Hist Phil Early Modern
Hist Phil Early Modern PHI 022
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I ll lli I 11 I Ill LlJ II I LIJ Ill 391 l1 391 ll IJ ll lli I 391 II I Ily If NJ 1 III II Immanuel Kant Philosophy 22 Sp ng2008 G J Mattey I ll Iii W I ill Id W III ila LI 111 ill in ill ll W 11 Iii W in lla ill ill I ill 391 III II Vital Statistics Born 1724 Kenigsberg Prussia Died 1804 Kenigsberg Single Professor of Logic and Metaphysics at Kenigsberg University l l 39139 lj Iquot ll ll ll Ill ll ll ill lll ll III III l l 39139 lj lly ll 1 ll II I 1439 III III Important Events 173240 attended the Collegium Fridericianum 174046 attended Kenigsberg University 1747 published Thoughts on the True Estimation of Living Forces 174654 served as private tutor to families in K6nigsberg 1755 became private lecturer Privatdozent at Kenigsberg University in IQ 39139 lj Iquot ll ll ll Ill ll ll ill ill ll 391 III l l 39139 lj lly ll 1 ll II I 1439 III III Important Events cont 1755 published Universal Natural History and Theory of the Heavens 17551768 published a number of pre critical philosophical and scientific essays 1765 took a position as a sublibrarian at the Royal Palace Library 176970 turned down professorships at Erlangen and Jena 1770 appointed Ordinary Professor of Logic and Metaphysics at Kenigsberg University Important Events cont 1770 defended an inaugural dissertation On the Form and Principles of the Sensible and lnteligibe World 1781 published Critique of Pure Reason 1783 published Proegomena to any Future Metaphysics 39 1785 published Fundamental Principles of the Metaphysics of Morals Important Events cont 1787 published second edition of Critique of Pure Reason 1788 published Critique of Practical Reason 1790 published Critique ofthe Power of Judgment 39 1793 published Religion Within the Limits of Pure Reason 1794 censured by Frederick ll of Prussia 1796 retired from teaching I ll lli ll 11 ll Ill LlJ II VI LIJ Ill I ll 391 ll lj ll lli ll 391 II I III III NJ 1 III II Important Events cont 1884 died from senility and wasting of the 0 y Leibniz VS Descartes on Motion Philosophy 22N G J Mattey Leibniz s objection to Descartes s physics 39 In these slides we shall illustrate an objection raised by Leibniz against the physics of Descartes 39 Leibniz regarded Descartes as having made as simple error 39 Nothing is simpler than this proof Descartes fell into error here only because he had too much con dence in his own thoughts even when they were not suf ciently ripe Discourse 0n Metaphysics Article 17 Aristotle on falling bodies 39 Aristotle had de ned relative weight in terms of the speed at which bodies fall naturally 39 By lighter or relatively light we mean that one of two bodies endowed with weight and equal in bulk which is exceeded by the other in the speed of its natural downward movement On the Heavens Book IV Chapter 1 308a 30 39 So if body B moves downward naturally four times as fast as body A of the same size body B is four times heavier than body A Galileo on falling bodies 39 The speed of the fall of two bodies where there is no resistance from the medium is independent of their weight 39 Body B which is four times heavier than body A will fall from the same height at the same speed as does body A 39 This conclusion was supported by experimental evidence using balls rolled down inclined planes Uniform acceleration 39 Galileo also argued that falling bodies increase their speed at a uniform rate 39 Earlier scientists had held that the increase is a function of the distance traveled 39 Galileo argued that the increase is a function of the time taken in falling 39 The ratio of the distances covered by two falling bodies is equal to the ratio of the square of the times taken to fall those distances An example of acceleration 39 Suppose body A drops distance D in two seconds and body B drops distance d in one second dDt2T2 t2T2 D4d1 39 In other words body A covers four times the distance as is covered by body B although in only twice the amount of time A falls 4 times as far as B in twice the time 4un sin 25econds 1un in 1second Conservation of quantity of motion 39 According to Descartes there is a quantity which is constant throughout the history of the universe 39 This quantity is the quantity of motion 39 If one part of matter moves twice as fast as another which is twice as large we must consider that there is the same quantity of motion in each part Principles of Philosophy 11 36 39 The quantity of motion in an object is the speed times the size An Example 39 Let body A have a size of 1 and body B a size of four 39 Let the speed of A be twice the speed of B 39 Then the quantity of motion of A 1 X 2 2 39 The quantity of motion of B 4 X 1 4 39 Now apply this to the case of the falling bodies 39 A is moving twice as fast as B Speed of A 4 units of space in 2 seconds 42 2 Speed of B 1 unit of space in 1 second 11 1 A has twice the speed of B B has four times the size of A A 1 unit of size 4 units in 2 seconds 4 units 3 of size 1 unit in 1 second Rising and falling bodies 39 According to Leibniz the force of a falling body is equal to the force needed to raise the body back to the height it fell 39 This can be seen from the action of a pendulum Where discounting friction the weight rises to the height from which it fell 39 The same force is needed to lift a body of one unit of size to four units of distance as to raise a body of four units of size one unit of distance Force needed to lift A and B 4 units A of force 4 units of force The problem for Descartes 39 Suppose force quantity of motion 39 Then the quantity of the descending body A is half that of the descending body B 39 But it then follows that this force is enough to lift body A only two units of height 39 In that case force is lost and not simply transferred 39 So force should not be understood as quantity of motion Inequality of forces 2 units of force l k 4 units of force 2 units of force Conservation of force 39 Leibniz concluded that the only quantity that could function as force in Cartesian physics is not conserved 39 He thought he had a way of understanding force by which it is conserved 39 This quantity he called living force vis viva 39 There ensued a lengthy debate between the followers of Leibniz and those of Descartes and Newton about what exactly is conserved Instructor39s Notes Hume Treatise quotfell dead bom from the press Reviewed by Hume himself in the quotAbstractquot Three books understanding passions morals published later Introduction Begins with skeptical topic The inadequacy of current systems the disputes that rage on with victory to the eloquent with their extravagant hypotheses This creates a prejudice against metaphysical reasoning which is understood to be anything that is abstruse and that requires attention to be understood Yet the truth is deep and requires abstruse reasoning to recover it So we can39t take the easy and obvious route All sciences are traced to human nature even mathematics natural philosophy natural religion They are judged by human faculties which we need to be able to assess them More so regarding logic morals criticism aesthetics and politics Military analogy forget the outposts and march right up to the capital human nature itself The science of man is the only one which promises any security in the others The foundation for the science of man is quotexperience and observation Even though it comes after application to natural philosophy the experimental method has come after 100 years to moral philosophy Bacon is cited Interesting aside quotthe improvements in reason and philosophy can only be owing to a land of toleration and liberty Now the reason for the adoption of the experimental method the essence of the mind is as unknown as that of external bodies We must reject hypotheses Newton We should be satisfied with our ignorance once we realize it is unavoidable We cannot explain ultimate principles another Newtonian reference All other sciences share this defect What should be observed is the ordinary affairs of life It is here that quotexperimentsquot are to be quotcollected and compared From Part I 111 Impressions are distinguished from ideas in terms of force and liveliness Impressions include sensations passions emotions Then a second criterion is given they are original Ideas are faint copies of the originals There are a few instances when the two approach each other but quotthey are in general so very different that no on can make a scruple to rank them under distinct heads and assign a peculiar name to mark the difference A second division simple and complex ideas Simple ideas quotadmit of no distinction or separation Complex ideas have parts eg apple with quota particular color tastes and smell We perceive that they are not the same Locke ldeas resemble impressions in all but vivacity quotIdeas and impressions appear always to correspond to each other This is now qualified in that many complex ideas do not resemble an original New Jerusalem recollection of Paris However the resemblance is perfect with simple ideas This cannot be shown by enumeration but Hume challenges the reader to produce a counter example Regarding existence and cause and effect the impressions are the cause of the ideas quotThe full examination of this question is the subject of the present treatise We observe a constant conjunction and quotimmediately conclude that there is a great connection between our correspondent impressions and ideas and that the existence of the one has a considerable in uence upon that of the other Such a constant conjunction in such an infinite number of instances can never arise from chance but clearly proves a dependence of the impressions on the ideas or of the ideas on the impressions To tell which is cause and which effect we note that impressions come