Descartes' Epistemology (Stanford Encyclopedia of Philosophy) Cite this entry Search the SEP • Advanced Search • Tools • RSS FeedTable of Contents• What's New• Archives• Projected ContentsEditorial Information• About the SEP• Editorial Board• How to Cite the SEP• Special CharactersSupport the SEPContact the SEP ©Metaphysics Research Lab,CSLI,Stanford University  Open access to the SEP is made possible by a world-wide funding initiative. Please Read How You Can Help Keep the Encyclopedia FreeDescartes' EpistemologyFirst published Wed Dec 3, 1997; substantive revision Thu Apr 14, 2005René Descartes (1596-1650) is widely regarded as the father ofmodern philosophy. His noteworthy contributions extend to mathematicsand physics. This entry focuses on his philosophical contributions inthe theory of knowledge. Specifically, the focus is on theepistemological project of Descartes' famous work, Meditations onFirst Philosophy.1. Conception of Knowledge—Internalist, Indefeasibilist, Methodist, Rationalist 1.1 Analysis of Knowledge 1.2 Internalism and Justification 1.3 Indefeasibility in Context 1.4 Methodist Approach 1.5 Innate Ideas 2. Methods: Foundationalism and Doubt 2.1 Foundationalism 2.2 Method of Doubt 3. First Meditation Doubting Arguments 3.1 Dreaming Doubt 3.2 Evil Genius Doubt 4. Cogito Ergo Sum 4.1 The First Item of Knowledge 4.2 But is it Knowledge? 5. Epistemic Privilege and Defeasibility 5.1 Our Epistemic Best: Clear and Distinct Perception and its Defeasibility 5.2 The Epistemic Privilege of Judgments About the Mind 6. Cartesian Circle 6.1 Establishing the Divine Guarantee of the C&D Rule 6.2 Circularity and the Broader Argument 7. Proving the Existence of the External Material World 7.1 The Case for the Externality of the Causes of Sensation 7.2 The Case for the Materiality of the Causes of Sensation 8. Proving that One is Not DreamingBibliographyOther Internet ResourcesRelated Entries1. Conception of Knowledge—Internalist, Indefeasibilist, Methodist, Rationalist1.1 Analysis of Knowledge Famously, Descartes defines knowledge in terms of doubt. Whiledistinguishing rigorous knowledge (scientia) and lessergrades of conviction (persuasio), Descartes writes: I distinguish the two as follows: there is conviction when thereremains some reason which might lead us to doubt, but knowledge isconviction based on a reason so strong that it can never be shaken byany stronger reason. (1640 letter, AT 3:64-65) Elsewhere, while answering a challenge as to whether he succeeds infounding such knowledge, Descartes writes: But since I see that you are still stuck fast in the doubts which Iput forward in the First Meditation, and which I thought I had verycarefully removed in the succeeding Meditations, I shall now expoundfor a second time the basis on which it seems to me that all humancertainty can be founded. First of all, as soon as we think that we correctly perceivesomething, we are spontaneously convinced that it is true. Now if thisconviction is so firm that it is impossible for us ever to have anyreason for doubting what we are convinced of, then there are nofurther questions for us to ask: we have everything that we couldreasonably want. … For the supposition which we are making here isof a conviction so firm that it is quite incapable of being destroyed;and such a conviction is clearly the same as the most perfectcertainty. (Replies 2, AT 7:144-45) These passages (and others) clarify that Descartes understands doubtas the contrast of certainty. As my certainty increases, my doubtdecreases; conversely, as my doubt increases, my certaintydecreases. The requirement that knowledge is to be based in complete,or perfect certainty, amounts to requiring a complete absence ofdoubt—an indubitability, or inability to undermineone's conviction. Descartes' methodic emphasis on doubt, rather thanon certainty, marks an epistemological innovation. This so-called‘method of doubt’ will be discussed below (Section 2). The certainty/indubitability of interest to Descartes is psychologicalin character, though not merely psychological—not simply aninexplicable feeling. It has also a distinctively epistemic character,involving a kind of rational insight. During moments of certainty, itis as if my perception is guided by “a great light in theintellect” (Med. 4, AT 7:59). This rational illuminationempowers me to “see utterly clearly with my mind's eye”;my feelings of certainty are grounded—indeed, “Isee a manifest contradiction” in denying the proposition ofwhich I'm convinced. (Med. 3, AT 7:36) Should we regard Descartes' account as a version of the justifiedtrue belief analysis of knowledge tracing back to Plato? Theabove texts (block quoted) are among Descartes' clearest statementsconcerning the brand of knowledge he seeks. Yet they raise questionsabout the extent to which his account is continuous with otheranalyses of knowledge. Prima facie, his characterizations imply ajustified belief analysis of knowledge—or in languagecloser to his own (and where justification is construed in terms ofunshakability), an unshakable conviction analysis. There's nostated requirement that the would-be knower's conviction is to betrue, as opposed to being unshakably certain. Istruth, therefore, not a requirement of Descartes' brand of strictknowledge? Many will balk at the suggestion. For in numerous texts Descarteswrites about truth, even characterizing a “rule for establishingthe truth” (Med. 5, AT 7:70, passim). It might therefore seemclear, whatever else is the case, that Descartes conceives ofknowledge as advancing truth. Without denying this, let me playdevil's advocate. It is not inconsistent to hold that we'repursuing the truth, even succeeding in establishingthe truth, and yet to construe the conditions of successwholly in terms of certainty; that is, to maintain that toestablish a proposition just is to perceive it withcertainty. Note again that Descartes says, of the perfect certainty heseeks, that it provides “everything that we could reasonablywant,” adding (in the same passage): What is it to us that someone may make out that the perception whosetruth we are so firmly convinced of may appear false to God or anangel, so that it is, absolutely speaking, false? Why should thisalleged “absolute falsity” bother us, since we