have taken on me I mean to carry through not striving to appease but rather to revenge my self of Envy by encreasing it For it contents me that I have your Lordships favour which being all you require J acknowledge and for which with my prayers to Almighty God for your Lordships safety J shall to my power be always thankefull London April 23 1655. YOUR LORDSHIPS most humble Servant Thomas Hobbes The Authors Epistle To the Reader THink not courteous Reader that the Philosophy the Elements whereof I am going to set in order is that which makes Philosophers Stones nor that which is found in the Metaphsique Codes But that it is the Natural Reason of Man busily flying up and down among the Creatures bringing back a true report of their Order Causes Effects Philosophy therefore the Childe of the World and your own Mind is within your self perhaps not fashioned yet but like the World its Father as it was in the beginning a thing confused Do therefore as the Statuaries do who by hewing off that which is superfluous do not make but find the Image Or imitate the Creation If you will be a Philosopher in good earnest let your Reason move upon the Deep of your own Cogitations and Experience Those things that lie in Confusion must be set asunder distinguished and every one stampt with its own name set in order that is to say your Method must resemble that of the Creation The order of the Creation was Light Distinction of Day and Night the Firmament the Luminaries Sensible Creatures Man and after the Creation the Commandement Therefore the order of Contemplation will be Reason Definition Space the Starres Sensible Quality Man and after Man is grown up Subjection to Command In the first part of this Section which is entitled Logique I set up the light of Reason In the Second which hath for title the Grounds of Philosophy I distinguish the most common Notions by accurate definition for the avoiding of confusion and obscurity The third part concerns the Expansion of Space that is Geometry The fourth contains the Motion of the Starres together with the doctrine of Sensible Qualities In the second Section if it please God shall be handled Man In the third Section the doctrine of Subjection is handled already This is the Method I followed and if it like you you may use the same for I do but propound not commend to you any thing of mine But whatsoever shall be the Method you will like I would very fain commend Philosophy to you that is to say the study of Wisdome for want of which we have all suffered much dammage lately For even they that study Wealth do it out of love to Wisdome for their Treasures serve them but for a Looking-glass wherin to behold and contemplate their owne Wisdome Nor do they that love to be employed in publike business aime at any thing but place wherein to shew their Wisdome Neither do Voluptuous men neglect Philosophy but onely because they know not how great a pleasure it is to the Mind of Man to be ravished in the vigorous and perpetual embraces of the most beauteous World Lastly though for nothing else yet because the Mind of Man is no less impatient of Empty Time then Nature is of Empty Place to the end you be not forced for want of what to do to be troublesome to men that have business or take hurt by falling into idle Company but have somewhat of your own wherewith to fill up your time I recommend unto you the Study of Philosophy Farewell T. H. The Titles of the CHAPTERS The first Part or Logique CHAP. 1 Of Philosophy CHAP. 2 Of Names CHAP. 3 Of Proportion CHAP. 4 Of Syllogisme CHAP. 5 Of Erring Falsity and Captions CHAP. 6 Of Method The Second Part or The first Grounds of Philosophy CHAP. 7 Of Place and Time CHAP. 8 Of Body and Accident CHAP. 9 Of Cause and Effect CHAP. 10 Of Power and Act. CHAP. 11 Of Identity and Difference CHAP. 12 Of Quantity CHAP. 13 Of Analogisme or the Same Proportion CHAP. 14 Of Straight and Crocked Angle and Figure The third Part Of the Proportions of Motions and Magnitudes CHAP. 15 Of the Nature Properties and divers considerations of Motion and Endeavour CHAP. 16 Of Motion Accelerated and Uniform and of Motion by Concourse CHAP. 17 Of Figures Deficient CHAP. 18 Of the Equation of Straight Lines which the Crooked Lines of Parabolas and other Figures made in imitation of Parabolas CHAP. 19 Of Angles of Incidence and Reflexion equal by supposition CHAP. 20 Of the Dimension of a Circle and the Division of Arches or Angles CHAP. 21 Of Circular Motion CHAP. 22 Of other Variety of Motions CHAP. 23 Of the Center of Equiponderation of Bodies pressing downwards in straight parallel lines CHAP. 24 Of Refraction and Reflexion The fourth Part of Physiques or the Phaenomena of Nature CHAP. 25 Of Sense and Animall Motion CHAP. 26 Of the World and of the Starres CHAP. 27 Of Light Heat and of Colours CHAP. 28 Of Cold Wind Hard Ice Restitution of Bodies bent Diaphanous Lightning and Thunder and of the Heads of Rivers CHAP. 29 Of Sound Odour Savour and Touch. CHAP. 30 Of Gravity COMPUTATION OR LOGIQUE CHAP. I. Of Philosophy 1 The Introduction 2 The Definition of Philosophy explained 3 Ratiocination of the Mind 4 Properties what they are 5 How Properties are known by Generation contrarily 6 The Scope of Philosophy 7 The Utility of it 8 The Subject 9 The Parts of it 10 The Epilogue PHILOSOPHY seems to me to be amongst men now in the same manner as Corn and Wine are said to have been in the world in ancient time For from the beginning there were Vines and Ears of Corn growing here and there in the fields but no care was taken for the
neer enough to any Body we perceive the Motion and Going of the same we distinguish it thereby from a Tree a Column and other fixed Bodies and so that motion or going is the Property thereof as being proper to living creatures and a faculty by which they make us distinguish them from other Bodies 5 How the knowledge of any Effect may be gotten from the knowledge of the Generation thereof may easily be understood by the example of a Circle For if there be set before us a plain figure having as neer as may be the figure of a Circle we cannot possibly perceive by sense whether it be a true Circle or no then which neverthelesse nothing is more easie to be known to him that knowes first the Generation of the propounded figure For let it be known that the figure was made by the circumduction of a Body whereof one end remained unmoved and we may reason thus a Body carried about retaining alwayes the same length applies it selfe first to one Radius then to another to a third a fourth and successively to all and therefore the same length from the same point toucheth the circumference in every part thereof which is as much to say as all the Radii are equal We know therefore that from such generation proceeds a figure from whose one middle point all the extreame points are reached unto by equal Radii And in like manner by knowing first what figure is set before us we may come by Ratiocination to some Generation of the same though perhaps not that by which it was made yet that by w ch it might have been made for he that knows that a Circle has the property above declared will easily know whether a Body carried about as is said will generate a Circle or no. 6 The End or Scope of Philosophy is that we may make use to our benefit of effects formerly seen or that by applicatiō of Bodies to one another we may produce the like effects of those we conceive in our minde as far forth as matter strength industry will permit for the commodity of humane life For he inward glory and triumph of mind that a man may have for the mastering of some difficult and doutfull matter or for the discovery of some hidden truth is not worth so much paines as the study of Philosophy requires nor need any man care much to teach another what he knowes himselfe if he think that will be the onely benefit of his labour The end of Knowledge is Power and the use of Theoremes which among Geometricians serve for the finding out of Properties is for the construction of Problemes and lastly the scope of all speculation is the performing of some action or thing to be done 7 But what the Utility of Philosophy is especially of Natural Philosophy and Geometry will be best understood by reckoning up the chief commodities of which mankind is capable and by comparing the manner of life of such as enjoy them with that of others which want the same Now the greatest commodities of mankind are the Arts namely of measuring Matter and Motion of moving ponderous Bodies of Architecture of Navigation of making instruments for all uses of calculating the Coelestiall Motions the Aspects of the Stars and the parts of Time of Geography c. By which Sciences how great benefits men receive is more easily understood then expressed These benefits are enjoyed by almost all the people of Europe by most of those of Asia and by some of Africa but the Americans and they that live neer the Poles do totally want them But why Have they sharper wits then these Have not all men one kinde of soule and the same faculties of mind What then makes this difference except Philosophy Philosophy therefore is the cause of all these benefits But the Utility of Morall and Civil Philosophy is to be estimated not so much by the commodities we have by knowing these Sciences as by the calamities we receive from not knowing them Now all such calamities as may be avoided by humane industry arise from warre but chiefly from Civil warre for from this proceed Slaughter Solitude and the want of all things But the cause of warre is not that men are willing to have it for the Will has nothing for Object but Good at least that which seemeth good Nor is it from this that men know not that the effects of war are evil for who is there that thinks not poverty and losse of life to be great evils The cause therefore of Civill warre is that men know not the causes neither of Warre nor Peace there being but few in the world that have learned those duties which unite and keep men in peace that is to say that have learned the rules of civill life sufficiently Now the knowledge of these rules is Morall Philosophy But why have they not learned them unlesse for this reason that none hitherto have taught them in a clear and exact method For what shall we say Could the ancient Masters of Greece Egypt Rome and others perswade the unskillfull multitude to their innumerable opinions concerning the nature of their Gods which they themselves knew not whether they were true or false and which were indeed manifestly false absurd could they not perswade the same multitude to civill duty if they themselves had understood it Or shall those few writings of Geometricians which are extant be thought sufficient for the taking away of all controversy in the matters they treat of and shall those innumerable and huge Volumes of Ethicks be thought unsufficient if what they teach had been certain and well demonstrated What then can be imagined to be the cause that the writings of those men have increased science and the writings of these have increased nothing but words saving that the former were written by men that knew and the later by such as knew not the doctrine they taught onely for ostentation of their wit and eloquence Neverthelesse I deny not but the reading of some such books is very delightfull for they are most eloquently written and containe many cleer wholsome and choice sentences which yet are not universally true though by them universally pronounced From whence it comes to passe that the circumstances of times places and persons being changed they are no lesse frequently made use of to confirme wicked men in their purposes then to make them understand the precepts of Civill duties Now that which is chiefly wanting in them is a true and certaine rule of our actions by which we might know whether that we undertake be just or unjust For it is to no purpose to be bidden in every thing to do Right before there be a certain Rule and measure of Right established which no man hitherto hath established Seeing therefore from the not knowing of Civill duties that is from the want of Morall science proceed Civill warres and the greatest calamities of mankind we may very well attribute to