first Priority decides which is cause and which effect A supporting consideration is that one born without the use of a sense never has the corresponding ideas The missing shade of blue is quotso particular and singular that it is scarcely worth our observing and does not merit that we should alter our general maxim for it alone Another apparent exception is that we can form ideas from ideas But this is rather an explanation of the rule The impression is the first link of a chain To prove that there are no innate ideas philosophers appeal to impressions 112 Division of the Subject lmpressions are divided into those of sensation and re ection Impressions of sensation arise from unknown causes which should be treated by anatomists and natural philosophers Impressions of re ection arise from ideas quotin great measure Impression of pain gives rise to an idea of pain which in turn gives rise to impressions of quotdesire and aversion hope and fear which may properly be called impressions of re ection because derived from it The fact that the ideas give rise to impressions of re ection the passions is why he begins with them 113 Of the Ideas of the Memory and Imagination Memory and imagination are distinguished by relative vivacity Hume assigns these to two faculties Also the imagination is not so restrained as memory which preserves the original form The chief function of memory is to preserve order and position not the ideas themselves In ights of the fancy order goes right out the window An evident consequence of the division of ideas into simple and complex is that the components of complex ideas are separable which allows for recombination 114 Of the Connection or Association of Ideas We cannot account for the operations of the imagination unless we have some principle given the unlimited range of its activities The principle is a quotgentle force not so strong as memory but not chaotic Nature provides us with three bases for association Resemblance Contiguity Cause and Effect We observe that these are in play Cause and effect is the strongest force It can be near or remote and the more remote it is the more diluted its force It extends beyond actual change to powers especially power relations among people This kind of attraction is as important in the mental world as is gravitation in the natural The main result of association is the formation of complex ideas from simple ones Relations Modes Substances This is the same division as with Locke 115 Of Relations Relations are twofold natural vulgar and philosophical Distance is an example The vulgar is quotthat quality by which two ideas are connected together in the imagination and the one naturally explains the other The philosophical is where there is some proper basis of comparison There are seven sources of all philosophical relations Resemblance ldentity Relations of Space and Time Relations of quantity or number Relations of quality Relation of contrariety Relations of cause and effect both philosophical and natural 116 Of Modes and Substances We have no idea of substance There is no impression of it either of sensation or re ection which is really passions So the idea of substance is just a collection of simple ideas united by the imagination and assigned a same name We think there is something tying these together which allows us to add on subsequently discovered ideas This cannot happen with modes which are either dispersed in different subjects dance or have a uniting principle that is not regarded as the foundation of the complex idea beauty If a new idea is added you change the mode 117 Of Abstract ldeas Here Hume follows Berkeley You have to have a precise notion of the degree of quality and quantity The precise length of a line is not distinguishable and hence not different or separable from the line itself From Part 11 126 Of the Ideas of Existence and External Existence All impressions and ideas are conceived as existent So the idea of existence is conjoined with every perception or it just is the perception itself Anyone opposing this must point out the origin of the idea of entity There is no specific difference between an idea and external existence At best we quotform a relative idea of them without pretending to comprehend the related objects This will be explained later From Part 111 KEY QUOTATION quotAll kinds of reasoning consist in nothing but a comparison and a discovery of those relations either constant or inconstant which two or more objects bear to each other 132 131 Of Knowledge KEY POINT Knowledge and certainty confined to relations depending entirely on the ideas which we compare together Resemblance Contrariety eg existence and non existence Degrees in quality Proportions in quantity or number The first three are discoverable at first sight Some of the others are where the difference is very great Where the difference is very little we can only guess In between we have to use a more artificial manner Geometry cannot give us certainty but any error will be slight So only algebra and arithmetic do Abstract geometrical ideas are destroyed by the copy principle impressions are clear and precise and so cannot give rise to copies that are dark and intricate 132 Of Probability and of the Idea of Cause and Effect KEY POINT Reasoning is only required in the case of cause and effect The other three relations may be present or not while the ideas remain the same Distance is an example change of place is not a change in the idea We perceive identity and relations of time and place We reason from the existence or action of one object to that of another So apparent judgments of identity and distance of remote object involve cause and effect What is the origin of the idea of causation To reason justly using an idea we must understand it and to understand it we must uncover its origins to a primary impression quotThe examination of the impression bestows a clearness on the idea and the examination of the idea bestows a like cleamess on all our reasoning It is not a quality since cause and effect is a universal relation comprehending all specific qualities So it is a relation It is universally acknowledged that objects standing in the relation are contiguous and this is essential to the relation Not so universally acknowledged is priority Simultaneous causation is ruled out by a tricky argument which Hume says is of no importance But now we are at a stand All we observe is change in a given instance How could we say that impulse for example produces motion without invoking causation But there has to be something more necessary connection Fine but now what is the source of this impression Hume drops the direct survey and proceeds indirectly through two questions 1 Why do we find it necessary that the beginning of existence have a cause 2 Why do we conclude that particular causes have particular effects What is the nature of the inference drawn from one to the other and of the belief we have that there will be the particular effect 133 Why a Cause is Always Necessary KEY POINT The opinion that a cause is always necessary is based on observation and experience not on knowledge or any specific reasoning It is not intuitively certain because certainty is restricted to present objects that are compared A more general argument is that the ideas of a cause and a beginning of existence are separable l and so we see that there is no contradiction in supposing the latter without the former Various attempts to prove the principle have been fallacious Hobbes Clarke Locke All are based on the fallacy that in supposing there is no cause one is really assuming there is one e g Locke nothing can never be a cause Nor can it be proved from the idea of an effect So now the question is how reason and experience gives rise to such a principle But Hume decides to quotsinkquot this question in the second original question quotIt will perhaps be found in the end that the same answer will serve for both questions 134 Of the Component Parts of our Reasonings Concerning Cause and Effect KEY POINT All causal reasoning begins in an impression of sense or an idea of memory tantamount to an impression and makes a transition to an idea of an existence which produced it An example of history is given The effect is the letters in the history book present to us A regress argument is given to support the general point 135 Of the Impressions of the Senses and Memory KEY POINT The belief or assent given to the senses and memory as opposed to imagination is due entirely to the vivacity of the perceptions they present For sensation we do not know what the cause is and we draw assurance from coherence For memory it can easily be confused with imagination 136 Of the Inference from the Impression to the Idea KEY POINT In examining the inference we discover constant conjunction This is the missing third component of the relation of cause and effect discovered serindipitously by looking at the inference But how does this advance us toward an understanding of necessary connection quotIt seems evident at least at first sight that by this means we can never discover any new idea and can only multiply but not enlarge the objects of our mind From mere repetition no new idea can arise Maybe something will turn up later so we press on Does the experience produce the idea by means of the understanding or the imagination If it is by reason it would have to be by the principle that experienced instances resemble unexperienced ones and that the course of nature is always uniform But what does this principle rest upon It is not known It cannot be demonstrated since an exception can always be conceived It is not based on probable reasoning Probability requires this principle itself quotThe same principle cannot be both the cause and the effect of another and this is perhaps the only