neitherbelieve in it nor have even the smallest suspicion of it? (Replies 2,AT 7:144-45) On one reading of this remark, Descartes is explicitly embracing theconsequence of having defined knowledge wholly in terms of unshakableconviction: he's conceding that achieving the brand of knowledge heseeks is compatible with being—“absolutelyspeaking”—in error. If this is the correct reading, theinteresting upshot is that Descartes' ultimate aspiration is notabsolute truth, but absolute certainty. Of course, it should not beignored (on this reading) that these same remarks imply that achievingthis perfect certainty entails being unshakably convincedthat we're not in error, absolutely speaking. On a quite different reading of this passage, Descartes is clarifyingthat the analysis of knowledge is neutral not about truth, but aboutabsolute truth: he's conveying that the truth conditionrequisite to knowledge involves truth as coherence. A definitive interpretation of these issues has yet to gain generalacceptance in the literature. What is clear is that the brand ofknowledge Descartes seeks requires, at least, unshakably certainconviction.1.2 Internalism and Justification One way to divide up theories of justification is in terms of theinternalism-externalism distinction. Very roughly: a theory ofjustification is internalist insofar as it requires that thejustifying factors are accessible to the knower's conscious awareness;it is externalist insofar as it does not impose thisrequirement. Descartes' internalism requires that all justifying factors take theform of ideas. For he holds that ideas are, strictlyspeaking, the only objects of perception, or consciousawareness. Independent of this theory of ideas, Descartes' methodicaldoubts underwrite an assumption with similar force: for almost theentirety of the Meditations, hismeditator-spokesperson—hereafter referred to as the‘meditator’—adopts the assumption that his every thoughtis occurring in a dream. This assumption is tantamount to requiringthat justification come in the form of ideas. An important consequence of the account is that rigorous philosophicalinquiry must proceed via an inside-to-out strategy—a strategyDescartes assiduously follows, and which endures as a hallmark ofearly modern epistemologies. Ultimately, all judgments are grounded inan inspection of the mind's ideas. Philosophical inquiry is,properly understood, an investigation of ideas. The methodicalstrategy of the Meditations is designed to force the readerto adopt this mode of inquiry. 1.3 Indefeasibility in Context In characterizing knowledge as “incapable of beingdestroyed,” Descartes portrays knowledge asenduring. Our conviction must be, writes Descartes, “sostrong that it can never be shaken”; “so firm that it isimpossible for us ever to have any reason for doubting.”Descartes wants a brand of certainty/indubitability that is of thehighest rank, both in terms of degree anddurability. He wants knowledge that is utterlyindefeasible. This indefeasibility requirement implies more than mere stability. Awould-be knower could achieve stability simply by never reflecting onreasons for doubt. Referring to such a person, Descartes points outthat although a reason for “doubt may not occur to him, it canstill crop up if someone else raises the point or if he looks into thematter himself” (Replies 2, AT 7:141). Many readers conclude that Descartes' standards of justification aretoo high, for they have the consequence that almost nothing weordinarily count as knowledge measures up. Before jumping to thisconclusion, we should put the indefeasibility requirement intocontext. Descartes is a contextualist in the sense that he allows thatdifferent standards of justification are appropriate to differentcontexts. This is not merely to say the obvious: that depending on thecontext of inquiry, knowledge-worthy justification will sometimes beneeded, but other times not. It's to say something stronger: thatdepending on the context of inquiry, the standards of knowledge-worthyjustification might vary. For example, a contextualist might acceptthat ‘knowledge’-talkis equally appropriate whether one isdescribing the best achievements of empirical science, or the bestachievements of mathematics, while acknowledging that the former reston weaker standards of proof than the latter. This example ispotentially misleading, in that Descartes appears loath to count mereempirical evidence as knowledge-worthy justification. But upon rampingup the standard to what he finds minimally acceptable, the standardadmits of context dependent variation. Descartes' minimum standard targets the level of certainty arisingwhen the mind's perception is both clear anddistinct. (For Descartes, clarity contrasts withobscurity, and distinctness contrasts withconfusion.) He allows that judgments grounded in clear anddistinct perception are defeasible (at least, for those who've not yetread the Meditations). But he regularly characterizesdefeasible judgments at this level of certainty using terminology(e.g., ‘cognitio’ and its cognates) thattranslates well into the English ‘knowledge’ (and itscognates). In the context of inquiry at play in the Meditations,Descartes insists on indefeasibility. (Typically, he reserves the term‘scientia’ for this brand of knowledge, though heuses ‘cognitio’ and its cognates for eithercontext.) Descartes' aim is, once and for all, to lay a lastingfoundation for knowledge. To achieve this, he contends that we“cannot possibly go too far in [our] distrustful attitude”(Med. 1, AT 7:22). Better to have a standard that excludes sometruths, than one that justifies some falsehoods. An interesting thesis emerges—call it the ‘No AtheisticKnowledge Thesis’. Descartes maintains that though atheists arequite capable of impressive knowledge they are incapable of theindefeasible brand of knowledge he seeks: The fact that an atheist can be “clearly aware [clarecognoscere] that the three angles of a triangle are equal to tworight angles” is something I do not dispute. But I maintain that thisawareness [cognitionem] of his is not true knowledge[scientiam], since no act of awareness [cognitio]that can be rendered doubtful seems fit to be called knowledge[scientia]. Now since we are supposing that this individualis an atheist, he cannot