be demonstrated by good reason to be so CHAP. III. Of Proposition 1 Divers Kinds of Speech 2 Proposition defined 3 Subject Praedicate and Copula what they are and Abstract and Concrete what The Use and Abuse of Names Abstract 5 Proposition Universal and Particular 6 Affirmative and Negative 7 True and False 8 True and False belongs to Speech and not to Things 9 Proposition Primary not Primary Definion Axiome Petition 10 Proposition Necessary and Contingent 11 Categoricall and Hypotheticall 12 The same Proposition diversly pronounced 13 Propositions that may be reduced to the same Categoricall Proposition are Equipollent 14 Universal Propositions converted by Contradictory Names are Equipollent 15 Negative Propositions are the same whether the Negation be before or after the Copula 16 Particular Propositions simply converted are Equipollent 17 What are Subaltern Contrary Subcontrary and Contradictory Propositions 18 Consequence what it is 19 Falsity cannot follow from Truth 20 How one Proposition is the Cause of another 1_FRom the Connection or Contexture of Names arise diverse kinds of Speech whereof some signifie the Desires and Affections of Men such are first Interrogations which denote the desire of Knowing as Who is a good Man In which speech there is one Name expressed another desired and expected from him of whom we aske the same Then Prayers which signifie the desire of having something Promises Threats Wishes Commands Complaints and other significations of other Affections Speech may also be Absurd and Insignificant as when there is a succession of Words to which there can be no succession of Thoughts in the mind to answer them and this happens often to such as understanding nothing in some subtil matter doe neverthelesse to make others beleeve they understand speake of the same incoherently For the connection of incoherent Words though it want the end of Speech which is Signification yet it is Speech and is used by the Writers of Metaphysicks almost as frequently as Speech significative In Philosophy there is but one kinde of Speech usefull which some call in Latine Dictum others Enuntiatum Pronunciatum but most men call it Proposition and is the speech of those that Affirm or Deny and expresseth Truth or Falsity 2 A PROPOSITION is a Speech consisting of two Names copulated by which he that speaketh signifies he conceives the later Name to be the Name of the same thing whereof the former is the Name or which is all one that the former Name is comprehended by the later For example this speech Man is a Living Creature in which two Names are copulated by the verb Is is a Proposition for this reason that he that speakes it conceives both Living Creature and Man to be Names of the same thing or that the former Name Man is comprehended by the later Name Living Creature Now the former Name is commonly called the Subject or Antecedent or the Contained Name and the later the Praedicat Consequent or Containing Name The signe of Connection amongst most Nations is either some word as the word is in the Proposition Man is a living Creature or some Case or Termination of a word as in this Proposition Man walketh which is equivalent to this Man is walking the Termination by which it is said he walketh rather then he is walking signifieth that those two are understood to be copulated or to be Names of the same Thing But there are or certainly may be some Nations that have no word which answers to our Verbe Is who neverthelesse forme Propositions by the position onely of one Name after another as if instead of Man is a Living Creature it should be said Man a Living Creature for the very order of the Names may sufficiently shew their connection and they are as apt and usefull in Philosophy as if they were copulated by the Verbe Is. 3 Wherefore in every Proposition three things are to be considered viz. the two Names which are the Subject and the Praedicate and their Copulation both which Names raise in our Minde the Thought of one and the same Thing but the Copulation makes us thinke of the Cause for which those Names were imposed on that Thing As for example when we say a Body is moveable though we conceive the same thing to be designed by both those Names yet our Minde rests not there but searches further what it is to be a Body or to be Moveable that is wherein consists the difference betwixt these and other Things for which these are so called others are not so called They therefore that seeke what it is to be any thing as to be Moveable to be Hot c. seek in Things the causes of their Names And from hence arises that distinction of Names touched in the last Chap. into Concrete and Abstract For Concrete is the Name of any thing which we suppose to have a being and is therefore called the Subject in Latine Suppositum and in Greek 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 as Body Moveable Moved Figurate a Cubit high Hot Cold Like Equal Appius Lentulus and the like and Abstract is that which in any Subject denotes the Cause of the Concrete Name as to be a Body to be Moveable to be Moved to be Figurate to be of such Quantity to be Hot to be Cold to be Like to be Equall to be Appius to be Lentulus c. Or Names equivalent to these which are most commonly called Abstract Names as Corporeity Mobility Motion Figure Quantity Heat Cold Likenesse Equality and as Cicero has it Appiety and Lentulity Of the same kind also are Infinitives for to Live and to Move are the same with Life and Motion or to be Living and to be Moved But Abstract Names denote onely the Causes of Concrete Names and not the Things themselves For example when we see any thing or conceive in our Minde any Visible thing that Thing appears to us or is conceived by us not in one Point but as having Parts distant from one another that is as being extended and filling some space Seeing therefore we call the Thing so conceived Body the cause of that name is that that Thing is extended or the Extension or Corporeity of it So when we see a Thing appeare sometimes here sometimes there and call it Moved or Removed the Cause of that Name is that it is Moved or the Motion of the same And these Causes of Names are the same with the Causes of our Conceptions namely some Power or Action or Affection of the Thing conceived which some call the Manner by which any thing workes upon our senses but by most men they are called Accidents I say Accidents not in that sense in which Accident is opposed to Necessary but so as being neither the Things themselves nor parts thereof do neverthelesse accompany the Things in such manner that saving Extension they may all perish and 〈◊〉 destroyed but can never be abstracted 4 There is also this difference betwixt Concrete and Abstract Names that those
the same Quality as Every Man is a Living Creature Some Man is a Living Creature or No Man is Wise Some Man is not Wise. Of these iâ— the Universal be true the Particular will be true also Contrary are Universal Propositions of different Quality as Every Man is happy No Man is happy And of these if one be true the other is false also they may both be false as in the example given Subcontrary are Particular Propositions of different Quality as Some Man is learned Some Man is not learned which cannot be both false but they may be both true Contradictory are those that differ both in Quantity and Quality as Every Man is a Living Creature Some Man is not a Living Creature which can neither be both true nor both false 18 A Proposition is said to follow from two other Propositions when these being granted to be true it cannot be denyed but the other is true also For example let these two Propositions Every Man is a Living Creature and Every Living Creature is a Body be supposed true that is that Body is the Name of Every Living Creature and Living Creature the Name of Every Man Seeing therefore if these be understood to be true it cannot be understood that Body is not the name of Every man that is that Every Man is a Body is false this Proposition will be said to follow from those two or to be necessarily inferred from them 19 That a true Proposition may follow from false Propositions may happen sometimes but false from true never For if these Every Man is a Stone and Every Stone is a Living Creature which are both false be granted to be true it is granted also that Living Creature is the name of Every Stone and Stone of Every Man that is that Living Creature is the Name of Every Man that is to say this Proposition Every Man is a Living Creature is true as it is indeed true Wherefore a true Proposition may sometimes follow from false But if any two Propositions be true a false one can never follow from them For if true follow from false for this reason onely that the false are granted to be true then truth from two truths granted will follow in the same manner 20 Now seeing none but a true Proposition will follow from true and that the understanding of two Propositions to be true is the cause of understanding that also to be true which is deduced from them the two Antecedent Propositions are commonly called the Causes of the inferred Proposition or Conclusion And from hence it is that Logicians say the Premisses are Causes of the Conclusion which may passe though it be not properly spoken for though Understanding be the cause of Understanding yet Speech is not the cause of Speech But when they say the Cause of the Properties of any thing is the Thing it self they speake absurdly Eor example if a Figure be propounded which is Triangular Seeing every Triangle has all its angles together equal to two right angles from whence it follows that all the angles of that Figure are equal to two right angles they say for this reason that that Figure is the Cause of that Equality But seeing the Figure does not it self make its angles and therefore cannot be said to be the Efficient-Cause they call it the formall-Formall-Cause whereas in deed it is no Cause at all nor does the Property of any Figure follow the Figure but has its Being at the same time with it only the Knowledge of the Figure goes before the Knowledge of the Properties and one Knowledge is truly the Cause of another Knowledge namely the Efficient-Cause And thus much concerning Proposition which in the Progress of Philosophy is the first Step like the moving towards of one Foot By the due addition of another Step I shall proceed to Syllogisme and make a compleat Pace Of which in the next Chapter CHAP. IV. Of Syllogisme 1 The Definition of Syllogisme 2 In a Syllogisme there are but three Termes 3 Major Minor and Middle Term also Major and Minor Proposition what they are 4 The Middle Terme in every Syllogisme ought to be determined in both the Propositions to one and the same thing 5 From two Particular Propositions nothing can be concluded 6 A Syllogisme is the Collection of two Propositions into one Summe 7 The Figure of a Syllogisme what it is 8 What is in the mind answering to a Syllogisme 9 The first Indirect Figure how it is made 10 The second Indirect Figure how made 11 How the third Indirect Figure is made 12 There are many Moods in every Figure but most of them Uselesse in Philosophy 13 An Hypotheticall Syllogisme when equipollent to a Categoricall 1. A Speech consisting of three Propositions from two of which the third followes is called a SYLLOGISME and that which followes is called the Conclusion the other two Premisses For example this Speech Every man is a Living Creature Every Living Creature is a Body therefore Every Man is a Body is a Syllogisme because the third Proposition follows from the two first that is if those be granted to be true this must also be granted to be true 2 From two Propositions which have not one Terme common no Conclusion can follow and therefore no Syllogisme can be made of them For let any two Premisses A man is a Living Creature A Tree is a Plant be both of them true yet because it cannot be collected from them that Plant is the Name of a Man or Man the Name of a Plant it is not necessary that this Conclusion A Man is a Plant should be true Corollary Therefore in the Premisses of a Syllogisme there can be but three Termes Besides there can be no Terme in the Conclusion which was not in the Premisses For let any two Premisses be A Man is a Living Creature A Living Creature is a Body yet if any other Terme be put in the Conclusion as Man is two footed though it be true it cannot follow from the Premisses because from them it cannot be collected that the Name Two footed belongs to a Man and therefore againe In every Syllogisme there can be but three Termes 3 Of these Termes that which is the Predicate in the Conclusion is commonly called the Major that which is the Subject in the Conclusion the Minor and the other is the Middle Term as in this Syllogisme A Man is a Living Creature A Living Creature is a Body therefore A Man is a Body Body is the Major Man the Minor and Living Creature the Middle Term. Also of the Premisses that in which the Major Terme is found is called the Major Proposition and that which has the Minor Term the Minor Proposition 4 If the Middle Terme be not in both the Premisses determined to one and the same singular thing no Conclusion will follow nor Syllogisme be made For let the Minor Terme be Man the Middle Terme Living Creature and the Major Term
thither which is proper to Bodies also A Shadow is Moved or is a Body Light is Moved or is a Body Colour is the Obâ—ect of Sight Sound of Hearing Space or Place is Extended and innumerable others of this kind For seeing Ghosts sensible Species a Shadow Light Colour Sound Space c. appeare to us no lesse sleeping then waking they cannot be things without us but onely Phantasmes of the mind that imagins them and therefore the Names of these copulated with the Names of Bodies cannot constitute a true Proposition 5 False Propositions of the third kind are such as these Genus est Ens Universale est Ens Ens de Ente Praedicatur For Genus and Universale and Praedicare are Names of Names and not of Things Also Number is Infinite is a false Proposition for no number can be Infinite but onely the word Number is then called an Indefinite Name when there is no determined Number answering to it in the Mind 6 To the fourth kind belong such false Propositions as these An Object is of such Magnitude or Figure as appeares to the Beholders Colour Light Sound are in the Object and the like For the same Object appeares sometimes greater sometimes lesser sometimes square sometimes round according to the diversity of the Distance and Medium but the true Magnitude and Figure of the thing seen is allwayes one and the same so that the magnitude and figure which appeares is not the true magnitude and figure of the Object nor any thing but Phantasme and therefore in such Propositions as these the Names of Accidents are copulated with the Names of Phantasmes 7 Propositions are false in the fifth manner when it is said that The Definition is the Essence of a thing Whitenesse or some other Accident is the Genus or Universal For Definition is not the Essence of any thing but a speech signifying what we conceive of the Essence thereof and so also not Whitenesse it selfe but the word Whitenesse is a Genus or an Universall Name 8 In the sixth manner they Erre that say the Idea of any thing is Universal as if there could be in the Mind an Image of a Man which were not the Image of some one Man but of Man simply which is impossible for every Idea is one and of onething but they are deceived in this that they put the Name of the thing for the Idea thereof 9 They erre in the seventh manner that make this distinction between things that have being that some of them exist by themselves others by Accident Namely because Socrates is a Man is a Necessary