proposition concerning that relation which is either intuitively or demonstrably certain If you try to use explanatory reasoning you have to invoke cause and effect though perhaps under the guise of quotproductionquot This might seem like question begging by assuming a key part of Hume39s system so he produces a second argument Suppose that the production of an object in a single instance requires a power But it has been shown that the power does not reside in the qualities So how can we project from the appearance of the qualities that the power is there in other instances So reason fails us not only in discovering the ultimate connection of causes and effects but also in the extension beyond past experience We suppose a resemblance but we are never able to prove it The mind then in passing from an impression to an idea is determined by principles of association in the imagination There principles are not necessary or sufficient to explain ideas But they are the only general principles associating ideas resemblance contiguity causation Cause and effect as a natural relation is what produces a union of ideas that allows us to reason on causal principles 137 Of the Nature of ldea or Belief KEY POINT Belief is distinguished from conception by its liveliness Now the claim about the idea of existence comes into play Since every idea carries existence with it e g that of God the only difference in belief or non belief lies in the manner of conception With knowledge and demonstration a person is necessarily determined to conceive the idea in the particular way But with cause and effect the imagination is free Definition belief is quota lively idea related to or associate with a present impression But it is hard to explain in words how this works It is just something felt by the mind And it conforms to experience reading a romance novel vs reading history 138 Of The Causes of Belief KEY POINT The reason a lively idea is associated with a present impression is that a principle of association transfers the liveliness What principle is responsible for belief and how is vivacity bestowed on the idea The basic principle is that impressions bestow a share of their vivacity upon the ideas that are related to it The transition from impression and idea is so easy as not to be noticed This can be shown through quotexperimentsquot involving different kinds of natural relations 1 Resemblance picture of a friend that resembles him a lot inspires a vivid image of the friend and related passions But when the in uence is removed we consider the idea directly Roman Catholic uses of images show the same thing 2 Contiguity being in the vicinity of home makes for more vivid ideas than being very distant 3 Causation items once in the possession of saints shortens the causal route to them 4 Reasonings from cause and effect the claim about the in uence of relations follows directly from the description of causal reasoning every step of which quotappears to me sure and infallible Belief adds nothing so the enlivenment must be traced to the relation or association This quotwhole affairquot is now put into a quotfuller light It will be treated as quota question in natural philosophy which must be determined quotby experience and observation A present impression is presented and an internal belief is generated By what qualities are these extraordinary effects to be produced 1 How can an impression from which at its first appearance I can draw no conclusion become later an object of belief quotWhen I have had experience of its usual consequences We must in every case have observed the same impression in past instances and have found it to be constantly conjoined with some other impressions This is confirmed by such a multitude of experiments that it does not admit of the smallest doubt 2 The belief quotarises immediately without any new operation of the reason or imagination Of this I can be certain because I never am conscious of any such operation and find nothing in the subject on which it can be founded Definition of custom whatever quotproceeds from a past repetition without any new reasoning or conclusion So the belief is the outcome of custom a quotcertain truth quotWhen we are accustomed to see two impressions conjoined together the appearance or idea of the one immediately carries us to the idea of the other 3 Is anything else required Yes an impression since if you substitute an impression for an idea belief does not arise Bottom line quotI conclude upon the whole that belief is a more vivid and intense conception of an idea proceeding from its relation to a present impression Now the BIG conclusion quotThus all probable reasoning is nothing but a species of sensation It is not solely in poetry and music we must follow our taste and sentiment but likewise in philosophy When I am convinced of any principle it is only an idea which strikes more strongly upon me When I give the preference to one set of arguments above another I do nothing but decide from my feeling concerning the superiority of their in uence Objects have no discoverable connection together nor is it form any other principle but custom operating upon the imagination that we can draw any inference from the appearance of one to the existence of another This may operate insensibly as is the case of a person who stops short of crossing a river The transition is too fast for re ection and does not involve memory Still as it quotproceeds from experience and not from any primary connection between the ideas we must presume quota secret operation This confirms the fact that the principle of uniformity quotthat instances of which we have no experience must necessarily resemble those of which we have is not formed from reasoning since we rely on this principle without re ection and certainly quotwithout forming any principle concerning it or reasoning upon that principle Re ection may play a part in cases of quotother associations of objects which are more rare and unusualquot In fact sometimes re ection produces quotcustomquot in quotan oblique and arti cial mannerquot This is the case of quotknowledge of a particular cause merely by one experiment provided it be made with judgment and after a careful removal of all foreign and super uous circumstancesquot But custom is in fact drawn upon namely the custom that establishes the presupposed general principle quotthat like objects placed in like circumstances will always produce like e ectsquot So quotIn all cases we transfer our experience to instances of which we have no experience either expressly or tacitly either directly or indirectly quot An objection traced to the inexactitude of the terms used is now raised It is supposed to be based on an ambiguity in 39strong39 and 39lively39 but it really seems to be based on an ambiguity in the use of the term 39idea39 One has an idea of which one has forgotten the corresponding impression Now this idea leads us to believe that there was such an impression The belief would have to have come from the idea not the impression which seems to contradict Hume39s principle The answer is that force and vivacity of the belief are taken from the idea which quotsupplies the place of an impression and is entirely the same so far as regards our present purposequot This is because we consider it qua quota real perception of the mind of which we are intimately consciousquot rather than as quotthe representation of any absent objectquot As a perception the idea has a vivacity that can be transferred The resemblance of an idea idea of an idea is superior in force to quotthe loose conceptions of the imaginationquot We find in it a certain jenesciquoi which we cannot describe which makes us identify it as a memory 139 Of The Effects of Other Causes of Relations KEY POINT Resemblance and contiguity play a role in enlivening ideas which confirms the account of belief The theory in its novelty ought to be given justification from as many sources as possible and it ought to stand up to objections An objection resemblance and contiguity both meet the general description of principles of transmission So why don39t they produce belief The mind forms two systems of realities The first is from ideas of memory which are relatively vivid The second is from relating these to other ideas through the custom of cause and effect This is the role of judgment as in when 1 form an idea of Rome Now resemblance and contiguity play an enlivening role which is to quotassist that relation of cause and effect and infix the related idea with more force in the imaginationquot It can even enliven a feigned idea Still the in uence is quotvery feeble and uncertainquot It does not give us the persuasion of real existence The connections are variable and a matter of caprice We go so far as to adopt a general rule quotagainst proposing any assurances in those momentary glimpses of light which arise in the imagination from a feigned resemblance and contiguityquot But the causal relation is different it determines the mind39s transition quotwithout any choice or hesitationquot This can be turned into a proof of Hume39s doctrine If we can show how resemblance and contiguity have some effect augmenting the conviction and its vivacity it shows how belief is a matter of vivacity 1 Contiguity Pilgrims to the holy land are more zealous believers 2 Resemblance Hume poses the interesting case of communication of motion by impulse That this occurs cannot be proved since we can conceive of many quotconsistent and natura quot different outcomes So why do we expect motion upon impulse Because the effect resembles the cause quotResemblance then has the same or a parallel in uence with experience and as the only immediate effect of experience is to associate our ideas together it follows that all belief arises from the association of ideas