be certain that he is not being deceived onmatters which seem to him to be very evident (as I fullyexplained). (Replies 2, AT 7:141) Hereafter, I refer to the indefeasible brand of knowledge Descartesseeks as ‘Knowledge’ (uppercase ‘K’).1.4 Methodist Approach How is the would-be Knower to proceed in identifying candidates forKnowledge? Distinguish particularist and methodist responses to thequestion. The particularist is apt to trust our prima facieintuitions regarding particular knowledge claims. These intuitionsmay then be used to help identify more general epistemic principles.The methodist, in contrast, is apt to distrust our primafacie intuitions. The preference is to begin with general principlesabout proper method. The methodical principles may then be used toarrive at settled, reflective judgments concerning particularknowledge claims. Famously, Descartes is in the methodist camp. Those who haphazardly“direct their minds down untrodden paths” are sometimes“lucky enough in their wanderings to hit upon some truth,”but “it is far better,” writes Descartes, “never tocontemplate investigating the truth about any matter than to do sowithout a method” (Rules 4, AT 10:371). Though it'sprima facie palpable that the earth is unmoved, and that ordinaryobjects (as tables and chairs) are just as just as theyseem, the newly emerging mechanist doctrines of the 17thcentury imply that such judgments are false. These kinds of casesunderscore the unreliability of our prima facie intuitions and theneed for a method by which to distinguish truth and falsity. Descartes' view is not that all our pre-reflective intuitionsare mistaken. He concedes that “no sane person has everseriously doubted” such particular claims as “that therereally is a world, and that human beings have bodies” (Synopsis,AT 7:16). His view is that pre-reflective judgments are likely to beill-grounded, even when true. The dialectic of the First Meditation features a confrontation betweenparticularism and methodism, with methodism emerging the victor. Forexample, the meditator (while voicing empiricist sensibilities) putsforward, as candidates for the foundations of Knowledge, such primafacie obvious claims as “that I am here, sitting by the fire,wearing a winter dressing-gown, holding this piece of paper in myhands, and so on”—particular matters “about whichdoubt is quite impossible,” or so it would seem (AT 7:18). Inresponse (and at each level of the dialectic), Descartes invokes hisown methodical principles to show that the prima facie obviousness ofsuch particular claims is insufficient to meet the burden ofproof.1.5 Innate Ideas Descartes' commitment to innate ideas places him in a rationalisttradition tracing back to Plato. Knowledge of the nature of realityderives from ideas of the intellect, not the senses. An important partof metaphysical inquiry therefore involves learning to think with theintellect. The allegory of the cave portrays this rationalist theme interms of epistemically distinct worlds. Plato likens what the sensesreveal to shadowy imagery on the wall of a poorly lit cave—towit, images of mere figurine beings; he likens what the intellectreveals to a world of fully real beings illuminated by brightsunshine. The metaphor aptly depicts our epistemic predicament, onDescartes' own doctrines. An important function of his methods is tohelp would-be Knowers redirect their attention from the confusedimagery of the senses, to the luminous world of the intellect's clearand distinct ideas. Further comparisons arise with Plato's doctrine of recollection. TheFifth Meditation meditator remarks—having applied Cartesianmethodology, thereby discovering innate truths within: “on firstdiscovering them it seems that I am not so much learning something newas remembering what I knew before” (Med. 5, AT 7:64). ElsewhereDescartes adds, of innate truths: [W]e come to know them by the power of our own native intelligence,without any sensory experience. All geometrical truths are of thissort—not just the most obvious ones, but all the others,however abstruse they may appear. Hence, according to Plato, Socratesasks a slave boy about the elements of geometry and thereby makes theboy able to dig out certain truths from his own mind which he had notpreviously recognized were there, thus attempting to establish thedoctrine of reminiscence. Our knowledge of God is of this sort. (1643letter, AT 8b:166-67) The famous wax thought experiment of the Second Meditation is supposedto illustrate (among other things) a procedure whereby to “digout” what is innate. The thought experiment purports to helpthe meditator achieve a “purely mental scrutiny,” moreeasily apprehending the innate idea of body. (Med. 2, AT 7:30-31)According to Descartes, our minds come stocked with a variety ofintellectual concepts—ideas whose content derives solely fromthe nature of the mind. This storehouse includes ideas in mathematics(e.g., number, line, triangle), logic (e.g., contradiction,necessity), and metaphysics (e.g., identity, substance,causality). Interestingly, Descartes holds that even our sensory ideasinvolve innate content. On his understanding of the new mechanicalphysics, bodies have no real properties resembling our sensory ideasof colors, sounds, tastes, and the like, thus implying that thecontent of such ideas draws from the mind itself. Unlike purelyintellectual concepts, however, the formation of these sensory ideasdepends on sensory stimulation. I suggest that on Descartes' officialdoctrine, ideas are innate insofar as their content derivesfrom the nature of the mind alone, as opposed to deriving from senseexperience. This characterization allows that both intellectual andsensory concepts draw on native resources, though not to the sameextent. Though the subject of rationalism in Descartes' epistemology deservescareful attention, the present essay generally focuses on Descartes'efforts to achieve indefeasible Knowledge. Relatively little attentionis given to his interesting doctrines of innateness, or, moregenerally, his ontology of thought. Further reading: On the internalism-externalism distinction,see Alston (1989) and Plantinga (1993). For a partly externalistinterpretation of Descartes, see Della Rocca (2005). For coherentistinterpretations of Descartes' project, see