The Philosophical Works Of Descartes - YOGeBooks

The Philosophical Works of Descartes 9of reason, not for the purpose of resolvingthis or that difficulty of scholastic type2, but inorder that his understanding may light his willto its proper choice in all the contingencies oflife. In a short time he will see with amazementthat he has made much more progress thanthose who are eager about particular ends,and that he has not only obtained all that theydesire, but even higher results than fall withinhis expectation.2. scholae.

The Philosophical Works of Descartes 10Rule II.Only those objects should engage our attention,to the sure and indubitable knowledge of whichour mental powers3 seem to be adequate.Science in its entirety is true and evidentcognition. He is no more learned who hasdoubts on many matters than the man who hasnever thought of them; nay he appears to beless learned if he has formed wrong opinionson any particulars. Hence it were better not tostudy at all than to occupy one’s self with objectsof such difficulty, that, owing to our inabilityto distinguish true from false, we are forcedto regard the doubtful as certain; for in those3. ingenia.3

The Philosophical Works of Descartes 11matters any hope of augmenting our knowledgeis exceeded by the risk of diminishing it. Thusin accordance with the above maxim we rejectall such merely probable knowledge and makeit a rule to trust only what is completely knownand incapable of being doubted. No doubtmen of education may persuade themselvesthat there is but little of such certain knowledge,because, forsooth, a common failing of humannature has made them deem it too easy andopen to everyone, and so led them to neglectto think upon such truths; but I neverthelessannounce that there are more of these than theythink—truths which suffice to give a rigorousdemonstration of innumerable propositions,the discussion of which they have hitherto beenunable to free from the element of probability.Further, because they have believed that itwas unbecoming for a man of education toconfess ignorance on any point, they haveso accustomed themselves to trick out theirfabricated explanations, that they have ended

The Philosophical Works of Descartes 12by gradually imposing on themselves and thushave issued them to the public as genuine.But if we adhere closely to this rule we shallfind left but few objects of legitimate study.For there is scarce any question occurring inthe sciences about which talented men havenot disagreed. But whenever two men cometo opposite decisions about the same matterone of them at least must certainly be in thewrong, and apparently there is not even oneof them in the right; for if the reasoning ofthe second was sound and clear he would beable so to lay it before the other as finally tosucceed in convincing his understanding also.Hence apparently we cannot attain to a perfectknowledge in any such case of probable opinion,for it would be rashness to hope for morethan others have attained to. Consequently ifwe reckon correctly, of the sciences alreadydiscovered, Arithmetic and Geometry aloneare left, to which the observance of this rulereduces us.4

The Philosophical Works of Descartes 13Yet we do not therefore condemn thatmethod of philosophizing which others havealready discovered and those weapons of theschoolmen, probable syllogisms, which areso well suited for polemics. They indeed givepractice to the wits of youths and, producingemulation among them, act as a stimulus; and itis much better for their minds to be mouldedby opinions of this sort, uncertain though theyappear, as being objects of controversy amongthe learned, than to be left entirely to their owndevices. For thus through lack of guidance theymight stray into some abyss; but as long as theyfollow in their masters’ footsteps, though theymay diverge at times from the truth, they willyet certainly find a path which is at least in thisrespect safer, that it has been approved of bymore prudent people. We ourselves rejoice thatwe in earlier years experienced this scholastictraining; but now, being released from thatoath of allegiance which bound us to our oldmasters, and since, as becomes our riper years,

The Philosophical Works of Descartes 14we are no longer subject to the ferule, if wewish in earnest to establish for ourselves thoserules which shall aid us in scaling the heights ofhuman knowledge, we must admit assuredlyamong the primary members of our cataloguethat maxim which forbids us to abuse our leisureas many do, who neglect all easy quests andtake up their time only with difficult matters; forthey, though certainly making all sorts of subtleconjectures and elaborating most plausiblearguments with great ingenuity, frequently findtoo late that after all their labours they haveonly increased the multitude of their doubts,without acquiring any knowledge whatsoever.But now let us proceed to explain morecarefully our reasons for saying, as we did alittle while ago, that of all the sciences knownas yet, Arithmetic and Geometry alone arefree from any taint of falsity or uncertainty.We must note then that there are two waysby which we arrive at the knowledge of facts,viz. by experience and by deduction. We

The Philosophical Works of Descartes 15must further observe that while our inferencesfrom experience4 are frequently fallacious,deduction, or the pure illation of one thingfrom another, though it may be passed over,if it is not seen through5, cannot be erroneouswhen performed by an understanding that isin the least degree rational. And it seems tome that the operation is profited but little bythose constraining bonds by means of whichthe Dialecticians claim to control human reason,though I do not deny that that discipline maybe serviceable for other purposes. My reasonfor saying so is that none of the mistakes whichmen can make (men, I say, not beasts) are dueto faulty inference; they are caused merelyby the fact that we found upon a basis ofpoorly comprehended experiences, or thatpropositions are posited which are hasty andgroundless.4. experientias. This is a technical term used (like experimentum) for inductivearguments.5. si non videatur. Leibniz’s ms. adds in brackets ‘ea opus esse.’ Tr. ‘if it is not seen tobe necessary.’5