according to my hypothesisquot Another example is the more vivid idea we get of the vast extent of the ocean by looking at it Credulity is also best explained by appeal to resemblance Experience teaches us the principles of human nature from which we gather the veracity of men as well as other things Yet we seldom regulate ourselves by it believing in all kinds of prodigious events This is explained by alleged resemblance between the ideas people have and the alleged facts which they report Looking at it in the other direction there is a lot of real incredulity among the vulgar about a future state The reason is that it bears so little resemblance to our current state It is not because death is off in the future since people are quite concerned about what will happen on earth after they die A good example is the way Catholics condemn massacres even while believing that the infidel will burn in hell quotAll we can say in excuse for this inconsistency is that they really do not believe what they affirm concerning a future state nor is there any better proof of it than the very inconsistencyquot Another point is that we can stand the stories of terror from the pulpit and in dramatic performances but we can39t stand fear and terror in real situations Education a second kind of custom An idea by being repeated becomes entrenched and easily distinguishable from quotany new and unusual ideaquot Sometimes it becomes so vivid that it overcomes what is the result of quotthe constant and inseparable union of causes and effectsquot Indoctrination could not produce belief it were the product of judgment Many other instances are given servants feeling the presence of the dead master people who become familiar with someone by hearing about them One half of all beliefs have a basis in education and they overwhelm beliefs from abstract reasoning and experience Because education is contrary to reason philosophers do not put it on a par with causal reasoning as it should be Footnote 14 Imagination is sometimes contrasted with memory based on its relative faintness When it is contrasted with reason it is the same faculty but now taken in a stricter sense excluding reasonings demonstrative and probable 1312 Of the Probability of Causes KEY POINT There are three sorts of probability of causes The first is due to not enough cases the second to contrary cases the third to cases that are not perfectly resembling Examination of the probability of chances in Section 11 not reprinted here helps us understand the probability of causes Chance is only a secret and concealed cause according to the philosophers All the several kinds of probability of causes have their origin in the association of ideas from present impressions 1 This association acquires force from more instances The inferior degrees of force are the degrees of probability 39The gradation therefore between probabilities to proofs is in many cases insensible and the difference between these kinds of evidence is more easily perceived in the remote degrees than in the near and contiguous As we mature however we cease to need a number of cases to build up the degree of assurance We can make an inference from a single case so long as it is quotduly prepared and examined Yet we do not claim certainty because of past instances of contrariety 2 The second species of probability is due to the fact that we do not smoothly accumulate cases without exceptions This obliges us to quotvary our reasoning on account of this uncertainty and take into consideration the contrariety of events Why does this contrariety exist The vulgar attribute it to a failure of causal in uence but philosophers point instead to minute and remote springs and principles as at least the possible causes of contrariety This is converted into certainty when it is seen upon close examination that when there are contrary effects there are contrary causes eg a grain of dust that stops the movements of a watch quotFrom the observation of several parallel instances philosophers form a maxim that the connection between all causes and effects is equally necessary and that its seeming uncertainty in some instances proceeds from the secret opposition of contrary causes Though they differ in explaining contrary causes the vulgar and the philosopher agree in the kind of inferences they draw First contrary cases lessen the perfection of the habit and so the vivacity of the idea This can be seen from common experience But this principle really has little in uence Habitual determination allows for no gap between the impression and idea But probable reasonings rarely are of this kind since we knowingly take the contrary instances into account And it happens even less frequently when there is an uninterrupted conjunction of objects So if the probability is to be based on habit it is only in an oblique manner This gives rise to the second species of probability The expectation that the future will resemble the past is habitual quotfull and perfect but when contrary instances present quota number of disagreeing images in a certain order of proportion the perfect habit quotis here broke into pieces and diffuses itself over all those images of which each partakes an equal share of the force and vivacity that is derived from the impulse Any of them may happen again and the vivacity is distributed in the same proportion of their past occurrence In this way the account of the probability of causes parallels the probability of chances The proportions in the past as they change increase or decrease the vivacity of ideas on each side quotEach new experiment is as a new stroke of the pencil which bestows an additional vivacity on the colors without either multiplying or enlarging the figure Some more subtle confirmations are given 1 All probabilities allow contrary possibilities These are based on actual occurrences in the past and so they may occur again in the future 2 The component parts differ in number and not in kind quotwhen we transfer the past to the future the known to the unknown every past experiment has the same weight and that it is only a superior number of them that can throw the balance on any side 3 There is reason to believe that the probability is a compounded effect A certain maxim is that when an effect decreases or increases in proportion to the number of parts the effect is compounded from the presence of these parts In the present case the vivacity of the belief varies with the number of experiments so we conclude that the number of experiments is the cause of the belief Now these three considerations are joined The bottom line is that the only explanation for them is in terms of increase or decrease of vivacity quotEach part presents a particular view and all these views uniting together produce one general view which is fuller and more distinct by the greater number of causes or principles from which it is derived The quantity and number of the parts do differ though Each presents a view that is quotfull and entire and comprehends the object in all its parts So since this doesn39t change only vivacity can explain the difference The argument is put in another way in terms of a dilemma Suppose our observations concur similar conditions similar results Then either we have many views of the same object or we have a greater degree of force in the same view The first is contradicted by experience as well as by the finite capacity of the mind So we are left with the second If the observations are contrary what else can happen than that quottheir in uence becomes mutually destructive and the mind is determined to the superior only with that force which remains after subtracting the inferior The vulgar might reject these considerations are too sophisticated and requiring too much work to understand But vulgar explanations are no good and the philosophers have yet to come up with anything better All you need though is to accept two principles and you will see that Hume39s system is correct 1 Nothing in an object considered in itself can give a reason to draw a conclusion about anything beyond it 2 Even after observation of constant conjunction of objects we have no reason to draw an inference beyond what we have experienced These principles are quotsufficiently convincing even with regard to our most certain reasonings from causation But for probable reasoning quotthey still acquire a new degree of evidence 1 ln probable reasoning it is not the object itself which is the basis of our conclusion since the uncertainty is about it If could draw a conclusion form the object there would be no need for causal reasoning 2 We can observe small differences in large probabilities This is not because we can detect them but because we apply general rules which tell us which is more likely than another There is a transference from small differences that we can observe to small differences that we cannot Species three of probability arises from analogy Where resemblance is weakened so is vivacity Resemblance is a necessary condition of causal reasoning but it comes in degrees 1314 Of the Idea of a Necessary Connection KEY POINT The impression of which the idea of necessary connection is a copy is the determination of the mind by custom to consider a second idea in the presence of a first perception and to do so more strongly because of its relation to the first object We are finally able to return to the main thread which concerns the nature of our idea of necessity after the detour through the way we make particular causal judgments The problem was to find the impression of which the idea is a copy Hume39s procedure now is to note that the idea of cause and effect is associated with necessary connection There are relations of contiguity and precedence When we reason we enlarge our view due to repetition There is nothing in the