Frankfurt (1970) and Sosa(1997a). For a stability interpretation of Descartes, see Bennett(1990). On the indefeasibility of Knowledge, see Newman and Nelson(1999). On contextualism in Descartes, see Newman (2004). On themethodism-particularism distinction, see Chisholm (1982). OnDescartes' rationalism, see Adams (1975), Jolley (1990), and Newman(forthcoming).2. Methods: Foundationalism and Doubt Of his own methodology, Descartes writes: Throughout my writings I have made it clear that my method imitatesthat of the architect. When an architect wants to build a house whichis stable on ground where there is a sandy topsoil over underlyingrock, or clay, or some other firm base, he begins by digging out a setof trenches from which he removes the sand, and anything resting on ormixed in with the sand, so that he can lay his foundations on firmsoil. In the same way, I began by taking everything that was doubtfuland throwing it out, like sand … (Replies 7, AT 7:537) The theory whereby justified beliefs are best structured on an analogyto architecture traces back to ancient Greek thought—toAristotle, and to work in geometry. That Descartes' methodeffectively pays homage to Aristotle is, of course, welcome by hisAristotelian audience. However, he views Aristotle's foundationalistprinciples as incomplete, at least when applied to metaphysicalinquiry. I suggest that his method of doubt is intended to complementfoundationalism. The two methods are supposed to work in cooperation,as conveyed in the above quotation. Let's consider each method.2.1 Foundationalism The central insight of foundationalism is to organize one's beliefs inthe manner of a well structured, architectural edifice. Such anedifice owes its structural integrity to two kinds of features: a firmfoundation and a superstructure of support beamsfirmly anchored to the foundation. A system of justified beliefs mightbe organized by two analogous features: a foundation of unshakablefirst principles, and a superstructure of further propositionsanchored to the foundation via unshakable inference. Exemplary of a foundationalist system is Euclid's geometry. Euclidbegins with a foundation of first principles—definitions,postulates, and axioms or common notions—on which he then basesa superstructure of further propositions. Descartes' own designs formetaphysical Knowledge are inspired by Euclid's system: Those long chains composed of very simple and easy reasoning, whichgeometers customarily use to arrive at their mostdifficult demonstrations, had given me occasion to suppose that allthe things which can fall under human knowledge are interconnectedin the same way. (Discourse 2, AT 6:19). It would be misleading to characterize the arguments of theMeditations as unfolding straightforwardly according togeometric method. But Descartes maintains that they can bereconstructed as such, and he expressly does so at the end of theSecond Replies—providing a“geometrical” expositionof his central constructive steps, under the following headings:definitions, postulates, axioms or commonnotions, and propositions (AT 7:160ff). As alluded to above, the Meditations contains a destructivecomponent that Descartes likens to the architect's preparations forlaying a foundation. Though the component finds no analogue in themethod of the geometers, Descartes appears to hold that this componentis needed in metaphysical inquiry. The discovery of Euclid's firstprinciples (some of them, at any rate) is comparatively unproblematic:such principles as that things which are equal to the same thingare also equal to one another (one of Euclid's axioms) accord notonly with reason, but with the senses. In contrast, metaphysicalinquiry might have first principles that conflict with the senses: The difference is that the primary notions which are presupposed forthe demonstration of geometrical truths are readily accepted byanyone, since they accord with the use of our senses. Hence there isno difficulty there, except in the proper deduction of theconsequences, which can be done even by the less attentive, providedthey remember what has gone before. … In metaphysics bycontrast there is nothing which causes so much effort as making ourperception of the primary notions clear and distinct. Admittedly, theyare by their nature as evident as, or even more evident than, theprimary notions which the geometers study; but they conflict with manypreconceived opinions derived from the senses which we have got intothe habit of holding from our earliest years, and so only those whoreally concentrate and meditate and withdraw their minds fromcorporeal things, so far as possible, will achieve perfect knowledgeof them. (Replies 2, AT 7:156-57) Among Descartes' persistent themes is that such preconceived opinionscan have the effect of obscuring our mental vision of innateprinciples; that where there are disputes about first principles, itis not “because one man's faculty of knowledge extends morewidely than another's, but because the common notions are in conflictwith the preconceived opinions of some people who, as a result, cannoteasily grasp them”; whereas, “we cannot fail to know them[innate common notions] when the occasion for thinking about themarises, provided that we are not blinded by preconceivedopinions” (Prin. 1:49-50, AT 8a:24). These“preconceived opinions” must be “set aside,”says Descartes, “in order to lay the first foundations ofphilosophy” (1643 letter, AT 8b:37). Unless they are set aside,we're apt to regard, as first principles, the mistaken(though prima facie obvious) sensory claims that particularists findattractive. And mistakes in the laying of foundations weaken theentire edifice. Descartes adds:All the mistakes made in the sciences happen, in my view, simplybecause at the beginning we make judgements too hastily, and accept asour first principles matters which are obscure and of which we do nothave a clear and distinct notion. (Search, AT 10:526)Though foundationalism brilliantly allows for the expansion ofknowledge from first principles, Descartes thinks that a complementarymethod is needed to help us discover genuine first principles. Hedevises the method of doubt for this purpose—a method to help“set aside” preconceived opinions.2.2 Method of DoubtDescartes opens the First