Proposition and Socrates is a Musician a Contingent Proposition therefore they say some things exist necessarily or by themselves others contingently or by Accident whereby seeing Necessary Contingent By it selfe By Accident are not Names of Things but of Propositions they that say any thing that has being exists by Accident copulate the Name of a Proposition with the Name of a Thing In the same manner also they Erre which place some Ideas in the Understanding others in the Fancy as if from the Understanding of this Proposition Man is a Living Creature we had one Idea or Image of a Man derived from sense to the Memory and another to the Understanding wherein that which deceives them is this that they think one Idea should be answerable to a Name another to a Proposition which is false for Prâ—position signifies onely the order of those things one after another which we observe in the same Idea of Man so that this Proposition Man is a Living Creature raises but one Idea in us though in that Idea we consider that first for which he is called Man and next that for which he is called Living Creature The Falsities of Propositions in all these several manners is to be discovered by the Definitions of the Copulated Names 10 But when Names of Bodies are copulated with Names of Bodies Names of Accidents with Names of Accidents Names of Names with Names of Names and Names of Phantasmes with Names of Phantasmes if we neverthelesse remaine still doubtfull whether such Propositions are true we ought then in the first place to find out the Definition of both those Names and againe the Definitions of such Names as are in the former Definition and so proceed by a continuall Resolution till we come to a simple Name that is to the most Generall or most Universall Name of that kind and if after all this the Truth or Falsity thereof be not evident we must search it out by Philosophy and Ratiocination beginning from Definitions For every Proposition Universally true is either a Definition or part of a Definition or the evidence of it depends upon Definitions 11 That fault of a Syllogisme which lyes bid in the Forme thereof will allwayes be found either in the implication of the Copula with one of the Termes or in the Aequivocation of some word and in either of these wayes there will be four Terms which as I have shewne cannot stand in a true Syllogisme Now the implication of the Copula with either Terme is easily detected by reducing the Propositions to plain and cleere Praedication as for example if any man should argue thus The Hand toucheth the Pen The Pen toucheth the Paper Therefore The Hand toucheth the Paper the Fallacy will easily appear by reducing it thus The Hand is touching the Pen The Pen is touching the Paper Therefore The Hand is touching the Paper where there are manifestly these four Termes The Hand Touching the Pen The Pen and Touching the Paper But the danger of being deceived by Sophismes of this kind does not seem to be so great as that I need insist longer upon them 12 And though there may be Fallacy in Aequivocal Terms yet in those that be manifestly such there is none at all nor in Metaphors for they professe the transferring of Names from one thing to another Neverthelesse sometimes Aequivocalls and those not very obscure may deceive as in this argumentation It belongs to Metaphysicks to treat of Principles But the first Principles of all is that the same thing cannot both exist and not exist at the same time and therefore it belongs to Metaphysicks to treat whether the same thing may both exist and not exist at the same time where the Fallacy lies in the Aequivocation of the word Principle for whereas Aristotle in the beginning of his Metaphysicks sayes that the treating of Principles belongs to primary science he understands by Principles Causes of things and certaine Existences which he calls Primary but where he sayes a Primary Proposition is a Principle by Principle there he means the beginning and cause of Knowledge that is the understanding of words which if any man want he is incapable of learning 13 But the Captions of Sophists and Scepticks by which they were wont of old to deride and oppose Truth were faulty for the most part not in the Forme but in the Matter of
Syllogisme and they deceived not others oftner then they were themselves deceived For the force of that famous argument of Zeno against Motion consisted in this Proposition Whatsoever may be divided into parts infinite in number the same is infinite which he without doubt thought to be true yet neverthelesse is false For to be divided into infinite parts is nothing else but to be divided â—â—â—o as many parts as any man will But it is not necessary that a Line should have parts infinite in number or be infinite because I can divide and subdivide it as often as I please for how many parts soever I make yet their number is finite but because he that sayes Parts simply without adding how many does not limit any number but leaves it to the determination of the Hearer therefore we say commonly a line may be divided infinitely which cannot be true in any other sense And thus much may suffice concerning Syllogisme which is as it were the first Pace towards Philosophy in which I have said as much as is necessary to teach any man from whence all true argumentation has its force And to enlarge this Treatise with all that may be heaped together would be as superfluous as if one should as I said before give a young child Precepts for the teaching of him to goe for the Art of Reasoning is not so well learned by Precepts as by Practice and by the reading of those books in which the Conclusions are all made by severe Demonstration And so I pass on to the way of Philosophy that is to the Method of Study CHAP. VI. Of Method 1 Method and Science defined 2 It is more easily known concerning Singular then Universall things That they are and contrarily it iâ— more easily knowne concerning Universall then Singular things Why they are or what are their Causes 3 What it is Philosophers seek to know 4 The first Part by which Principles are found out is purely Analyticall 5 The highest Causes and most Universall in every kind are knowne by themselves 6 Method from Principles fonnd out tending to Science simply what it is 7 That Method of Civill and Naturall Science which proceeds from Sense to Principles is Analytical and againe that which begins at Principles is Syntheticall 8 The Method of searching out whether any thing propounded be Matter or Accident 9 The Method of seeking whether any Accident be in this or in that Subject 10 The Method of searching after the Cause of any Effect propounded 11 Words serve to Invention as Markes to Demonstration as Signes 12 The Method of Demonstration is Syntheticall 13 Definitions onely are Primary and Universal Propositions 14 The Nature and Definition of a Definition 15 The Properties of a Definition 16 The Nature of a Demonstration 17 The Properties of a Demonstration and Order of things to be demonstrated 18 The Faults of a Demonstration 19 Why the Analyticall Method of Geâ—metricians cannot be treated of in this place 1 FOr the understanding of Method it will be necessary for me to repeat the definition of Philosophy delivered above Chap. 1. Art 2. in this manner Philosophy is the knowledge we acquire by true Ratiocination of Appearances or apparent Effects from the knowledge we have of some possible Production or Generation of the same and of such Production as has been or may be from the knowledge we have of the Effects METHOD therefore in the Study of Philosophy is the shortest way of finding out Effects by their known Causes or of Causes by their known Effects But we are then said to know any Effect when we know that there be Causes of the same and in what Subiect those Causes are and in what Subiect they produce that Effect and in what Manner they work the same And this is the Science of Causes or as they call it of the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 All other Science which is called the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 is either Perception by Sense or the Imagination or Memory remaining after such Perception The first Beginnings therefore of Knowledge are the Phantasmes of Sense and Imagination and that there be such Phantasmes we know well enough by Nature but to know why they be or from what Causes they proceed is the work of Ratiocination which consists as is said above in the 1. Chap. 2. Art in Composition and Division or Resolution There is therefore no Method by which we find out the Causes of things but is either Compositive or Resolutive or partly Compositive and partly Resolutive And the Resolutive is commonly called Analyticall Method as the Compositive is called Syntheticall 2 It is common to all sorts of Method to proceed from known things to unknown and this is manifest from the cited Definition of Philosophy But in Knowledge by Sense the whole object is more known then any part thereof as when we see a Man the Conception or whole Idea of that Man is first or more known then the particular Ideas of his being figurate animate and rationall that is we first see the whole Man and take notice of his Being before we observe in him those other Particulars And therefore in any knowledge of the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 or that any thing is the beginning of our search is from the whole Idea and contrarily in our knowledge of the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 or of the Causes of any thing that is in the Sciences we have more knowledge of the Causes of the Parts then of the Whole For the Cause of the Whole is compounded of the Causes of the Parts but it is necessary that we know the things that are to be compounded before we can know the whole Compound Now by Parts I do not here mean Parts of the thing it self but Parts of its Nature as by the Parts of Man I do not understand his Head his Shoulders his Arms c. but his Figure Quantity Motion Sense Reason and the like which Accidents being compounded or put together constitute the whole Nature of Man but not the man himselfe And this is the meaning of that common saying namely that some things are more knowne to us others more known to Nature for I do not thinke that they which so distinguish mean that something is known to Nature which is known to no man and therefore by those things that are more known to Us we are to understand things we take notice of by our Senses and by more known to Nature those we acquire the knowledge of by Reason for in this sense it is that the Whole that is those things that have Universal Names which for brevities sake I call Universall are more knowne to us then the Parts that is such things as have Names lesse Universal which I therefore call Singular and the Causes of the Parts are more known to Nature then the Cause of the Whole that is Universalls then Singulars 3 In the Study of Philosophy men search after Science either Simply or
the fourth place which two considerations comprehend that part of Philosophy which is called Physiques And in these four parts is contained whatsoever in Naturall Philosophy may be explicated by Demonstration properly so called For if a Cause were to be rendred of Natural Appearances in special as what are the Motions and Influences of the heavenly Bodies and of their parts the reason hereof must either be drawn from the parts of the Sciences above mentioned or no reason at all will be given but all left to uncertaine conjecture After Physiques we must come to Morall Philosophy in which we are to consider the Motions of the Mind namely Appetite Aversion Love Benevolence Hope Fear Anger Emulation Envy c. what Causes they have and of what they be Causes And the reason why these are to be considered after Physiques is that they have their Causes in Sense and Imagination which are the Subject of Physicall Contemplation Also the reason why all these Things are to be searched after in the order abovesaid is that Physiques cannot be understood except we know first what Motions are in the smallest parts of Bodies nor such Motion of Parts till we know what it is that makes another Body move nor this till we know what Simple Motion will effect And because all Appearance of things to sense is determined and made to be of such and such Quality and Quantity by Compounded Motions every one of which has a certaine degree of Velocity and a certaine and determined way therefore in the first place we are to search out the wayes of Motion simply in which Geometry consists next the wayes of such generated Motions as are manifest and lastly the wayes of internal and invisible Motions which is the Enquiry of Naturall Philosophers And therefore they that study Naturall Philosophy study in vaine except they begin at Geometry and such Writers or Disputers thereof as are ignorant of Geometry do but make their Readers and Hearers lose their time 7 Civill and Morall Philosophy doe not so adhere to one another but that they may be severed For the Causes of the Motions of the Mind are known not onely by Ratiocination but also by the Experience of every man that takes the paines to observe those Motions within himselfe And therefore not only they that have attained the knowledge of the Passions and Perturbations of the Mind by the Syntheticall Method and from the very first Principles of Philosophy may by proceeding in the same way come to the Causes and Necessity of constituting Common-wealths and to get the Knowledge of what is Naturall Right and what are Civill Duties and in every kind of Government what are the Rights of the Commonwealth and all other Knowledge appertaining to Civill Philosophy for this reason that the Principles of the Politiques consist in the Knowledge of the Motions of the Mind and the Knowledge of these Motions from the knowledge of Sense and Imagination but even they also that have not learned the first part of Philosophy namely Geometry