objects that makes any difference but there is a difference nonetheless in the later cases The difference is the determination of the mind by custom to produce a strong idea of the second object quotIt is this impression then or determination which affords me the idea of necessity Hume optimistically thinks the reader will find this somewhat obvious given the strength of his argument but he warns us not to think it as containing quotnothing extraordinary nor worthy of our curiosity But it is really quotone of the most sublime questions of philosophy namely that concerning the power and e icacy of causes where all the sciences seem so much interested So Hume will oblige the reader with a fuller account which he thinks will bolster his position More Hume discounts the previous attempts to give an account of the power of causes based on his denial of innate ideas and adoption of the copy principle In both the external and internal worlds all we perceive is constant conjunction There is also an argument based on the denial of abstract idea The idea of a power would have to come from that of specific cases of causality but we cannot find causality in the objects The problem with the earlier philosophers is that they misapplied the idea of power Hume then gives an account of their proper application We don39t get the idea from one instance only several instances Does repetition alone produce or discover power No since we cannot demonstrate that it exists And it produces nothing new So the source must be subjective quotthe observation of this resemblance produces a new impression in the mind which is its real model As this effect is the only product of resemblance it is identical to power or efficacy A remarkable comparison is made between the necessity of cause and effect and the necessity of mathematical truths which quotlies only in the act of the understanding by which we consider and compare these ideas This is the most violent paradox posed by the book Hume is worried that biases of the mind will prejudice his readers This bias is due to the quotgreat propensity of the mind quotto spread itself on external objects and to conjoin with them any internal impressions which they occasion and which always make their appearance at the same time that these objects discover themselves to our senses Secondary qualities are an example The objection will be that Hume reverses the order of dependence between thought and causes All he can answer is that the entrenched vie3w is meaningless Finally we get a definition of cause and effect after having proceeded preposterously by using the terms before defining them Philosophical relation comparison between ideas or natural relation association between ideas 1 quotAn object precedent and contiguous to another and where all the objects resembling the forer are placed in like relation of precedence and contiguity to those objects which resemble the latterquot 2 quotA cause is an object precedent and contiguous to another and so united with it that the idea of the one determines the mind to form the idea of the other and the impressio of the one to form a more lively idea of the otherquot Four corollaries 1 All causes are the same kind contrary to Aristotle 2 There is no difference between quotmoralquot and quotphysicalquot necessity Nor is there a Lockean distinction between power and its exercise 3 By the first definition of cause there is no absolute or metaphysical necessity that every beginning has a cause This is even more so on the second definition quotSuch an in uence on the mind is in itself perfectly extraordinary and incomprehensible nor can we be certain of its reality but from experience and observationquot 4 If we have no idea of an object we can never have reason that it exists This will be later applied to quotmatterquot and quotsubstancequot A full knowledge though is not requisite quotbut only of those qualities of it which we believe to existquot 1315 Rules by Which to Judge of Causes and Effects KEY POINT Because it is possible for anything to cause anything else general rules are needed to determine the philosophical relation of cause and effect 1 Contiguity in space and time 2 Priority 3 Constant union 4 Same cause always produces same effect And some corollaries and further rules This is all the logic we need in all philosophy moral or natural 141 quotOf Skepticism with Regard to Reasonquot KEY POINT If left to reason alone probability would decrease to nothing if we check our reasoning It is the strain of examination that keeps this from happening Reason is a natural cause of which truth is the natural effect But other causes may interfere which means that we cannot trust that the cause actually operated in a given case but must check whether it did So quotall knowledge degenerates into probability and this probability is greater or less according to our experience of the veracity or deceitfulness of our understanding and according to the simplicity or intricacy of the question This is seen in mathematics where checking increases the probability which itself quotis derived from the constant union of causes and effects according to past experience and observation 289 This holds in practical calculation as well Even if we control for simplicity and get it down to a single calculation it is questionable how high the sum must be before we have a mere probability But this fuzziness is intolerable as knowledge and probability are of different kinds so Hume comes down on the side of probability but without certainty of that So what is the foundation of probability In every judgment of knowledge or probability we ought to correct the first judgment about the object by a higher order judgment quotderived from the nature of our understanding e g whether we are wise and experienced or foolish etc Even with the greatest wisdom and experience one is susceptible for many errors So this provides a new standard of probability to correct the first one Reason now obliges us to add quota new doubt derived from the possibility of error in the estimation we make of the truth and fidelity of our faculties This doubt arises naturally Even if it is favorable to the judgment we made about our understanding it still increases the initial doubt and so weakens our first evidence Though it is hard to say how The process continues in infinitum But because the initial probability is a finite object it must eventually perish under infinite decrease quotAll the rules of logic require a continual diminution and at last a total extinction of belief and evidence 290 Does Hume assent to this argument and does it make him a skeptic holding quotthat all is uncertain and that our judgment is not in anything possessed of any measures of truth and falsehood No because nobody is a skeptic due to the quotabsolute and uncontrollable necessity of nature to determine us to judge There is no antagonist to someone who tries to defeat total skepticism What this argument does is to confirm the hypothesis concerning belief lf belief were quota simple act of thought without any peculiar manner of conception or the addition of force and vivacity it would be destroyed by the use of reason Since we continue to believe despite the argument belief is quota peculiar manner of conception which it is impossible for mere ideas and re ections to destroy 291 Hume has not yet said how belief is preserved however The same principles apply to the higher order judgments as apply to the original The answer is that after the first and second judgments the action of the mind becomes forced and unnatural When this occurs the in uence of the principles that govern all the judgments decreases in this case diminishing the effects of diminution So the animal spirits don39t function the same way We can see this diminution in action Metaphysics breeds skepticism because the strained imagination is not convinced by arguments that would work in history or politics We can39t grasp the wit of a tragic figure when we are gripped with emotion about them There seems to be a constant degree of force in the mind that can get tapped out quotBelief being a lively conception can never be entire where it is not founded on something natural and easy 292 Skepticism cannot be dismissed in any other way There is an anti skeptical argument to the effect that skepticism is parasitic on reason If its arguments are strong reason has credibility If they are weak then reason is not threatened But quotthis argument is not just 292 in that skepticism and reasoning would destroy each other Like boxers punching each other out until they both collapse skeptical arguments diminish reason39s authority which diminishes the force of the skeptical argument which still have enough punch to weaken reason39s authority some more and so on quotIt is happy therefore that nature breaks the force of all skeptical arguments in time and keeps them from having any considerable in uence on the understanding Were we to trust entirely to their self destruction that can never take place until they have first subverted all conviction and have totally destroyed human reason 142 quotOf Skepticism with Regard to the Senses KEY POINTS 1 What causes us to believe in the existence of body is the constancy and coherence of some perceptions which leads the mind to suppose the existence of enduring and independent bodies 2 Any investigation into the truth of this supposition exposes a contradiction in it which is overcome only by carelessness and inattention Hume begins by stating that the nature compels us to believe in the existence of body and that the only question is what causes this belief He approaches it through a commonly confounded distinction between the continued and the distinct existence of bodies Continued existence Bodies exist even when not present to the senses