Meditation asserting the need “todemolish everything completely and start again right from thefoundations” (AT 7:17). In the architectural analogy, we canthink of bulldozers as the ground clearing tools of demolition. ForKnowledge building, Descartes construes sceptical doubts as the groundclearing tools of epistemic demolition. Bulldozers undermineliteral ground; doubt undermines epistemic grounds. Descartes' ultimate aims, however, are constructive. Unlike “thesceptics, who doubt only for the sake of doubting,” Descartesaims “to reach certainty—to cast aside the loose earth andsand so as to come upon rock or clay” (Discourse 3, AT6:28-29). Bulldozers are typically used for destructive ends, as aresceptical doubts. Descartes' methodical innovation is to employdemolition for constructive ends. Where a bulldozer's force overpowersthe ground, its effects are destructive. Where the ground's firmnessresists the bulldozer's force, the bulldozer might be usedconstructively—using it to reveal the ground asfirm. Descartes' innovation is to use epistemic bulldozers in thisway, using sceptical doubts to test the firmness of beliefs putforward as candidates for the foundations of Knowledge—testingtheir epistemic shakability. According to at least one prominent critic, this employment ofsceptical doubt is unnecessary and excessive. Writes Gassendi: There is just one point I am not clear about, namely why you did notmake a simple and brief statement to the effect that you wereregarding your previous knowledge as uncertain so that you could latersingle out what you found to be true. Why instead did you considereverything as false, which seems more like adopting a newprejudice than relinquishing an old one? This strategy made itnecessary for you to convince yourself by imagining a deceivingGod or some evil demon who tricks us, whereas it would surelyhave been sufficient to cite the darkness of the human mind or theweakness of our nature. (Objs. 5, AT 7:257-58; my italics) Gassendi singles out two features of methodic doubt—itsuniversal and hyperbolic character. In reply,Descartes remarks: You say that you approve of my project for freeing my mind frompreconceived opinions; and indeed no one can pretend that such aproject should not be approved of. But you would have preferred me tohave carried it out by making a ‘simple and briefstatement’—that is, only in a perfunctory fashion. Is it reallyso easy to free ourselves from all the errors which we have soaked upsince our infancy? Can we really be too careful in carrying out aproject which everyone agrees should be performed? (Replies 5, AT7:348)Evidently, Descartes holds that the universal andhyperbolic character of methodic doubt is helpful to itssuccess. Further appeal to the architectural analogy helps elucidatewhy. Incorporating these features enables the method to moreeffectively identify first principles. Making doubt universal andhyperbolic helps to distinguish genuine unshakability from the mereappearance of it. Consider first the universal character of methodic doubt. Inurging a universal doubt, Descartes does not mean simply that we're toapply doubt to all candidates for Knowledge. He is urgingsomething much stronger. He means that in the initial demolitionphase of the project we're to apply doubt collectively,undermining the candidates for the foundations of Knowledge all in onego: it is necessary “to demolish everything completely and startagain right from the foundations” (Med. 1, AT 7:17). Why mustdoubt be universal to this extent? Descartes offers the followinganalogy: Suppose [a person] had a basket full of apples and, being worried thatsome of the apples were rotten, wanted to take out the rotten ones toprevent the rot spreading. How would he proceed? Would he not begin bytipping the whole lot out of the basket? And would not the next stepbe to cast his eye over each apple in turn, and pick up and put backin the basket only those he saw to be sound, leaving the others? Injust the same way, those who have never philosophized correctly havevarious opinions in their minds which they have begun to store upsince childhood, and which they therefore have reason to believe mayin many cases be false. They then attempt to separate the falsebeliefs from the others, so as to prevent their contaminating the restand making the whole lot uncertain. Now the best way they canaccomplish this is to reject all their beliefs together in one go, asif they were all uncertain and false. They can then go over eachbelief in turn and re-adopt only those which they recognize to be trueand indubitable. (Replies 7, AT 7:481)Because one bad apple can spoil the whole bunch, the only sure meansto a rot-free basket is to discard the whole lot. What Descartesnotices is that even one falsehood that is mistakenly regarded as agenuine first principle—say, the belief that the senses arereliable, or that ancient authorities should betrusted—threatens to spread falsehood to other beliefs inthe system. A collective doubt helps avoid such mistakes. It ensuresthat the method only approves candidate first principles that areunshakable in their own right: it ensures that the appearance ofunshakability in a candidate is not owed to its logical relations toother principles, themselves not subjected to collective doubt. How is the hyperbolic character of methodic doubt supposed tocontribute to the method's success? The architectural analogy is againhelpful. Suppose that an architect is vigilant in employing auniversal/collective demolition in the destructive phase of herproject. Suppose, further, that she attempts to use bulldozers forconstructive purposes. A problem nonetheless arises. How big abulldozer is she to use? A light-duty bulldozer might be unable todistinguish a medium-sized boulder, and immovable bedrock. In bothcases, the ground would appear immovable. The solution liesin using not light-duty, but heavy-duty tools ofdemolition—the bigger the bulldozer, the better. The lesson isclear for the epistemic builder: the bigger the bulldozer, thebetter translates to the more hyperbolic the doubt, thebetter. A potential problem remains. Does not the problem of the“light-duty bulldozer” repeat itself? No matter how firmone's ground, it would be dislodged in the face of a yet biggerbulldozer. This