The Philosophical Works of Descartes 16This furnishes us with an evident explanationof the great superiority in certitude ofArithmetic and Geometry to other sciences.The former alone deal with an object so pureand uncomplicated, that they need make noassumptions at all which experience rendersuncertain, but wholly consist in the rationaldeduction of consequences. They are onthat account much the easiest and clearest ofall, and possess an object such as we require,for in them it is scarce humanly possible foranyone to err except by inadvertence. Andyet we should not be surprised to find thatplenty of people of their own accord preferto apply their intelligence to other studies, orto Philosophy. The reason for this is that everyperson permits himself the liberty of makingguesses in the matter of an obscure subjectwith more confidence than in one which is clear,and that it is much easier to have some vaguenotion about any subject, no matter what,

The Philosophical Works of Descartes 17than to arrive at the real truth about a singlequestion however simple6 that may be.But one conclusion now emerges out ofthese considerations, viz. not, indeed, thatArithmetic and Geometry are the sole sciencesto be studied, but only that in our search forthe direct road towards truth we should busyourselves with no object about which wecannot attain a certitude equal to that of thedemonstrations of Arithmetic and Geometry.6. facili.

The Philosophical Works of Descartes 18Rule III.In the subjects we propose to investigate, ourinquiries should be directed, not to what othershave thought 7, nor to what we ourselvesconjecture, but to what we can clearly andperspicuously behold and with certainty deduce;for knowledge is not won in any other way.To study the writings of the ancients is right,because it is a great boon for us to be ableto make use of the labours of so many men;and we should do so, both in order to discoverwhat they have correctly made out in previousages, and also that we may inform ourselvesas to what in the various sciences is still left for7. senserint.6

The Philosophical Works of Descartes 19investigation. But yet there is a great dangerlest in a too absorbed study of these workswe should become infected with their errors,guard against them as we may. For it is theway of writers, whenever they have allowedthemselves rashly and credulously to take up aposition in any controverted matter, to try withthe subtlest of arguments to compel us to goalong with them. But when, on the contrary, theyhave happily come upon something certainand evident, in displaying it they never fail tosurround it with ambiguities, fearing, it wouldseem, lest the simplicity of their explanationshould make us respect their discovery less, orbecause they grudge us an open vision of thetruth.Further, supposing now that all were whollyopen and candid, and never thrust upon usdoubtful opinions as true, but expoundedevery matter in good faith, yet since scarceanything has been asserted by any one manthe contrary of which has not been alleged

The Philosophical Works of Descartes 20by another, we should be eternally uncertainwhich of the two to believe. It would be nouse to total up the testimonies in favour ofeach, meaning to follow that opinion whichwas supported by the greater number ofauthors; for if it is a question of difficulty thatis in dispute, it is more likely that the truthwould have been discovered by few than bymany. But even though all these men agreedamong themselves, what they teach us wouldnot suffice for us. For we shall not, e.g. all turnout to be mathematicians though we know byheart all the proofs that others have elaborated,unless we have an intellectual talent that fitsus to resolve difficulties of any kind. Neither,though we have mastered all the argumentsof Plato and Aristotle, if yet we have not thecapacity for passing a solid judgment on thesematters, shall we become Philosophers; weshould have acquired the knowledge not of ascience, but of history.

The Philosophical Works of Descartes 21I lay down the rule also, that we must whollyrefrain from ever mixing up conjectures withour pronouncements on the truth of things.This warning is of no little importance. Thereis no stronger reason for our finding nothingin the current8 Philosophy which is so evidentand certain as not to be capable of beingcontroverted, than the fact that the learned,not content with the recognition of what isclear and certain, in the first instance hazardthe assertion of obscure and ill-comprehendedtheories, at which they have arrived merely byprobable conjecture. Then afterwards theygradually attach complete credence to them,and mingling them promiscuously with what istrue and evident, they finish by being unableto deduce any conclusion which does notappear to depend upon some proposition ofthe doubtful sort, and hence is not uncertain.But lest we in turn should slip into the sameerror, we shall here take note of all those8. vulgari.7

The Philosophical Works of Descartes 22mental operations by which we are able,wholly without fear of illusion, to arrive at theknowledge of things. Now I admit only two, viz.intuition and induction.By intuition I understand, not the fluctuatingtestimony of the senses, nor the misleadingjudgment that proceeds from the blunderingconstructions of imagination, but theconception which an unclouded and attentivemind gives us so readily and distinctly that weare wholly freed from doubt about that whichwe understand. Or, what comes to the samething, intuition is the undoubting conception ofan unclouded9 and attentive mind, and springsfrom the light of reason alone; it is more certainthan deduction itself, in that it; is simpler,though deduction, as we have noted above,cannot by us be erroneously conducted. Thuseach individual can mentally have intuition ofthe fact that he exists, and that he thinks; thatthe triangle is bounded by three lines only, the9. purae.