and Physiques may notwithstanding attain the Principles of Civill Philosophy by the Analyticall Method For if a Question be propounded as Whether such an Action be Just or Uniust if that Uniust be resolved into Fact against Law and that notion of Law into the Command of him or them that have Coercive Power and that Power be derived from the Wills of Men that constitute such Power to the end they may live in Peace they may at last come to this that the Appetites of Men and the Passions of their Minds are such that unlesse they be restrained by some Power they will alwayes be making warre upon one another which may be known to be so by any mans experience that will but examine his owne Mind And therefore from hence he may proceed by Compounding to the determination of the Justice or Injustice of any propounded Action So that it is manifest by what has been said that the Method of Philosophy to such as seek Science simply without propounding to themselves the Solution of any Particular question is partly Analyticall and partly Syntheticall namely that which proceeds from Sense to the invention of Principles Analyticall and the rest Syntheticall 8 To those that seek the Cause of some certaine and pro pounded Appearance or Effect it happens sometimes that they know not whether the thing whose Cause is sought after be Matter or Body or some Accident of a Body For though in Geometry when the Cause is sought of Magnitude or Proportion or Figure it be certainly known that these things namely Magnitude Proportion and Figure are Accidents yet in Naturall Philosophy where all questions are concerning the Causes of the Phantasmes of sensible things it is not so easie to discern between the things themselves from which those Phantasmes proceed and the Appearances of those things to the sense which have deceived many especially when the Phantasmes have been made by Light For Example a Man that looks upon the Sunne has a certaine shining Idea of â—â—e Magnitude of about a foâ—t over and this he calls the Sunne thougâ—…e know the Sunne to be truly a great deale bigger and in like 〈…〉 the Phantasme of the same thing appears sometimes â—â—und by being 〈…〉 a â—arre off and sometimes square by being neerer Whereupon â—t may well be doubted whether that Phantasme be Maâ—… or some Body Naturall or onely some Accident of a Body in the examination of which doubt we may use this Method The Properties of Matter and Accidents already found out by Us by the Syntheticall Method from their Definitions are to be compared with the Idea we have before us and if it agree with the Properties of Matter or Body then it is a Body otherwise it is an Accident Seeing therefore Matter cannot by any endeavour of ours be either Made or Destroyed or Encreased or Diminished or Moved out of its place whereas that Idea Appeares Vanishes is Encreased and Diminished and Moved hither and thither at pleasure we may certainly conclude that it is not a Body but an Accident onely And this Method is Syntheticall 9 But if there be a doubt made concerning the Subject of any known Accident for this may be doubted sometimes as in the praecedent example doubt may be made in what Subject that Splendor and apparent Magnitude of the Sunne is then our enquiry must proceed in this manner First Matter in Generall must be divided into parts as into Object Medium and the Sentient it selfe or such other parts as seem most conformable to the thing propounded Next these parts are severally to be examined how they agree with the Definition of the Subject and such of them as are not capable of that Accident are to be rejected For example If by any true Ratiocination the Sunne be found to be greater then its apparent Magnitude then that Magnitude is not in the Sunne If the Sunne be in one determined straight line and one determined
distance and the Magnitude and Splendor be seen in more lines and distances then one as it is in Reflection or Refraction then neither that Splendor nor apparent Magnitude are in the Sun it self and therefore the Body of the Sun cannot be the Subject of that Splendor and Magnitude And for the same reasons the Aire and other parts will be rejected till at last nothing remain which can be the Subject of that Splendor and Magnitude but the Sentient it selfe And this Method in regard the Subject is divided into parts is Analitycall and in regard the Properties both of the Subject and Accident are compared with the Accident concerning whose Subject the enquiry is made it is Syntheticall 10 But when we seek after the Cause of any propounded Effect we must in the first place get into our Mind an exact Notion or Idea of that which we call Cause namely that A Cause is the Summe or Aggregate of all such Accidents both in the Agents and the Patient as concurre to the producing of the Effect propounded all which existing together it cannot be understood but that the Effect existeth with them or that it cannot possibly exist if any one of them be absent This being known in the next place we must examine singly every Accident that accompanies or praecedes the Effect as farre forth as it seemes to conduce in any manner to the production of the same and see whether the propounded Effect may be conceived to exist without the existence of any of those Accidents and by this meanes separate such Accidents as do not concurre from such as concurre to produce the said Effect which being done we are to put together the concurring Accidents and consider whether we can possibly conceive that when these are all present the Effect propounded will not follow and if it be evident that the Effect will follow then that Aggregate of Accidents is the entire Cause otherwise not but we must still search out and put together other Accidents For example if the Cause of Light be propounded to be sought out first we examine things without us and find that whensoever Light appeares there is some principall Object as it were the fountaine of Light without which we cannot have any perception of Light and therefore the concurrence of that Object is necessary to the generation of Light Next we consider the Medium and find that unlesse it be disposed in a certaine manner namely that it be transparent though the Object remain the same yet the Effect will not follow and therefore the concurrence of Transparency is also necessary to the generation of Light Thirdly we observe our own Body and find that by the indisposition of the Eyes the Brain the Nerves and the Heart that is by Obstructions Stupidity and Debility we are deprived of Light so that a fitting disposition of the Organs to receive impressions from without is likewise a necessary part of the Cause of Light Again of all the Accidents inhaerent in the Object there is none that can conduce to the effecting of Light but onely Action or a certain Motion which cannot be conceived to be wanting whensoever the Effect is present for that any thing may shine it is not requisite that it be of such or such â—agnitude or Figure or that the whole Body of it be moved out of the place it is in unlesse it may perhaps be said that in the Sun or other Body that which causeth Light is the light it hath in it selfe which yet is but a trifling exception seeing nothing is meant thereby but the Cause of Light as if any man should say that the Cause of Light is that in the Sunne which produceth it it remaines therefore that the Action by which Light is generated is Motion only in the parts of the Object Which being understood we may easily conceive what it is the Medium contributes namely the continuation of that Motion to the Eye and lastly what the Eye and the rest of the Organs of the Sentient contribute namely the continuation of the same Motion to the last Organ of Sense the Heart And in this manner the Cause of Light may be made up of Motion continued from the Original of the same Motion to the Original of Vitall Motion Light being nothing but the alteration of Vitall Motion made by the impression upon it of Motion continued from the Object But I give this onely for an example for I shall speak more at large of Light and the generation of it in its proper place In the mean time it is manifest that in the searching out of Causes there is need partly of the Analyticall and partly of the Syntheticall Method of the Analyticall to conceive how circumstances conduce severally to the production of Effects and of the Syntheticall for the adding together and compounding of what they can effect singly by themselves And thus much may serve for the Method of Invention It remaines that I speake of the Method of Teaching that is of Demonstration and of the Meanes by which we demonstrate 11 In the Method of Invention the use of words consists in this that they may serve for Marks by which whatsoever we have found out may be recalled to memory for without this all our Inventions perish nor will it be possible for us to go on from Principles beyond a Syllogisme or two by reason of the weaknesse of Memory For example if any man by considering a Triangle set before him should find that all its angles together taken are equall to two right angles and that by thinking of the same tacitely without any use of words either understood or expressed and it should happen afterwards that another Triangle unlike the former or the same in different scituation should be offered to his consideration he would not know readily whether the same property were in this last or no but would be forced as often as a different Triangle were brought before him and the difference of Triangles is infinite to begin his contemplation anew which he would have no need to do if he had the use of Names for every Universal Name denotes the conceptions we have of infinite Singular things Neverthelesse as I said above they serve as Markes for the helpe of our Memory whereby we register to our selves our own Inventions but not as Signes by which we declare the same to others so that a man may be a Philosopher alone by himselfe without any Master Adam had this capacity But to Teach that is to Demonstrate supposes two at the least and Syllogisticall Speech 12 And seeing Teaching is nothing but leading the Mind of him we teach to the knowledge of our Inventions in that Track by which we attained the same with our own Mind therefore the same Method that served for our Invention will serve also for Demonstration to others saving that we omit the first part of Method which proceeded from the Sense of Things to Universal Principles which
end that the Reader may know that those Axioms are not indemonstrable therefore not Principles of Demonstration and from hence learn to be wary how he admits any thing for a Principle which is not at least as evident as these are Greater is defined to be that whose Part is Equal to the Whole of another Now if we suppose any Whole to be A and a Part of it to be B seeing the Whole B is Equal to it self and the same B is a Part of A therefore a Part of A will be Equal to the Whole B. Wherefore by the Definition above A is Greater then B which was to be proved CHAP. IX Of Cause and Effect 1 Action and Passion what they are 2 Action and Passion Mediate and Immediate 3 Cause simply taken Cause without which no Effect follows or Cause Necessary by Supposition 4 Cause Efficient and Material 5 An Entire Cause is alwayes sufficient to produce its Effect At the same instant that the Cause is Entire the Effect is produced Every Effect has a Necessary Cause 6 The Generation of Effects is Continual What is the Beginning in Causation 7 No Cause of Motion but in a Body Contiguous and Moved 8 The same Agents and Patients if alike disposed produce like Effects though at different times 9 All Mutation is Motion 10 Contingent Accidents what they are 1 A Body is said to Work upon or Act that is to say Do some thing to another Body when it either generates or destroys some Accident in it and the Body in which an Accident is generated or destroyed is said to Suffer that is to have something Done to it by another Body As when one Body by putting forwards another Body generates Motion in it it is called the AGENT and the Body in which Motion is so generated is called the PATIENT so Fire that warms the Hand is the Agent and the Hand which is warmed is the Patient That Accident which is generated in the Patient is called the EFFECT 2 When an Agent and Patient are Contiguous to one another their Action and Reason are then said to be Immediate otherwise Mediate and when another Body lying betwixt the Agent and Patient is Contiguous to them both it is then it self both an Agent and a Patient an Agent in respect of the Body next after it upon which it Works and a Patient in respect of the Body next before it from which it suffers Also if many Bodies be so ordered that every two which are next to one another be contiguous then all those that are betwixt the first and the last are both Agents and Patients and the first is an Agent onely and the last a Patient onely 3 An Agent is understood to produce its determined or certain Effect in the Patient according to some certain Accident or Accidents with which both it and the Patient are affected that is to say the Agent hath its Effect precisely such not because it is a Body but because such a Body or so Moved For otherwise all Agents seeing they are all Bodies alike would produce like Effects in all Patients and therefore the Fire for example does not warm because it is a Body but because it is Hot nor does one Body put forward another Body because it is a Body but because it is moved into the place of that other Body The Cause therefore of all Effects consists in certain Accidents both in the Agents and in the Patient which when they are all present the Effect is produced but if any one of them be wanting it is not produced and that Accident either of the Agent or Patient without which the Effect cannot be produced is called Causa sine qua non or Cause Necessary by Supposition as also the Cause Requisite