raises the worry that there might not beunshakable ground, but only yet unshakenground. Descartes' goal of utterly indubitable epistemicground may simply be elusive. Perhaps the architectural analogy breaks down in a manner that servesDescartes well. For though there is no most-powerful literalbulldozer, perhaps epistemic bulldozing is not subject to thislimitation. Descartes seems to think that there is amost-powerful doubt—a doubt than which none morehyperbolic can be conceived. The Evil Genius Doubt (and equivalentdoubts) is supposed to fit the bill. If the method reveals epistemicground that stands fast in the face of a doubt this hyperbolic, then,as Descartes seems to hold, this counts as epistemic bedrock ifanything does. Hence the importance of the universal and hyperboliccharacter of the method of doubt. Gassendi's suggestion that we foregomethodic doubt in favor of a “simple and brief statement to theeffect that [we're] regarding [our] previous knowledge asuncertain” misses the intended point of methodic doubt. Before turning attention to the First Meditation demolition project, Iwant to address what I believe are significant misconceptions aboutthe method of doubt. Two of these are suggested in a passage from thepragmatist Peirce: We cannot begin with complete doubt. We must begin with all theprejudices which we actually have when we enter upon the study ofphilosophy. These prejudices are not to be dispelled by a maxim [viz.,the maxim that the philosopher “must begin with universaldoubt”], for they are things which it does not occur to uscan be questioned. Hence this initial skepticism will be amere self-deception, and not real doubt … A person may, it istrue, in the course of his studies, find reason to doubt what he beganby believing; but in that case he doubts because he has a positivereason for it, and not on account of the Cartesian maxim. Let us notpretend to doubt in philosophy what we do not doubt in ourhearts. (1955, 228f) It is a misconception that universal doubt is intended to result fromthe mere effort to adhere to the maxim—as if by sheer effort ofwill. To the contrary, Descartes introduces sceptical argumentsprecisely in acknowledgement that we need reasons fordoubt: I did say that there was some difficulty in expelling from our beliefeverything we have previously accepted. One reason for this is thatbefore we can decide to doubt, we need some reason for doubting; andthat is why in my First Meditation I put forward the principal reasonsfor doubt. (Replies 5, appendix, AT 9a:204) Another misconception is suggested by Peirce's reference to a“doubt in our hearts.” Distinguish two kinds of doubt, interms of two kinds of ways that doubt can defeat knowledge. Somedoubts purport to undermine one's conviction or belief—callthese ‘belief-defeating doubts’. Other doubtspurport to undermine one's justification (whether or not theyundermine belief)—call these‘justification-defeating doubts’. Descartes' aimof indefeasible Knowledge requires that he overcome both kinds ofdoubt, since either one defeats Knowledge. But the two kinds of doubtinvoke quite different doxastic attitudes. What Peirce calls a“doubt in our hearts” is suggestive of a belief-defeatingdoubt. Descartes' hyperbolic doubts, however, are intended asjustification-defeating. Part of what makes his doubtshyperbolic is that their extravagance renders them unlikelyto dislodge our existing beliefs. His doubts are supposed to help usto appreciate that even though we believe that 2+3=5, and believe thatwe're awake, and believe that there is an external world, wenonetheless lack indefeasible justification. A related misconception has Descartes calling not merely for doubt,but for disbelief or dissent. For example, Gassendi takes Descartes tobe urging us, quite literally, to “consider everything asfalse” (Objs. 5, AT 7:257-58). Thus read, Descartes is callingfor something even stronger than a belief-defeating doubt; he'scalling for a disbelief-inducing doubt. But surely the spirit (even ifnot always the letter) of Descartes' invocation to doubt is that weare to “hold back [our] assent from opinions which are notcompletely certain and indubitable just as carefully as [we] do fromthose which are patently false” (Med. 1, AT 7:18). Finally, a common misconception has it that the universality of doubtrenders inert the doubting hypotheses—and thus the entiremethod—since the hypotheses themselves are dubious in everycase. But this misses the point of the method: namely, to extend doubtuniversally to candidates for Knowledge, but not also to thevery tools for founding Knowledge. As Descartes concedes: “theremay be reasons which are strong enough to compel us to doubt, eventhough these reasons are themselves doubtful, and hence are not to beretained later on” (Replies 7, AT 7:473-74). Further reading: On foundationalism: for Descartes'treatment, see Discourse, First Meditation, and SeventhObjections and Replies; for its treatment by ancients, see Euclid(1956) and Aristotle (Posterior Analytics); by interpretersof Descartes, see Sosa (1997a) and Van Cleve (1979). On Cartesianinference, see Gaukroger (1989) and Hacking (1980). On methodicaldoubt: for Descartes' treatment, see Rules,Discourse, First Meditation, and Seventh Replies; bycommentators, see Frankfurt (1970), Garber (1986), Newman(forthcoming), Williams (1983), and Wilson (1978). On theanalysis-synthesis distinction (closed related to issues of doubt andmethodology): see the Second Replies (AT 7:155ff); see also Galileo(1967, 50f), Arnauld (L'Art de Penser, 4.2-3), Curley (1986),and Hintikka (1978).3. First Meditation Doubting Arguments3.1 Dreaming Doubt Historically, there are two distinct dream-related skepticaldoubts. The one doubt undermines the judgment that one ispresently awake—call this the ‘Now DreamingDoubt’. The other doubt undermines the judgment that one isever awake (i.e., in the way normally supposed)—callthis the ‘Always Dreaming Doubt’. A textual case can bemade on behalf of both formulations being raised in theMeditations. Though it will not be my aim to make thistextual case, we will consider both formulations. Both kinds of dream doubt appeal to some version of the thesis thatthe experiences we take as dreams are (at their best) qualitativelysimilar