The Philosophical Works of Descartes 23sphere by a single superficies, and so on. Factsof such a kind are far more numerous thanmany people think, disdaining as they do todirect their attention upon such simple matters.But in case anyone may be put out by thisnew use of the term intuition10 and of otherterms which in the following pages I amsimilarly compelled to dissever from theircurrent meaning, I here make the generalannouncement that I pay no attention to theway in which particular terms have of late beenemployed in the schools, because it would havebeen difficult to employ the same terminologywhile my theory was wholly different. All that Itake note of is the meaning of the Latin of eachword, when, in cases where an appropriate termis lacking, I wish to transfer to the vocabularythat expresses my own meaning those that Ideem most suitable.This evidence and certitude, however, whichbelongs to intuition, is required not only in10. ‘Intuitus’ is but sparingly used in Descartes’ later writings.

The Philosophical Works of Descartes 24the enunciation of propositions, but also indiscursive reasoning of whatever sort. Forexample consider this consequence: 2 and 2amount to the same as 3 and 1. Now we needto see intuitively not only that 2 and 2 make 4,and that likewise 3 and 1 make 4, but furtherthat the third of the above statements is anecessary conclusion from these two.Hence now we are in a position to raisethe question as to why we have, besidesintuition, given this supplementary method ofknowing, viz. knowing by deduction, by whichwe understand all necessary inference fromother facts that are known with certainty. This,however, we could not avoid, because manythings are known with certainty, though not bythemselves evident, but only deduced fromtrue and known principles by the continuousand uninterrupted action of a mind11 that hasa clear vision of each step in the process. It isin a similar way that we know that the last link11. cogitationis.8

The Philosophical Works of Descartes 25in a long chain is connected with the first, eventhough we do not take in by means of one andthe same act of vision all the intermediate linkson which that connection depends, but onlyremember that we have taken them successivelyunder review and that each single one is unitedto its neighbour, from the first even to the last.Hence we distinguish this mental intuition fromdeduction by the fact that into the conceptionof the latter there enters a certain movementor succession, into that of the former theredoes not. Further deduction does not requirean immediately presented evidence suchas intuition possesses; its certitude is ratherconferred upon it in some way by memory.The upshot of the matter is that it is possibleto say that those propositions indeed whichare immediately deduced from first principlesare known now by intuition, now by deduction,i.e. in a way that differs according to our pointof view. But the first principles themselves aregiven by intuition alone, while, on the contrary,

The Philosophical Works of Descartes 26the remote conclusions are furnished only bydeduction.These two methods are the most certainroutes to knowledge, and the mind shouldadmit no others. All the rest should be rejectedas suspect of error and dangerous. But thisdoes not prevent us from believing mattersthat have been divinely revealed as being morecertain than our surest knowledge, since beliefin these things12, as13 all faith in obscure matters,is an action not of our intelligence14, but ofour will. They should be heeded also since, ifthey have any basis in our understanding, theycan and ought to be, more than all things else,discovered by one or other of the ways abovementioned, as we hope perhaps to show atgreater length on some future opportunity.12. ‘that faith of ours,’ Leibniz’s ms.13. ut quaecunque est de obscuris.14. ingenii.

The Philosophical Works of Descartes 27Rule IV.There is need of a method for finding out thetruth.So blind is the curiosity by which mortalsare possessed, that they often conducttheir minds along unexplored routes, havingno reason to hope for success, but merelybeing willing to risk the experiment of findingwhether the truth they seek lies there. As wellmight a man burning with an unintelligentdesire to find treasure, continuously roam thestreets, seeking to find something that a passerby might have chanced to drop. This is the wayin which most Chemists, many Geometricians,and Philosophers not a few prosecute their9

The Philosophical Works of Descartes 28studies. I do not deny that sometimes in thesewanderings they are lucky enough to findsomething true. But I do not allow that thisargues greater industry on their part, but onlybetter luck. But however that may be, it werefar better never to think of investigating truthat all, than to do so without a method. For itis very certain that unregulated inquiries andconfused reflections of this kind only confoundthe natural light and blind our mental powers.Those who so become accustomed to walk indarkness weaken their eye-sight so much thatafterwards they cannot bear the light of day.This is confirmed by experience; for how oftendo we not see that those who have never takento letters, give a sounder and clearer decisionabout obvious matters than those who havespent all their time in the schools? Moreoverby a method I mean certain and simple rules,such that, if a man observe them accurately, heshall never assume what is false as true, and willnever spend his mental efforts to no purpose,

The Philosophical Works of Descartes 29but will always gradually increase his knowledgeand so arrive at a true understanding of all thatdoes not surpass his powers.These two points must be carefully noted,viz. never to assume what is false as true, andto arrive at a knowledge which takes in allthings. For, if we are without the knowledgeof any of the things which we are capable ofunderstanding, that is only because we havenever perceived any way to bring us to thisknowledge, or because we have fallen intothe contrary error. But if our method rightlyexplains how our mental vision should

The Philosophical Works of Descartes ix Rule XIII. 138 Rule XIV. 153 Rule XV. 181 Rule XVI. 185 Rule XVII. 195 Rule XVIII. 200 Rule XIX. 213 Rule XX. 214 Rule XXI. 215 Discourse on Method 216 Prefatory Note to the Method. 217 Discourse on the Method of Rightly Conducting the Reason and Seeki