Distinct existence Bodies exist independently from the mind and the senses and externally to the senses The two imply each other Do we come by this belief from the senses reason or the imagination The senses cannot give rise to the belief in continued existence which is contradictory The only belief they could cause would be in distinct existence This could be done in two ways Impressions are images of something distinct Impressions are the distinct bodies The first is impossible quotA single perception can never produce the idea of a double existence but by some inference either of the reason or imagination The second way would require quota kind of fallacy and illusion We would have to have an impression of our mind and perceptions and see that the two are separate But the senses cannot reveal the self quotthe most profound metaphysics is required Moreover deceit seems impossible since the senses present perceptions as they really are Hume leaves the question of the possibility of the senses producing a belief in independent existence to the actuality It seems that we believe in external existence because we perceive bodies beyond our human body But this is impossible on Berkeleyan grounds we only perceive impressions secondary qualities are not external to the body and sight does not reveal distance or outness There is the further point that independence is not really determined by external situation Conclusion the senses do not give us the idea of distinct or continued existence or bodies Hume cites the primarysecondary quality distinction of the philosophers as confirmation of this view They are on the same footing quotas far as appears to the senses The vulgar have so strong a view of this that they think they can refute the philosophers just by quottheir feeling and experience There is also the similarity of these perceptions and pain Reason is not the cause of the beliefs since the arguments that appeal to reasoning are known to the very few The vulgar simply quotconfound perceptions and objects and attribute a distinct continued existence to the very things they feel or see So this quotentirely unreasonable sentiment must be based on something else A dilemma is given If perceptions and objects are confounded there is no inference If there is not then we cannot use causal reasoning as will be shown later Imagination is the only remaining candidate The way it works must be that some of our impressions have qualities that work hand in hand with qualities of the imagination quotIt will therefore be easy for us to discover these qualities by a comparison of the impressions to which we attribute a distinct and continued existence with those which we regard as internal and perishing The difference is not in the vulgar criteria of involuntariness or vivacity since these qualities are found in pains pleasures passions and affections The first viable quality of impressions regarding continued existence is constancy Impressions appear in the same order even after interruption of perception But constancy is not enough given that bodies change their positions when we are not perceiving them Still they preserve coherence which provides a foundation for quota kind of causal reasoning that establishes belief in their continued existence So how do constancy and coherence give rise to belief in continued existence Distinct existence will be a consequence of this Coherence is first An extended example is given 1 I hear quota noise as of a door turning upon its hinges If this noise is not from the door it contradicts all past experience 2 I see a porter moving toward me If the porter did not come up the stairs it contradicts all past experience according to which bodies have gravity and so he did not levitate to the next oor 3 I receive a letter If the letter did not traverse the sea and was not handed off at various posts and travel in different vehicles it contradicts past experience So the supposition of continued existence is the only one that will prevent these contradictions quotHere then I am naturally led to regard the world as something real and durable and as preserving its existence even when it is no longer present to my perception 297 Although this seems similar to causal reasoning it is not because there is nothing that is associated regularly in our minds but perceptions Moreover our supposition is actually more regular than our associated perceptions which custom could not account for We turn our heads and our perception does not present the body we were looking at before etc quotAny degree therefore of regularity in our perceptions can never be a foundation for us to infer a greater degree of regularity in some objects which are not perceived since this supposes a contradiction namely a habit which was never present to the mind So we need some other principles The principle invoked is that of a kind of inertia where quotthe imagination when set into any train of thinking is apt to continue even when its object fails it and like a galley put in motion by the oars carries on its course without any new impulse 297 The mind observes uniforrnities and quotnaturally continues until the train is as uniform as possible quotThe simple supposition of their continued existence suffices for this purpose Now Hume says that the kind of continued existence we get out of coherence is not nearly enough to support a system the continued existence of all bodies Constancy will be needed also to establish continued existence But because this quotwill lead me into a considerable compass of very profound reasoning he will first sketch his account of how it works and then draw consequences from it What happens in our minds is that our perceptions are interrupted yet constant to a certain degree It cannot be the same perception that re occurs after the interruption but rather an entirely new one This creates a con ict quota kind of contradiction in our imaginations we want to regard the perception as the same but we must regard it as different To overcome the con ict we quotdisguise as much as possible the interruption or rather remove it entirely by supposing that these interrupted perceptions are connected by a real existence of which we are insensible 298 This supposition of continued existence gets a force from memory and the tendency to regard perceptions of the same This results in belief which just is a vivid idea Now this system has only been sketched not justified To do this Hume needs to do several things 1 The problem arose because of the non identity of interrupted perceptions So he needs to say what the quotprinciple of identity is The principle is unvaried uninterruptedness since identity is temporal endurance 2 Explain why the resemblances in interrupted perceptions impel us to attribute identity to them Interrupted perceptions have only unvariedness They may be interrupted by a long period of time We think with the vulgar here there is no double existence involved but quotonly a single existence which I shall call indifferently object or perception according as it shall seem best to suit my purpose This is what the vulgar understand by shoe etc Resemblance greases the transitions in the imagination better than anything else Hume adopts the general rule quotthat whatever ideas place the mind in the same disposition or in similar ones are very apt to be confounded When there is an uninterrupted perception moments pass from one to another without any new perception being generated Can some other objects put us in the same disposition If so then by the general rule they are easily confused with identical objects The answer is easy quotrelatedquot objects can do the same thing quotThe thought slides along the succession with equal facility as if it considered only one object and therefore confounds the succession with identity 300 This is what happens in perception We have great constancy across interruption The result is an easy transition which produces quotalmost the same disposition of mind with that in which we consider one constant and uninterrupted perception It is therefore very natural for us to mistake the one for the other 300 3 Give an account of the propensity to unite the broken perceptions It is a certain principle that whenever there is con ict in the mind with the sentiments or passions there is uneasiness The converse holds as well what quotstrikes in with the natural propensities and either externally forwards their satisfaction or internally concurs with their movements is sure to give a sensible pleasure 301 So there is uneasiness in the present con ict between identity and interruptedness Which one is to give way The quotsmooth passage of our thought moves us toward identification so we give up the interruptedness Yet this does not seem satisfactory in that with long intervals the perceptions are obviously interrupted So it appears contradictory that they continue to exist without a mind To quotclear up this matter Hume will try to show that interruption in appearance of a perception dies not necessarily imply an interruption in its existence He does not challenge the claim that the objects are the perceptions So he needs to show A How a perception can be absent from the mind without ceasing to exist The mind is a bundle of perceptions and any one perception may be broken off from it without ceasing to exist B How can an idea become present to the mind return to it without being a new existence The broken off idea can be returned to the bundle at a later time quotThe same continued and uninterrupted being may therefore be sometimes present to the mind and sometimes absent from it without any real or essential change in the being itself 301 This just establishes the possibility of the continued existence of perceptions the lack of a contradiction But the mind has no access to this