to what we take as waking—call this the‘Similarity Thesis’. The Similarity Thesis may beformulated in a variety of strengths. A strong Similarity Thesis mightcontend that some dreams are phenomenally indistinguishable fromwaking, even subsequent to waking-up; a weaker thesis might contendmerely that dreams seem similar to waking whilehaving them, but not upon waking. Debates about precisely howsimilar waking and dreaming can be, have raged for more than twomillennia. The tone of the debates suggests that the degree ofqualitative similarity may vary across individuals (or, at least,across their recollections of dreams). Granting suchvariation, dreaming doubts that depend on weaker versions of theSimilarity Theses are (other things equal) apt to be more persuasive.I want to consider a textually defensible formulation that isrelatively weak. (Note, however, that some texts suggest a strongthesis: “As if I did not remember other occasions when I havebeen tricked by exactly similar thoughts while asleep”(Med. 1, AT 7:19, my italics).) The relatively weak thesis I have in mind is this: that the similaritywe take to hold between waking and dreaming is sufficient to render itthinkable that a dream would seem realistic, evenwhen reflecting on it. As Descartes writes: “every sensoryexperience I have ever thought I was having while awake I can alsothink of myself as sometimes having while asleep” (Med. 6, AT7:77). This version of the Similarity Thesis is endorsable by thosewho never recollect dreams that seem (on hindsight) phenomenallyindistinguishable from waking; indeed, it's endorsable even by thosewho simply do not remember their dreams to any significant degree. This weak Similarity Thesis is sufficient to generate straightaway theNow Dreaming Doubt. Since it is thinkable that a dream wouldconvincingly seem as realistic (while having it) as mypresent experience seems, then, for all I Know, I am nowdreaming. Recall that Descartes' method requires only ajustification-defeating doubt, not a belief-defeating doubt. The doubtdoes its damage as long as I find it thinkable that a dreamwould seem this good. Descartes concedes that I might believethat I am awake—to wit, my belief might betrue. Descartes is only denying that I have indubitablecertainty: “there are never any sure signs by means ofwhich being awake can be distinguished from being asleep”(Med. 1, AT 7:19). The conclusion that I do not Know that I am now awake has widespreadsceptical consequences. For if I do not Know this, then neither do IKnow that I am now “holding this piece of paper in myhands”—nor do I Know anything suggested by externalsensation. For all I Know, the apparent sensible objects around me areplayers in a vivid dream. Much to-do has been made about whether dreaming arguments areself-refuting. According to an influential objection, SimilarityTheses presuppose that we can reliably distinguish dreams andwaking, yet the conclusion of dreaming arguments presupposes that wecannot. Therefore, if the conclusion of such arguments istrue, then the Similarity Thesis cannot be. By way of reply, someformulations of the thesis do make this mistake. Of presentinterest is whether all do—specifically, whetherDescartes makes the mistake. He does not. Interestingly, hisformulation of the Similarity Thesis presupposes only the truism thatwe do in fact distinguish dreaming and waking (never mind whetherreliably). He states his version of the thesis in terms of what wethink of as dreams, versus what we think of aswaking: “every sensory experience I have ever thought I washaving while awake I can also think of myself as sometimes havingwhile asleep” (Med. 6, AT 7:77). Does Descartes also put forward a second dreaming argument, the AlwaysDreaming Doubt? There is strong textual evidence to support this,though I'll not make a textual case here. The conclusion of the AlwaysDreaming Doubt can be generated from the very same Similarity Thesis,together with a further assumption. The further assumption is that,for all I Know, the processes producing what I take as waking are nomore veridical than those producing what I take as dreams. AsDescartes writes: [E]very sensory experience I have ever thought I was having whileawake I can also think of myself as sometimes having while asleep; andsince I do not believe that what I seem to perceive in sleep comesfrom things located outside me, I did not see why I should be any moreinclined to believe this of what I think I perceive whileawake. (Med. 6, AT 7:77) The aim of the Always Dreaming Doubt is not to undermine whether I amnow awake, but whether my sensation is produced by external objectseven assuming I am awake. For in the cases of both waking anddreaming, my cognitive access extends only to the productiveresult, but not the productive process. On whatbasis, then, do I conclude that the productive processes aredifferent—that external objects play more of a role in wakingthan in dreaming? For all I Know, both categories of experience areproduced by some subconscious faculty of my mind. As the meditatorsays: [T]here may be some other faculty [of my mind] not yet fully known tome, which produces these ideas without any assistance from externalthings; this is, after all, just how I have always thought ideas areproduced in me when I am dreaming. (Med. 3, AT 7:39)The sceptical consequences of the Always Dreaming Doubt are even moredevastating than those of the Now Dreaming Doubt. If I do not Knowthat “normal waking” experience is produced by externalobjects, then, for all I Know, all of my experiences might bedreams of a sort. For all I Know, there might not bean external world. For my best evidence of an external world derivesfrom my preconceived opinion that external objects produce mysensation: All these considerations are enough to establish that it is notreliable judgement but merely some blind impulse that has made mebelieve up till now that there exist things distinct from myself whichtransmit to me ideas or images of themselves through the sense organsor in some other way. (Med. 3, AT 7:39-40) The two dreaming doubts are parasitic on the same Similarity Thesis,though their sceptical consequences differ. The Now Dreaming Doubtraises the universal possibility of delusion: for any one ofmy sensory experiences, it