for the Production of the Effect But a CAUSE simply or An Entire Cause is the Aggregate of all the Accidents both of the Agents how many soever they be and of the Patient put together which when they are all supposed to be present it cannot be understood but that the Effect is produced at the same instant and if any one of them be wanting it cannot be understood but that the Effect is not produced 4 The Aggregate of Accidents in the Agent or Agents requisite for the production of the Effect the Effect being produced is called the Efficient Cause thereof and the Aggregate of Accidents in the Patient the Effect being produced is usually called the Material Cause I say the Effect being produced for where there is no Effect there can be no Cause for nothing can be called a Cause where there is nothing that can be called an Effect But the Efficient and Material Causes are both but Partial Causes or Parts of that Cause which in the next precedent article I called an Entire Cause And from hence it is manifest that the Effect we expect though the Agents be not defective on their part may nevertheless be frustrated by a defect in the Patient and when the Patient is sufficient by a defect in the Agents 5 An Entire Cause is alwayes sufficient for the production of its Effect if the Effect be at all possible For let any Effect whatsoever be propounded to be produced if the same be produced it is manifest that the Cause which produced it was a sufficient Cause but if it be not produced and yet be possible it is evident that something was wanting either in some Agent or in the Patient without which it could not be produced that is that some Accident was wanting which was requisite for its Production and therefore that Cause was not Entire which is contrary to what was supposed It follows also from hence that in whatsoever instant the Cause is Entire in the same instant the Effect is produced For if it be not produced something is still wanting which is requisite for the production of it and therefore the Cause was not Entire as was supposed And seeing a Necessary Cause is defined to be that which being supposed the Effect cannot but follow this also may be collected that whatsoever Effect is produced at any time the same is produced by a Necessary Cause For whatsoever is produced in as much as it is produced had an Entire Cause that is had all those things which being supposed it cannot be understood but that the Effect follows that is it had a Necessary Cause And in the same manner it may be shewn that whatsoever Effects are hereafter to be produced shall have a Necessary Cause so that all the Effects that have been or shall be produced have their Ne cessity in things antecedent 6 And from this that whensoever the Cause is Entire the Effect is produced in the same instant it is manifest that Causation and the Production of Effects consist in a certain continual Progress so that as there is a continual Mutation in the Agent or Agents by the working of other Agents upon them so also the Patient upon
which they work is continually altered and changed For example as the Heat of the Fire encreases more and more so also the Effects thereof namely the Heat of such Bodies as are next to it again of such other Bodies as are next to them encreases more more accordingly which is already no litle argument that all Mutation consists in Motion onely the truth whereof shall be further demonstrated in the ninth Article But in this Progress of Causation that is of Action and Passion if any man comprehend in his imagination a part thereof and divide the same into parts the first part or Beginning of it cannot be considered otherwise then as Action or Cause for if it should be considered as Effect or Passion then it would be necessary to consider something before it for its Cause or Action which cannot be for nothing can be before the Beginning And in like manner the last part is considered onely as Effect for it cannot be called Cause if nothing follow it but after the last nothing follows And from hence it is that in all Action the Beginning and Cause are taken for the same thing But every one of the intermediate parts are both Action and Passion and Cause and Effect according as they are compared with the antecedent or subsequent part 7 There can be no Cause of Motion except in a Body Contiguous and Moved For let there be any two Bodies which are not contiguous and betwixt which the intermediate Space is empty or if filled filled with another Body which is at Rest and let one of the propounded Bodies be supposed to be at Rest I say it shall always be at Rest. For if it shall be Moved the Cause of that Motion by the 8th Chapter 19th Article will be in some external Body and therefore if between it and that external Body there be nothing but empty Space then whatsoever the disposition be of that external Body or of the Patient it self yet if it be supposed to be now at Rest we may conceive it wil continue so til it be touched by some other Body but seeing Cause by the Definition is the Aggregate of all such Accidents which being supposed to be present it cannot be conceived but that the Effect will follow those Accidents which are either in external Bodies or in the Patient it self cannot be the Cause of future Motion and in like manner seeing we may conceive that whatsoever is at Rest will still be at Rest though it be touched by some other Body except that other Body be moved therefore in a contiguous Body which is at Rest there can be no Cause of Motion Wherefore there is no Cause of Motion in any Body except it be Contiguous and Moved The same reason may serve to prove that whatsoever is Moved will alwayes be Moved on in the same way and with the same Velocity except it be hindered by some other Contiguous and Moved Body and consequently that no Bodies either when they are at Rest or when there is an interposition of Vacuum can generate or â—â—tinguish or lesson Motion in other Bodies There is one that has written that things Moved are more resisted by things at Rest then by things contrarily Moved for this reason that he conceived Motion not to be so contrary to Motion as Rest. That which deceived him was that the words Rest and Motion are but contradictory Names whereas Motion indeed is not resisted by Rest but by contrary Motion 8 But if a Body work upon another Body at one time and afterwards the same Body work upon the same Body at another time so that both the Agent and Patient and all their parts be in all things as they were and there be no difference except onely in time that is that one Action be former the other later in time it is manifest of it self that the Effects will be Equal and Like as not differing in any thing besides time And as Effects themselves proceed from their Causes so the diversity of them depends upon the diversity of their Causes also 9 This being true it is necessary that Mutation can be nothing else but Motion of the Parts of that Body which is Changed For First we do not say any thing is Changed but that which appears to our Senses otherwise then it appeared formerly Secondly both those Appearances are Effects produced in the Sentient therefore if they be differeÌ„t it is necessary by the preceding article that either some part of the Agent which was formerly at Rest is now Moved and so the Mutation consists in this Motion or some part which was formerly Moved is now otherwise Moved and so also the Mutation consists in this new Motion or which being formerly Moved is now at Rest which as I have shewn above cannot come to pass without Motion and so again Mutation is Motion or lastly it happens in some of these manners to the Patient or some of its parts so that Mutation howsoever it be made will consist in the Motion of the parts either of the Body which is perceived or of the Sentient Body or of both Mutation therefore is Motion namely of the parts either of the Agent or of the Patient which was to be demonstrated And to this it is consequent that Rest cannot be the Cause of any thing nor can any Action proceed from it seeing neither Motion nor Mutation can be caused by it 10 Accidents in respect of other Accidents which precede them or are before them in time upon which they do not depend as upon their Causes are called Contingent Accidents I say in respect of those Accidents by which they are not generated for in respect of their Causes all things come to pass with equal necessity for otherwise they would have no Causes at all which of things generated is not intelligible CHAP. X. Of Power and Act. 1 Power and Cause are the same thing 2 An Act is produced at the same instant in which the Power is Plenary 3 Active and Passive Power are parts onely of Plenary Power 4 An Act when said to be Possible 5 An Act Necessary and Contingent what 6 Active Power consists in Motion 7 Cause Formal and Final what they are 1_COrrespondent to Cause and Effect are POWER and ACT Nay those and these are the same things though for divers considerations they have divers names Forwhensoever any Agent has all those Accidents which are necessarily requisite for the production of some Effect in the Patient then we say that Agent has Power to produce that Effect if it be applyed to a Patient But as I have shewn in the precedent Chapter those Accidents constitute the Efficient Cause and therefore the same Accidents which constitute the Efficient Cause constitute also the Power of the Agent Wherefore the Power of the Agent and the Efficient Cause are the same thing But they are considered with this difference that Cause is so called in respect of the Effect already
produced and Power in respect of the same Effect to be produced hereafter so that Cause respects the Past Power the Future time Also the Power of the Agent is that which is commonly called Active Power In like manner whensoever any Patient has all those Accidents which it is requisite it should have for the production of some Effect in it we say it is in the Power of that Patient to produce that Effect if it be applyed to a fitting Agent But those Accidents as is defined in the precedent Chapter constitute the Material Cause and therefore the Power of the Patient commonly called Passive Power and Material Cause are the same thing but with this different consideration that in Cause the Past time and in Power the Future is respected Wherefore the Power of the Agent and Patient together which may be called Entire or Plenary Power is the same thing with Entire Cause for they both consist in the Sum or Aggregate of all the Accidents as well in the Agent as in the Patient which are requisite for the production of the Effect Lastly as the Accident produced is in respect of the Cause called an Effect so in respect of the Power it is called an Act. 2 As therefore the Effect is produced in the same instant in which the Cause is Entire so also every Act that may be produced is produced in the same instant in which the Power is Plenary And as there can be no Effect but from a Sufficient and Necessary Cause so also no Act can be produced but by Sufficient Power or that Power by which it could not but be produced 3 And as it is manifest as I have shewn that the Efficient and Material Causes are severally and by themselves parts onely of an Entire Cause and cannot produce any Effect but by being joyned together so also Power Active and Passive are parts onely of Plenary and Entire Power nor except they be joyned can any Act proceed from them and therefore these Powers as I said in the first Article are but conditionall namely the Agent has Power if it be applyed to a Patient and the Patient has Power if it be applyed to an Agent otherwise neither of them have Power nor can the Accidents which are in them severally be properly called Powers nor any Action be said to be Possible for the Power of the Agent alone or of the Patient alone 4 For that is an Impossible Act for the production of which there is no Power Plenary For seeing Plenary Power is that in which all things concurre which are requisite for the production of an Act if the Power shall never be Plenary there will always be wanting some of those things without which the Act cannot be produced wherefore that Act shall never be produced that is that Act is IMPOSSIBLE And every Act which is not Impossible is POSSIBLE Every Act therefore which is Possible shall at some time be produced for if it shall never be produced then those things shall never concurre which are requisite for the production of it wherefore that Act is Impossible by the Definition which is contrary to what was supposed 5 A Necessary Act is that the production whereof it is Impossible to hinder and therefore every Act that shall be produced shall necessarily be produced for that it shall not be produced is Impossible because as is already demonstrated every Possible Act shall at some time be produced Nay this Proposition What shall be shall be is as necessary a Proposition as this A Man is a Man But here perhaps some man may ask whether those Future things which are commonly called Contingents are Necessary I say therefore that generally all Contingents have their Necessary Causes as is shewn in the preceding Chapter but are called Contingents in respect of other Events upon which they do not depend as the Rain which shall be to morrow shall be Necessarily that is from necessary Causes but we think and say it happens by chance because we doe not yet perceive the Causes thereof though they exist now for men commonly call that Casuall or Contingent whereof they do not perceive the necessary Cause and in the same manner they use to speake of things past when not knowing whether a thing be done or no they say it is possible it never was done Wherefore all Propositions concerning Future things contingent or not contingent as this It will rayne to morrow or this To morrow the Sun will rise are either necessarily true or necessarily false but we call them Contingent because we doe not yet know whether