so it feigns continued existence 4 Explain the force and vivacity of the resulting idea This supposition of continued existence amounts to belief This is explained by the smoothness of the transition wherein the vivacity of the original impression is retained quotwithout any great diminution 302 The same holds for vivid ideas of memory Finally we extend this beyond sensation and memory because quotobjects which are perfectly new to us and of whose constancy and coherence we have no experience because of their resemblance to constant and coherent perceptions Now the exposition of the system has been completed It is more easily accepted than understood It is false that objects are identical after interruption given the supposition that they are perceptions So the belief in continued existence does not arise from reason but only from the imagination which is quotseduced into such an opinion based on resemblance and the propensity of the imagination There are two quotfictionsquot that of identity and that of continued existence A little philosophical re ection convinces us of the fallacy of the belief in continued existence This had to be uncovered because we knew already that belief in independent existence is false and it is the belief in continued existence which leads to the belief in independent existence Now we turn back to independent existence and account for the quotmany very curious opinions that come with it First experiments show that perceptions do not exist independently An example is pressing an eyeball which doubles the perceptions or varying our distance from the object The changes depend on us not the object This has led philosophers to distinguish between perceptions and objects The latter are uninterrupted and continue to exist Hume regards this as only a palliative remedy however quotIt contains all the difficulties of the vulgar system with some others that are peculiar to itself 303 1 The philosophical system has no primary recommendation either to the imagination or to reason First reason If we were to reason to the conclusion that objects exist independently of perceptions then it would have to be causally But causal reasoning is only based on resemblances between perceptions So we cannot reason our way to the existence of independent objects Second imagination How could the imagination make a transition to objects independent of perception Hume challenges the reader for an answer recognizing that it is hard to prove a negative The supposition of a mind independent object is abstract and not the proper subject for the imagination to work upon The common view that the objects are the perceptions is the primary one 2 The philosophical system gets all its in uence on the imagination from the vulgar system This is a consequence of the first claim In effect Hume is claiming that because we would not have arrived at the philosophical system without having had problems with the vulgar system it would have been an idle hypothesis if it did not solve some problem Why should we not simply reject continued existence except for the in uence of the imagination which feigns it A good summary is given on 304 Now we have a key claim The opinion that perceptions exist independently and continuedly and the opinion that they do not are in con ict Which system lays claim to us varies with our circumstances quotAs long as our attention is bent upon the subject the philosophical and studied principle may prevail but the moment we relax our thoughts nature will display herself and draw us back to our former opinion 304 Nature can even stop us in the middle of our thoughts No strained metaphysical conviction of the dependence of perception will eradicate our natural belief that they exist independently and continuedly The philosophical system is supposed to get us out of this fix through quota new hypothesis which seems to comprehend both these principles of reason and imagination 305 This is the double existence hypothesis allowing for the interruptedness and dependence of perception but the uninterruptedness and independence of objects This is no quotwin win compromise but rather a quotmonstrous offspring of contrary principles that cannot mutually destroy each other If we were fully convinced of either side we would have no need for the compromise Another advantage of the philosophical system is that so resembles the vulgar system that it is easily to slip from one to the other quotAccordingly we find that philosophers do not neglect this advantage but immediately upon leaving their closets mingle with the rest of mankind in those exploded opinions that our perceptions are our only objects and continue identically and uninterruptedly the same in all their interrupted appearances 305 Hume now remarks that the philosophical system depends on the imagination 1 External objects are supposed to resemble the internal perceptions This cannot be the result of causal reasoning It is based on the fact that all ideas of the imagination are borrowed from some preceding perception quotWe never can conceive anything but perceptions and therefore must make everything resemble them 305 2 This applies to particular cases We take a perception to resemble the object which caused it We add resemblance to cause and effect to quotcomplete the union which we have a strong propensity to do in every case This ends the account of the systems At this point Hume recognizes a skeptical sentiment being inclined quotat present no longer to repose faith in his imagination or what is commonly thought of as the senses The problem is with the quottrivial qualities of the fancy continuity and coherence being mobilized to produce false suppositions How can this quoteve lead to any solid and rational system The qualities have no perceivable connection to independent and continued existence The vulgar system is just inconsistent and all the philosophical system does is to invent a quotnew set of perceptions This is because we can only conceive particular ideas quotto be in their nature nothing but exactly the same with perceptions How can we place any confidence in this This doubt arises whenever we consider the matter The only way we can overcome it is through carelessness and inattention So Hume will grant that there is an internal and external world Section 4 Of the Modern Philosophy KEY POINT The fundamental principles of the modern philosophy that ideas of primary qualities resemble their objects while ideas of secondary qualities do not is mistaken There are two kinds of principles of the imagination those that quotare permanent irresistible and universal such as the customary transition from causes to effects and from effects to cause and the principles which are changeable weak and irregularquot 309 The changeable etc principles are subject to skepticism The former are quotthe foundation of all our thoughts and actions so that upon their removal human nature must immediately perish and go to ruin 309 Voice in the dark are thought to be other persons But some people apprehends specters instead The principles of the ancient philosophers are like specters in the dark quotThe modem philosophy pretends to be entirely free from this defect and to arise only from the solid permanent and consistent principles of the imagination What are the grounds of this pretension lts fundamental principle is that heat colors etc are impressions in the mind and do not resemble the objects causing them Its chief argument is that from relativity The external object remains the same while the impressions vary The conclusion drawn from this is quotas satisfactory as can possibly be imagined The key claim is that like effects have like causes Since some impressions do not resemble their originals and since there is no difference among these and other impressions none do quotWe conclude therefore that they are all of them derived from a like origin It seems that the principle of primary qualities alone being real follows by an quoteasy consequence These are quotextension and solidity with their different mixtures and modifications figure motion gravity and cohesion These are supposed to explain all physical phenomena Many objections may be lodged against the system but this one is in Hume39s opinion quotvery decisive Hume claims that if we grant that colors have no mind independent existence the so called primary qualities must also be Motion is resolved into extension and solidity But extension is resolved into quotperfectly simple and indivisible parts which must be colored or extended But color is excluded from real existence so they must be solid But to have an of solidity we must have an idea of objects which do not penetrate each other despite the utmost force But how is this to be composed Not of colors etc And extension depends on solidity as we have seen So the idea of solidity requires circular reasoning Though this argument quotwill appear entirely conclusive to everyone who comprehends it it is abstruse and could use some further explanation In effect Hume recapitulates the argument 311 Another problem is the impressions from which the idea of solidity is supposed to be derived It is supposed to come from feeling quotBut this method of thinking is more popular than philosophica 311 The feeling is different from the solidity First someone who cannot feel the table can see his hand to be supported by it Feeling is the outcome of a complex mechanical process Second impressions of touch are simple Yet to replicate the situation where two stones resist each other we would have to remove part of the impression which is impossible Third solidity is invariable while the feeling of resistance is variable The conclusion is that there is an opposition between causal reasoning and the senses The former excludes colors etc which then gets rid of the very