they be true or false whereas their Verity depends not upon our Knowledge but upon the foregoing of their Causes But there are some who though they confess this whole Proposition To morrow it will either rain or not rain to be true yet they will not acknowledge the parts of it as To morrow it will rain or To morrow it will not rain to be either of them true by it self because they say neither this nor that is true determinately But what is this determinately true but true upon our knowledge or evidently true and therefore they say no more but that it is not yet known whether it be true or no but they say it more obscurely and darken the Evidence of the truth with the same words with which they endevour to hide their own ignorance 6 In the 9th Article of the precedent Chapter I have shewn that the Efficient Cause of all Motion and Mutation consists in the Motion of the Agent or Agents And in the first Article of this Chapter that the Power of the Agent is the same thing with the Efficient Cause From whence it may be understood that all Active Power consists in Motion also and that Power is not a certain Accident which differs from all Acts but is indeed an Act namely Motion which is therefore called Power because another Act shall be produced by it afterwards For example if of three Bodies the first put forwards the second and this the third the Motion of the second in respect of the first which produceth it is the Act of the second Body but in respect of the third it is the Active Power of the same second Body 7 The Writers of Metaphysiques reckon up two other Causes besides the Efficient and Material namely the ESSENCE which some call the Formal Cause and the End or Final Cause both which are nevertheless Efficient Causes For when it is said the Essence of a thing is the Cause thereof as to be Rational is the Cause of Man it is not intelligible for it is all one as if it were said To be a Man is the Cause of Man which is not well said And yet the knowledge of the Essence of any thing is the Cause of the knowledge of the thing it selfe for if I first know that a thing is Rational I know from thence that the same is Man but this is no
drawn from the propositions which prove the same But the cause of his construction is in the things themselves and consists in motion or in the concourse of motions Wherefore those propositions in which Analysis ends are Definitions but such as signifie in what manner the construction or generation of the thing proceeds For otherwise when he goes back by Synthesis to the proofe of his Probleme he will come to no Demonstration at all there being no true Demonstration but such as is scientificall and no Demonstration is scientifical but that which proceeds from the knowledge of the causes from which the construction of the Probleme is drawne To collect therefore what has been said into few words ANALYSIS is Ratiocination from the supposed construction or generation of a thing to the efficient cause or coefficient causes of that which is constructed or generated And SYNTHESIS is Ratiocination from the first causes of the Construction continued through all the middle causes till we come to the thing it selfe which is constructed or generated But because there are many means by which the same thing may be generated or the same Probleme be constructed therefore neither do all Geometricians nor doth the same Geometrician alwayes use one and the same Method For if to a certain quantity given it be required to construct another quantity equal there may be some that will enquire whether this may not be done by means of some motion For there are quantities whose equality and inequality may be argued from Motion and Time as well as from Congruence and there is motion by which two quantities whether Lines or Superficies though one of them be crooked the other straight may be made congruous or coincident And this method Archimedes made use of in his Book de Spiralibus Also the equality or inequality of two quantities may be found out and demonstrated from the consideration of Waight as the same Archimedes did in his Quadrature of the Parabola Besides equality and equality are found out often by the division of the two quantityes into parts which are considered as undivisible as Cavallerius Bonaventura has done in our time and Archimedes often Lastly the same is performed by the consideration of the Powers of lines or the roots of those Powers and by the multiplication division addition and substraction as also by the extraction of the roots of those Powers or by finding where straight lines of the same proportion terminate For example when any number of straight lines how many soever are drawne from a straight line and passe all through the same point looke what proportion they have and if their parts continued from the point retaine every where the same proportion they shall all terminate in a straight line And the same happens if the point be taken between two Circles So that the places of all their points of termination make either straight lines or circumferences of Circles and are called Plain Places So also when straight parallel lines are applyed to one straight line if the parts of the straight line to which they are applyed be to one another in proportion duplicate to that of the contiguous applyed lines they will all terminate in a Conical Section which Section being the place of their termination is called a Solid Place because it serves for the finding out of the quantity of any Equation which consists of three dimensions There are therfore three ways of finding out the cause of Equality or Inequality between two given quantities namely First by the Computation of Motions for by equal Motion equal Time equal Spaces are described and Ponderation is motion Secondly By Indivisibles because all the parts together taken are equal to the whole And thirdly by the Powers for when they are equall their roots also are equall and contrarily the Powers are equall when their roots are equal But if the question be much complicated there cannot by any of these wayes be constituted a certaine Rule from the supposition of which of the unknown quantities the Analysis may best begin nor out of the variety of Equations that at first appeare which we were best to choose but the successe will depend upon dexterity upon formerly acquired Science and many times upon fortune For no man can ever be a good Analyst without being first a good Geometrician nor do the rules of Analysis make a Geometrician as Synthesis doth which begins at the very Elements and proceeds by a Logical Use of the same For the true teaching of Geometry is by Synthesis according to Euclides method and he that hath Euclide for his Master may be a Geometrician without Vieta though Vieta was a most admirable Geometrician but he that has Vieta for his master not so without Euclide And as for that part of Analysis which works by the Powers though it be esteemed by some Geometricians not the chiefest to be the best way of solving all Problemes yet it is a thing of no great extent it being all contained in the doctrine of rectangles and rectangled Solids So that although they come to an Equation which determines the quantity sought yet they cannot sometimes by art exhibit that quantity in a Plain but in some Conique Section that is as Geometricians say not Geometrically but mechanically Now such Problemes as these they call Solid and when they cannot exhibit the quantity sought for with the helpe of a conique Section they call it a Lineary Probleme And therefore in the quantities of angles and of the arches of Circles there is no use at all of the Analyticks which proceed by the Powers so that the Antients pronounced it impossible to exhibit in a plaine the Division of Angles except bisection and the bisection of the bisected parts otherwise then mechanically For Pappus before the 31 proposition of his fourth Book distinguishing and defining the several kinds of Problemes says that some are Plain others Solid and others Lineary Those therefore which may be solved by straight lines and the circumferences of Circles that is which may be described with the Rule and Compass without any other Instrument are fitly called Plain for the lines by which such Problemes are found out have their generation in a Plain But those which are solved by the using of some one or more Conique Sections in their construction are called Solid because their construction cannot be made without using the superficies of solid figures namely of Cones There remains the third kinde which is called Lineary because other lines besides those already mentioned are made use of in their construction c. And a little after he sayes Of this kinde are the Spiral lines the Quadratrices the Conchoeides and the Cissoeides And Geometricians think it no small fault when for the finding out of a Plain Probleme any man makes use of Coniques or new Lines Now he ranks the Trisection of an angle among Solid Problemes and the Quinquesection among Lineary But what are the ancient Geometricians
first moved and rested if ever they rested at all afterwards Neither doth there appear any cause why the matter of the World should for the admission of motion be intermingled with empty spaces rather then full I say full but withall fluid Nor lastly is there any reason why those hard Atomes may not also by the motion of intermingled fluid matter be congregated brought together into compounded Bodies of such bigness as we see Wherefore nothing can by this argument be concluded but that motion was either coeternal or of the same duration with that which is moved neither of which conclusions consisteth with the doctrine of Epicurus who allows neither to the World nor to Motion any Beginning at all The necessity therefore of Vacuum is not hitherto demonstrated And the cause as far as I understand from them that have discoursed with me of Vacuum is this that whilest they contemplate the nature of Fluid they conceive it to consist as it were of small grains of hard matter in such manner as meal is fluid made so by grinding of the Corn when nevertheless it is possible to conceive Fluid to be of its own nature as homogeneous as either an Atome or as Vacuum it self The second of their arguments is taken from waight and is contained in these Verses of Lucretius Corporis officium est quoniam premere omnia deorsum Contrà autem natura manet sine Pondere Inanis Ergo quod magnum est aeque Leviusque videtur Nimirum plus esse sibi declarat Inanis That is to say Seeing the office and property of Body is to press all things downwards and on the contrary seeing the nature of Vacuum is to have no waight at all Therefore when of two Bodies of equal magnitude one is lighter then the other it is manifest that the lighter Body hath in it more Vacuum then the other To say nothing of the Assumption concerning the endeavour of Bodies downwards which is not rightly assumed because the World hath nothing to do with Downwards which is a mere fiction of ours Nor of this that if al things tended to the same lowest part of the World either there would be no coalescence at all of Bodies or they would all be gathered together into the same place This onely is sufficient to take away the force of the argument that Aire intermingled with those his Atomes had served as well for his purpose as his intermingled Vacuum The third argument is drawn from this That Lightning Sound Heat and Cold do penetrate all Bodies except Atomes how solid soever they be But this reason except it be first demonstrated that the same things cannot happen without Vacuum by perpetual generation of Motion is altogether invalid But that all the same things may so happen shall in due place be demonstrated Lastly the fourth argument is set down by the same Lucretius in these Verses Duo de concursu corpora lata Si citò dissiliant nempe aer omne necesse est Inter corpora quod fuerat possidat Inane Is porro quamvis circum celerantibus auris Confluat haud poterit tamen uno tempore totum Compleri spatium nam primum quemque necesse est Occupet ille locum deinde omnia possideantur That is If two flat Bodies be suddenly pulled asunder of necessity the Air must come between them to fill all the space they left empty But with what celerity soever the Air flow in yet it cannot in one instant of time fill the whole space but first one part of it then successively all Which nevertheless is more repugnant to the opinion of Epicurus then of those that deny Vacuum For though it be true that if two Bodies were of infinite hardness and were joyned together by their Superficies which were most exactly plain it would be impossible to pull them asunder in regard it could not be done but by Motion in an instant yet if as the greatest of all Magnitudes cannot be given nor the swiftest of all Motions so neither the hardest of all hard Bodies it might be that by the application of very great force there might be place made for a successive flowing in of the Aire namely by separating the parts of the joyned Bodies by succession beginning at the outermost and ending at the innermost part He ought therefore first to have proved that there are some Bodies extreamly hard not relatively as compared with softer Bodies but absolutely that is to say infinitely hard which is not true But if we suppose as Epicurus doth that Atomes are indivisible and yet have small superficies of their own then if two Bodies should be joyned together by many or but one onely small superficies of either of them then I say this argument of Lucretius would be a firme demonstration that no two Bodies made up of Atomes as he supposes could ever possibly be pulled asunder by any force whatsoever But this is repugnant to daily experience And thus much of the arguments of Lucretius Let us now consider the arguments which are drawn from the experiments of later Writers 4 The first experiment is this That if a hollow vessel be thrust into water with the bottom upwards the water will ascend into it which they say it could not do unless the Aire within were thrust together into a narrower place and that this were also impossible except there were little empty places in the Aire Also that when the Aire is compressed to a certain degree it can receive no further compression its small particles not suffering themselves to be pent into less room This reason if the Aire could not pass through the Water as it ascends within the vessel might seem valid But it is sufficiently known that Aire will penetrate Water by the application of a force equal to the gravity of the Water If therefore the force by which the Vessel is thrust down be greater or equal to the endeavour by which the water naturally tendeth downwards the Aire will go out that way where the resistance is made namely towards the edges of the Vessel For by how much the deeper is the water which is to be penetrated so much greater must be the depressing force But after the Vessel is quite under water the force by which it is depressed that is to say the force by which the water riseth up is no longer encreased There is therefore such an equilibration between them as that the natural endeavour of the water downwards is equal to the endeavour by which the same water is to be penetrated to the encreased depth The second experiment is That if a concave Cylinder of sufficient length made of Glass that the experiment may be the better seen having one end open and the other close shut be filled with Quicksilver and the open end being stopped with ones finger be together with the finger dipped into a dish or other vessel in which also there is Quicksilver and the Cylinder be set upright we
which being done the Excentricity of the Earth will be cf. Seeing therefore the annual motion of the Earth is in the Circumference of an Ellipsis of which ♑ ♋ is the greater Axis ab cannot be the lesser Axis for ab and ♑ ♋ are equal Wherefore the Earth passing through a b will either pass above ♑ as through g or passing through ♑ will fall between c and a it is no matter which Let it pass therefore through g and let gl be taken equal to the straight line ♑ ♋ and dividing gl equally in i gi will be equal to ♑ ♋ il equal to f ♋ and consequently the point i will cut the Excentricity cf into two equal parts and taking ih equal to if hi will be the whole Excentricity If now a straight line namely the line ♎ i ♈ be drawn through i parallel to the straight lines ab and ed the way of the Sunne in Summer namely the Arch ♎ g ♈ will be greater then his way in Winter by 8 degrees and ¼ Wherefore the true Aequinoxes wil be in the straight line ♎ i ♈ and therefore the Ellipsis of the Earths annual motion will not pass through a g b l but through ♎ g ♈ l. Wherfore the annual motion of the Earth is in the Ellipsis ♎ g ♈ l and cannot be the Excentricity being salved in any other line And this perhaps is the reason why Kepler against the opinion of all the Astronomers of former time thought fit to bisect the Excentricity of the Earth or according to the Ancients of the Sunne not by diminishing the quantity of the same Excentricity because the true measure of that quantity is the difference by which the Summer Arch exceeds the Winter Arch but by taking for the Center of the Ecliptick of the great Orbe the point c neerer to f so placing the whole great Orbe as much neerer to the Ecliptick of the fixed Stars towards ♋ as is the distance between c i. For seeing the whole great Orbe is but as a point in respect of the immense distance of the fixed Starres the two straight lines ♎ ♈ and ab being produced both wayes to the beginnings of Aries and Libra will fall upon the same points of the Sphere of the fixed Stars Let therefore the Diameter of the Earth mn be in the plain of the Earths annual motion If now the Earth be moved by the Sunnes simple motion in the Circumference of the Ecliptick about the Center i this Diameter will bee kept alwayes parallel to itself and to the straight line gl But seeing the Earth is moved in the Circumference of an Ellipsis without the Ecliptick the point n whilst it passeth through ♎ ♑ ♈ will go in a lesser Circumference then the point m and consequently as soon as ever it begins to be moved it will lose its parallelisme with the straight line ♑ ♋ so that mn produced will at last cut the straight line gl produced And contrarily as soon as mn is past ♈ the Earth making its way in the internal Ellipticall line ♈ l ♎ the same mn produced towards m will cut lg produced And when the Earth hath allmost finished its whole circumference the same mn shall againe make a right angle with a line drawn from the center i a little short of the point from which the Earth began its motion And there the next yeare shall be one of the Aequinoctial points namely neer the end of ♠the other shall be opposite to it neer the end of ♓ And thus the points in which the Days and Nights are made equall doe every year fall back but with so slow a motion that in a whole year it makes but 51 first minutes And this relapse being contrary to the order of the Signes is commonly called the Praecession of the Aequinoxes Of which I have from my former Suppositions deduced a possible cause which was to be done According to what I have said concerning the cause of the Excentricity of the Earth and according to Kepler who for the cause thereof supposeth one part of the Earth to be affected to the Sunne the other part to be disaffected the Apogaeum Perigaeum of the Sunne should be moved every year in the same order and with the same velocity with which the Aequinoctiall points are moved and their distance from them should allwayes be the quadrant of a circle which seems to be otherwise For Astronomers say that the Aequinoxes are now the one about 28 degrees gone back from the first Star of Aries the other as much from the beginning of Libra So that the Apogaeum of the Sunne or the Aphelium of the Earth ought to be about the 28th degree of Cancer but it is reckoned to be in the 7th degree Seeing therefore we have not sufficient evidence of the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 that so it is it is in vaine to seek for the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 why it is so Wherefore as long as the motion of the Apogaeum is not observable by reason of the slownesse thereof and as long as it remaiues doubtful whether their distance from the Aequinoctiall points be more or lesse then a quadrant precisely so long it may be lawfull for me to thinke they proceed both of them with equall velocity Also I doe not at all meddle with the causes of the Excentricities of Saturne Jupiter Mars and Mercury Neverthelesse seeing the Excentricity of the Earth may as I have shewne be caused by the unlike constitution of the several parts of the Earth which are alternately turned towards the Sunne it is credible also that like effects may be produced in these other Planets from their having their Superficies of unlike parts And this is all I shall say concerning Sidereal Philosophy And though the causes I have here supposed be not the true causes of these Phaenomena yet I have demonstrated that they are sufficient to produce them according to what I at first propounded CHAP. XXVII Of Light Heat and of Colours 1 Of the immense Magnitude of some Bodies and the unspeakable Littleness of others 2 Of the cause of the Light of the Sun 3 How Light heateth 4 The generation of Fire from the Sunne 5 The generation of Fire from Collision 6 The cause of Light in Glow-wormes Rotten Wood and the Bolonian Stone 7 The cause of Light in the concussion of Sea-water 8 The cause of Flame Sparks and Colliquation 9 The cause why wet Hay sometimes burns of its own accord Also the cause of Lightning 10 The cause of the force of Gunpowder and what is to be ascribed to the Coals what to the Brimstone and what to the Nitre 11 How Heat is caused by Attrition 12 The distinction of Light into First Second c. 13 The causes of the Colours we see in looking through a Prisma of Glass namely of Red Yellow Blue and Violet Colour 14 Why the Moon and the Starres appear redder in the Horizon then in
long as there is sufficient heat in it but this ceasing it will shine no longer Also we find by experience that in the Glow-worm there is a certain thick humour like the Cristalline humour of the Eie which if it be taken out and held long enough in ones fingers and then be carried into the dark it will shine by reason of the warmth it received from the fingers but as soon as it is cold it will cease shining From whence therefore can these creatures have their Light but from lying all day in the Sun-shine in the hottest time of Summer In the same manner Rotten Wood except it grow rotten in the Sun-shine or be afterwards long enough exposed to the Sunne will not shine That this doth not happen in every Worm nor in all kinds of Rotten Wood nor in all Calcined Stones the cause may be that the parts of which those Bodies are made are different both in motion and figure from the parts of Bodies of other kinds 7 Also the Sea-water shineth when it is either dashed with the strokes of Oares or when a Ship in its course breaks strongly through it but more or less according as the Winde blows from different points The cause whereof may be this that the particles of salt though they never shine in the Salt-pits where they are but slowly drawn up by the Sunne being here beaten up into the aire in greater quantities and with more force are withall made to turn round and consequently to shine though weakly I have therefore given a possible cause of this Phaenomenon 8 If such matter as is compounded of hard little Bodies be set on fire it must needs be that as they flye out in greater or lesse quantities the Flame which is made by them will be greater or less And if the aethereal or fluid part of that matter fly out together with them their motion will be the Swifter as it is in Wood and other things which flame with a manifest mixture of Winde When therefore these hard particles by their flying out move the Eye strongly they shine bright and a great quantity of them flying out together they make a great shining Body For Flame being nothing but an aggregate of shining particles the greater the aggregate is the greater and more manifest will be the Flame I have therefore shewn a possible cause of Flame And from hence the cause appears evidently why Glass is so easily and quickly melted by the small Flame of a candle blown which will not be melted without blowing but by a very strong Fire Now if from the same matter there be a part broken off namely such a part as consisteth of many of the small particles of this is made a Spark For from the breaking off it hath a violent turning round and from hence it shines But though from this matter there fly neither Flame nor Sparks yet some of the smallest parts of it may be carried out as farre as to the Superficies and remain there as Ashes the parts whereof are so extremely small that it cannot any longer be doubted how farre Nature may proceed in Dividing Lastly though by the application of fire to this matter there fly little or nothing from it yet there will be in the parts an endeavour to Simple motion by which the whole Body will either be Melted or which is a degree of Melting Softned For all Motion has some effect upon all Matter whatsoever as has been shewn at the 3d Article of the 16th Chapter Now if it be softned to such a degree as that the stubborness of the parts be exceeded by their gravity then we say it is Melted otherwise Softned and made Pliant and Ductile Again the matter having in it some particles hard others aethereal or watery if by the application of fire these later be called out the former will thereby come to a more full contact with one another and consequently will not be so easily separated that is to say the whole Body will be made Harder And this may be the cause why the same Fire makes some things Soft others Hard. 9 It is known by experience that if Hay be laid wet together in a heap it will after a time begin to smoke and then burn as it were of it self The cause whereof seems to be this that in the Aire which is enclosed within the Hay there are those little Bodies which as I have supposed are moved freely with simple Motion But this Motion being by degrees hindred more and more by the descending moisture which at the last fils and stops all the passages the thinner parts of the Aire ascend by penetrating the water and those hard little Bodâ—â— being so thrust together that they touch and press one another acquire stronger motion till at last by the increased strength of this motion the watery parts are first driven outwards from whence appears Vapour and by the continued increase of this motion the smallest particles of the dryed Hay are forced out and recovering their natural simple Motion they grow Hot and Shine that is to say they are set on Fire The same also may be the cause of Lightning which happens in the hottest time of the yeare when the water is raised up in greatest quantity and carried highest For after the first Clouds are raised others after others follow them and being congeled above they happen whilest some of them ascend and others descend to fall upon another in such manner as that in some places all their parts are joyned together in others they leave hollow Spaces between them aud into these spaces the aethereall parts being forced out by the compressure of the Clouds many of the harder little Bodies are so pent together as that they have not the liberty of such motion as is naturall to the Aire Wherefore their endeavour growes more vehement till at last they force their way through the Clouds sometimes in one place sometimes in another and breaking through with great noise they move the aire violently striking our Eies generate Light that is to say they Shine And this Shining is that we call Lightning 10 The most common Phaenomenon proceeding from Fire and yet the most admirable of all others is the force of Gunpowder fired which being compounded of Niter Brimstone and Coles beaten small hath from the Coles its first taking fire from the Brimstone its nourishment and flame that is to say Light and motion and from the Niter the vehemence of both Now if a piece of Niter before it is beaten be laid upon a burning Cole first it melts and like water quencheth that part of the Cole it toucheth Then Vapor or Aire flying out where the Cole and Niter joyne bloweth the Cole with great swiftnesse and vehemence on all sides And from hence it comes to passe that by two contrary motions the one of the particles which go out of the burning Cole the other of those of the aethereall and watery substance