objects that the senses indicate quothave a continued and independent existence The unstated conclusion is that the modern philosophy is mistaken Section 5 Of the lmmateriality of the Soul KEY POINT The notion of an immaterial soul is meaningless and given the account of causality in Part III the matter may be the cause of thought However this has no effect on religion The contradictions found with respect to external perceptions will surely extend to internal ones which are inclined to think are even more obscure Not so it at least contains no contradiction quotWhat is known concerning it agrees with itself and what is unknown we must be contented to leave so 312 What about the substance of the soul To have a resembling impression of it is impossible quotsince according to this philosophy it is not a substance and has none of the peculiar qualities or characteristics of a substance Speaking of actuality rather than possibility Hume asks what kind of impression it is supposed to be sensation or re ection pleasant or painful enduring or transient With no answer to these questions the proponent of substance may revert to abstract definitions such as quotsomething which may exist by itself But everything satisfies this definition Since whatever is different is distinguishable and whatever is distinguishable is separable by the imagination we can think of anything call it mode or accident existing separately quotThey are therefore substances as far as this definition explains a substance 313 So we should drop the dispute about the materiality or immateriality of the soul We have no idea of a substance and we do not need inhesion to understand the existence of a perception Hume then argues that the doctrine of the immateriality of the soul makes Spinozism a viable option Everything that is said about the soul as substance applies to Spinoza39s hyper substance Philosophers think that they have established that material things cannot be the cause of thought as this power cannot be discovered in them no matter how they are divided or organized But in fact no power can be discovered in anything Even God would have to be considered bereft of power Or if God is said to be the power moving everything Malebranche then God is the author of evil All we have is constant conjunction But there is constant conjunction between changes in the matter and changes in thought So we must think of changes in matter to be causes of changes in thought Finally there is the issue of the immortality of the soul Here philosophy must make an apology for herself Although the metaphysical arguments for the immortality of the soul are no good there are moral and analogical arguments which are good and which are not affected by the present system Section 6 Of Personal Identity Philosophers think we have a strong sense of the self and that each emotion etc confirms that it exists and continues to exist But they are contrary to experience Once again where is the impression To produce one would be to invite contradiction since it would have to remain the same all over our life while there is no constant and invariable impression Also all perceptions are distinct and so capable of existing on their own So how do they belong to the self All Hume can find are individual perceptions Annihilate them and you annihilate the self Anyone who does not have this impression quotthe rest of mankind is a bundle of perceptions in perpetual ux and rapid succession quotThe mind is a kind of theatre where several perceptions successively make their appearance pass repass glide away and mingle in an infinite variety of postures and situations There is no identity or simplicity here not even a theatre So why do we ascribe identity to successive perceptions Here we have to take the matter pretty deep and look into the identity of animals and plants since there is a great analogy here Once again the operative feature is the smoothness of transition Although identity applies only to what is invariable and uninterrupted when there is enough similarity we confuse identity with the notion of related objects I ll lli I 11 I Ill LlJ II I LIJ Ill 391 l1 391 ll IJ ll lli I 391 II I Ily If NJ 1 III II Immanuel Kant Philosophy 22 Sp ng2008 G J Mattey I ll Iii W I ill Id W III ila LI 111 ill in ill ll W 11 Iii W in lla ill ill I ill 391 III II Vital Statistics Born 1724 Kenigsberg Prussia Died 1804 Kenigsberg Single Professor of Logic and Metaphysics at Kenigsberg University l l 39139 lj Iquot ll ll ll Ill ll ll ill lll ll III III l l 39139 lj lly ll 1 ll II I 1439 III III Important Events 173240 attended the Collegium Fridericianum 174046 attended Kenigsberg University 1747 published Thoughts on the True Estimation of Living Forces 174654 served as private tutor to families in K6nigsberg 1755 became private lecturer Privatdozent at Kenigsberg University in IQ 39139 lj Iquot ll ll ll Ill ll ll ill ill ll 391 III l l 39139 lj lly ll 1 ll II I 1439 III III Important Events cont 1755 published Universal Natural History and Theory of the Heavens 17551768 published a number of pre critical philosophical and scientific essays 1765 took a position as a sublibrarian at the Royal Palace Library 176970 turned down professorships at Erlangen and Jena 1770 appointed Ordinary Professor of Logic and Metaphysics at Kenigsberg University Important Events cont 1770 defended an inaugural dissertation On the Form and Principles of the Sensible and lnteligibe World 1781 published Critique of Pure Reason 1783 published Proegomena to any Future Metaphysics 39 1785 published Fundamental Principles of the Metaphysics of Morals Important Events cont 1787 published second edition of Critique of Pure Reason 1788 published Critique of Practical Reason 1790 published Critique ofthe Power of Judgment 39 1793 published Religion Within the Limits of Pure Reason 1794 censured by Frederick ll of Prussia 1796 retired from teaching Leibniz VS Descartes on Motion Philosophy 22N G J Mattey Leibniz s objection to Descartes s physics 39 In these slides we shall illustrate an objection raised by Leibniz against the physics of Descartes 39 Leibniz regarded Descartes as having made as simple error 39 Nothing is simpler than this proof Descartes fell into error here only because he had too much con dence in his own thoughts even when they were not suf ciently ripe Discourse 0n Metaphysics Article 17 Aristotle on falling bodies 39 Aristotle had de ned relative weight in terms of the speed at which bodies fall naturally 39 By lighter or relatively light we mean that one of two bodies endowed with weight and equal in bulk which is exceeded by the other in the speed of its natural downward movement On the Heavens Book IV Chapter 1 308a 30 39 So if body B moves downward naturally four times as fast as body A of the same size body B is four times heavier than body A Galileo on falling bodies 39 The speed of the fall of two bodies where there is no resistance from the medium is independent of their weight 39 Body B which is four times heavier than body A will fall from the same height at the same speed as does body A 39 This conclusion was supported by experimental evidence using balls rolled down inclined planes Uniform acceleration 39 Galileo also argued that falling bodies increase their speed at a uniform rate 39 Earlier scientists had held that the increase is a function of the distance traveled 39 Galileo argued that the increase is a function of the time taken in falling 39 The ratio of the distances covered by two falling bodies is equal to the ratio of the square of the times taken to fall those distances An example of acceleration 39 Suppose body A drops distance D in two seconds and body B drops distance d in one second dDt2T2 t2T2 D4d1 39 In other words body A covers four times the distance as is covered by body B although in only twice the amount of time A falls 4 times as far as B in twice the time 4un sin 25econds 1un in 1second Conservation of quantity of motion 39 According to Descartes there is a quantity which is constant throughout the history of the universe 39 This quantity is the quantity of motion 39 If one part of matter moves twice as fast as another which is twice as large we must consider that there is the same quantity of motion in each part Principles of Philosophy 11 36 39 The quantity of motion in an object is the speed times the size An Example 39 Let body A have a size of 1 and body B a size of four 39 Let the speed of A be twice the speed of B 39 Then the quantity of motion of A 1 X 2 2 39 The quantity of motion of B 4 X 1 4 39 Now apply this to the case of the falling bodies 39 A is moving twice as fast as B Speed of A 4 units of space in 2 seconds 42 2 Speed of B 1 unit of space in 1 second 11 1 A has twice the speed of B B has four times the size of A A 1 unit of size 4 units in 2 seconds 4 units 3 of size 1 unit in 1 second Rising and falling bodies 39 According to Leibniz the force of a falling body is equal to the force needed to raise the body back to the height it fell 39 This can be seen from the action of a pendulum Where discounting friction the weight rises to the height from which it fell 39 The same force is needed to lift a body of one unit of size to four units of distance as to raise a body of four units of size one unit of distance Force needed to lift A and B 4 units A of force 4 units of force The problem for Descartes 39 Suppose force quantity of motion 39 Then the quantity of the descending body A is half that of the descending body B 39 But it then follows that this force is enough to lift body A only two units of height 39 In that case force is lost and not simply transferred 39 So force should not be understood as quantity of motion Inequality of forces 2 units of force l k 4 units of force 2 units of force
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