not a sufficient cause of their future Motion there being no other cause of Motion but Motion The cause therefore of such Restitution is in the parts of the Steel it self Wherefore whilest it remains bent there is in the parts of which it consisteth some motion though invisible that is to say some endeavour at least that way by which the restitution is to be made and therefore this endeavour of all the parts together is the first beginning of Restitution so that the impediment being removed that is to say the force by which it was held bent it will be restored again Now the motion of the parts by which this is done is that which I called Simple Motion or Motion returning into it self When therefore in the bending of a plate the ends are drawn together there is on one side a mutual compression of the parts which compression is one endeavour opposite to another endeavour and on the other side a divulsion of the parts The endeavour therefore of the parts on one side tends to the restitution of the plate from the middle towards the ends and on the other side from the ends towards the middle Wherefore the impediment being taken away this endeavour which is the beginning of restitution will restore the plate to its former posture And thus I have given a possible cause why some Bodies when they are bent Restore themselves again which was to be done As for Stones seeing they are made by the accretion of many very hard particles within the Earth which particles have no great coherence that is to say touch one another in small latitude and consequently admit many particles of aire it must needs be that in bending of them their internal parts will not easily be compressed by reason of their hardness And because their coherence is not firm as soon as the external hard particles are disjoyned the aethereal parts will necessarily break out and so the Body will suddenly be broken 13 Those Bodies are called Diaphanous upon which whilest the Beams of a lucid Body do work the action of every one of those Beams is propagated in them in such manner as that they still retain the same order amongst themselves or the inversion of that order and therefore Bodies which are perfectly Diaphanous are also perfectly homogeneous On the contrary an Opacous Body is that which by reason of its heterogeneous nature doth by innumerable reflexions and refractions in particles of different figures and unequal hardness weaken the Beams that fall upon it before they reach the Eie And of Diaphanous Bodies some are made such by Nature from the beginning as the substance of the Aire and of the Water and perhaps also some parts of Stones unless these also be Water that has been long congeled Others are made so by the power of Heat which congregates homogeneons Bodies But such as are made Diaphanous in this manner consist of parts which were formerly Diaphanous 14 In what manner Clouds are made by the motion of the Sunne elevating the particles of Water from the Sea and other moist places hath been explained in the 26th Chapter Also how Clouds come to be frozen hath been shewn above at the 7th Article Now from this that Aire may be enclosed as it were in Caverns and pent together more and more by the meeting of ascending and descending Clouds may be deduced a possible Cause of Thunder and Lightening For seeing the Aire consists of two parts the one Aethereal which has no proper motion of its own as being a thing divisible into the least parts the other Hard namely consisting of many hard Atomes which have every one of them a very swift simple motion of its own whilest the Clouds by their meeting do more and more straighten such Cavities as they intercept the Aethereal parts will penetrate and pass through their watry substance but the hard parts will in the mean time be the more thrust together and press one another and consequently by reason of their vehement motions they will have an endeavour to rebound from each other Whensoever therefore the compression is great enough and the concave parts of the Clouds are for the cause I have already given congeled into Ice the Cloud wil necessarily be broken this breaking of the Cloud produceth the first clap of Thunder Afterwards the Aire which was pent in having now broken through makes a concussion of the Aire without and from hence proceeds the roaring and murmur which follows and both the first Clap and the Murmur that follows it make that noise which is called Thunder Also from the same Aire breaking through the Clouds and with concussion falling upon the Eie proceeds that action upon our Eie which causeth in us a perception of that Light which we call Lightening Wherefore I have given a possible cause of Thunder and Lightening 15 But if the Vapours which are raised into Clouds do run together again into Water or be congeled into Ice from whence is it seeing both Ice and Water are heavy that they are sustained in the Aire Or rather what may the cause be that being once elevated they fall down again For there is no doubt but the same force which could carry up that Water could also sustain it there Why therefore being once carried up doth it fall again I say it proceeds from the same Simple Motion of the Sunne both that Vapours are forced to ascend and that Water gathered into Clouds is forced to descend For in the 21th Chapter and 11th Article I have shewn how Vapours are elevated and in the same Chapter and 5th Article I have also shewn how by the same motion Homogeneous Bodies are congregated Heterogeneous dissipated that is to say how such things as have a like nature to that of the Earth are driven towards the Earth that is to say what is the cause of the descent of Heavy Bodies Now if the action of the Sun be hindered in the raising of vapours and be not at all hindered in the casting of them down the Water will descend But a Cloud cannot hinder the action of the Sunne in making things of an earthly nature descend to the Earth though it may hinder it in making Vapours ascend For the lower part of a thick Cloud is so covered by its upper part as that it cannot receive that action of the Sunne by which Vapours are carried up because Vapours are raised by the perpetual fermentation of the Aire or by the separating of its smallest parts from one another which is much weaker when a thick Cloud is interposed then when the Skie is cleere And therefore whensoever a Cloud is made thick enough the water which would not descend before will then descend unless it be kept up by the agitation of the Winde Wherefore I have rendred a possible cause both why the Clouds may be sustained in the Aire and also why they may fall down again to the Earth which was propounded to
Hearer the Sound will come stronger then it would do through the open Aire And the cause not onley the possible but the certain and manifest cause is this that the Aire which is moved by the first breath and carried forwards in the Trunk is not diffused as it would be in the open Aire and is consequently brought to the eare almost with the same velocity with which it was first breathed out Whereas in the open Aire the first motion diffuseth it self every way into Circles such as are made by the throwing of a Stone into a standing water where the velocity grows less and less as the Undulation proceeds further and further from the beginning of its motion The second is this That if the Trunk be short and the end which is applyed to the mouth be wider then that which is applyed to the eare thus also the Sound will be stronger then if it were made in the open aire And the cause is the same namely that by how much the wider end of the Trunk is less distant from the beginning of the Sound by so much the less is the diffusion The third That it is easier for one that is within a Chamber to heare what is spoken without then for him that stands without to hear what is spoken within For the Windows and other inlets of the moved Aire are as the wide end of the Trunk And for this reason some creatures seem to hear the better because Nature has bestowed upon them wide and capacious Ears The fourth is this That though he which standeth upon the Sea shore cannot heare the Collision of the two neerest waves yet neverthess he hears the roaring of the whole Sea And the cause seems to be this that though the several collisions move the Organ yet they are not severally great enough to cause Sense whereas nothing hinders but that all of them together may make Sound 3 That Bodies when they are stricken do yeild some a more Grave others a more Acute Sound the cause may consist in the difference of the times in which the parts stricken and forced out of their places return to the same places again For in some Bodies the restitution of the moved parts is quick in others slow And this also may be the cause why the parts of the Organ which are moved by the Medium return to their rest again sometimes sooner sometimes later Now by how much the Vibrations or the reciprocal motions of the parts are more frequent by so much doth the whole Sound made at the same time by one stroke consist of more and consequently of smaller parts For what is Acute in Sound the same is Subtle in Matter and both of them namely Acute Sound and Subtle Matter consist of very small parts that of Time and this of the Matter it self The third distinction of Sounds cannot be conceived clearly enough by the names I have used of Clear and Hoarse nor by any other that I know and therefore it is needful to explain them by examples When I say Hoarse I understand Whispering and Hissing and whatsoever is like to these by what appellation soever it be expressed And Sounds of this kind seem to be made by the force of some strong Wind raking rather then striking such hard Bodies as it falls upon On the contrary when I use the word Clear I do not understand such a Sound as may be easily and distinctly heard for so Whispers would be Clear but such as is made by somewhat that is Broken and such as is Clamor Tinkling the Sound of a Trumpet c. and to express it significantly in one word Noise And seeing no Sound is made but by the concourse of two Bodies at the least by which concourse it is necessary that there be as well Reaction as Action that is to say one motion opposite to another it follows that according as the proportion between those two opposite motions is diversified so the Sounds which are made will be different from one another And whensoever the proportion between them is so great as that the motion of one of the Bodies be insensible if compared with the motion of the other then the Sound will not be of the same kind as when the Wind falls very obliquely upon a hard Body or when a hard Body is carried swiftly through the Aire for then there is made that Sound which I call a Hoarse Sound in Greek 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 Therefore the breath blown with violence from the mouth makes a Hissing because in going out it rakes the Superficies of the Lips whose reaction against the force of the breath is not Sensible And this is the cause why the Winds have that Hoarse Sound Also if two Bodies how hard soever be rubbed together with no great pressure they make a Hoarse Sound And this Hoarse Sound when it is made as I have said by the Aire raking the Superficies of a hard Body seemeth to be nothing but the dividing of the Aire into innumerable and very small Files For the asperity of the Superficies doth by the eminencies of its innumerable parts divide or cut in pieces the Aire that slides upon it 4 Noise or that which I call Clear Sound is made two wayes one by two Hoarse Sounds made by opposite motions the other by Collision or by the suddain pulling asunder of two Bodies whereby their small particles are put into commotion or being already in commotion suddenly restore themselves again which motion making impression upon the Medium is propagated to the Organ of Hearing And seeing there is in this Collision or divulsion an endeavour in the particles of one Body opposite to the endeavour of the particles of the other Body there will also be made in the Organ of Hearing a like opposition of endeavours that is to say of motions and consequently the Sound arising from thence will be made by two opposite motions that is to say by two opposite Hoarse Sounds in one and the same part of the Organ For as I have already said a Hoarse Sound supposeth the sensible motion of but one of the Bodies And this opposition of motions in the Organ is the cause why two Bodies make a Noyse when they are either suddenly stricken against one another or suddenly broken asunder 5 This being granted and seeing withall that Thunder is made by the vehement eruption of the Aire out of the cavities of congeled Clouds the cause of the great Noyse or Clap may be the suddain breaking asunder of the Ice For in this action it is necessary that there be not onely a great concussion of the small particles of the broken parts but also that this Concussion by being communicated to the Aire be carried to the Organ of Hearing make impression upon it And then from the first reaction of the Organ proceeds that first and greatest Sound which is made by the collision of the parts whilst they restore themselves And seeing there is