is possible (for all I Know) that theexperience is delusive. The Always Dreaming Doubt raises thepossibility of universal delusion: it is possible (for all IKnow) that all my sensory experiences are delusions (say, from aGod's-eye perspective). In either case, dreaming related doubts aresupposed to help clarify that external sense, per se, isincapable of grounding Knowledge of external things.3.2 Evil Genius Doubt Though dreaming doubts do significant demolition work, they arelight-duty bulldozers relative to Descartes' most power scepticaldoubt. What further judgments are left to be undermined? Immediatelyfollowing the First Meditation discussion of dreaming, the meditatortentatively concludes that dreaming motivated doubts undermine theresults of empirical disciplines—“physics, astronomy,medicine,” and the like. Whereas: [A]rithmetic, geometry and other subjects of this kind, which dealonly with the simplest and most general things, regardless of whetherthey really exist in nature or not, contain something certain andindubitable. For whether I am awake or asleep, two and three addedtogether are five, and a square has no more than four sides. It seemsimpossible that such transparent truths should incur any suspicion ofbeing false. (Med. 1, AT 7:20) In the final analysis, Descartes holds that such transparenttruths—along with demonstrable truths, and many judgments ofinternal sense—are indeed Knowable. To become actuallyKnown, however, they must be unshakably grounded in the facethe most powerful doubts. The stage is thus set for the introductionof this most powerful doubt. The most famous rendering of Descartes' most hyperbolic doubt takesthe form of the Evil Genius Doubt. Suppose I am the creation of apowerful but malicious being. This “evil genius” (ordeceiving “God, or whatever I may call him,” AT 7:24) hasgiven me flawed cognitive faculties, such that I am in error evenabout epistemically impressive matters—even the simple mattersthat seem supremely evident. The suggestion is unbelievable, but notunthinkable. It is intended as a justification-defeating doubt thatundermines our judgments about even the most simple and evidentmatters. Many readers of Descartes assume that the Evil Genius Doubt draws itssceptical force from the “utmost power” attributed to thedeceiver. This is to misunderstand Descartes. He contends that anequally powerful doubt may be generated on the oppositesupposition—namely, the supposition that I am not thecreature of an all-powerful being: Perhaps there may be some who would prefer to deny the existence of sopowerful a God rather than believe that everything else is uncertain.… yet since deception and error seem to be imperfections, theless powerful they make my original cause, the more likely it is thatI am so imperfect as to be deceived all the time. (Med. 1, AT7:21). Descartes makes essentially the same point in a parallel passage ofthe Principles: [W]e have been told that there is an omnipotent God who created us.Now we do not know whether he may have wished to make us beings of thesort who are always deceived even in those matters which seem to ussupremely evident … We may of course suppose that our existencederives not from a supremely powerful God but either from ourselves orfrom some other source; but in that case, the less powerful we makethe author of our coming into being, the more likely it will be thatwe are so imperfect as to be deceived all the time. (Prin.1:5, AT 8a:6) Descartes' official position is that the Evil Genius Doubt is merelyone among multiple hypotheses that can motivate the more generalhyperbolic doubt. Fundamentally, the doubt is about my cognitivenature—about the possibility that my mind is flawed. Descartesconsistently emphasizes this theme throughout theMeditations: God could have given me a nature such that I was deceivedeven in matters which seemed most evident. (Med. 3, AT 7:36) I can convince myself that I have a natural disposition to go wrongfrom time to time in matters which I think I perceive as evidently ascan be. (Med. 5, AT 7:70) I saw nothing to rule out the possibility that my natural constitutionmade me prone to error even in matters which seemed to me mosttrue. (Med. 6, AT 7:77) What underwrites the doubt is not a specific story about how I got mycognitive wiring; it's the realization—regardless thestory—that I can worry that my cognitive wiring isflawed. Elsewhere, I have suggested that we name the underlying doubt‘Meta-Cognitive Doubt’, to make clear that it isfundamentally about the implications of having a flawed cognitivenature, not the implications of an omnipotent creator. Even so, Ishall regularly speak in terms of the evil genius (followingDescartes' lead), as a kind of mnemonic for the more general doubtabout our cognitive nature. Having introduced the Evil Genius Doubt, the First Meditation programof demolition is not only hyperbolic butuniversal. As the meditator remarks, I “am finallycompelled to admit that there is not one of my former beliefs aboutwhich a doubt may not properly be raised” (Med. 1, AT 7:21). Aswill emerge, the early paragraphs of the Third Meditation clarify afurther nuance of the Evil Genius Doubt—a nuance consistentlyobserved thereafter. Descartes clarifies there that the Evil GeniusDoubt operates in an indirect manner, a topic to which we return (in Section 5.1).Further reading: On Descartes' sceptical arguments, seeBouwsma (1949), Curley (1978), Newman (1994), Newman and Nelson(1999), Williams (1986 and 1995). For a contrary reading of the EvilGenius Doubt, see Gewirth (1941) and Wilson (1978). For a more generalphilosophical treatment of dreaming arguments, see Dunlap (1977).4. Cogito Ergo Sum 4.1 The First Item of Knowledge Famously, Descartes puts forward a very simple candidate as the“first item of knowledge.” The candidate is suggested bymethodic doubt—by the very effort at thinking all my thoughtsmight be mistaken. Early in the Second Meditation, Descartes has hismeditator observe: I have convinced myself that there is absolutelynothing in the world, no sky, no earth, no minds, no bodies. Does itnow follow that I too do not exist? No: if I convinced myself ofsomething then I certainly existed. But there is a deceiver of supremepower and cunning who is deliberately and constantly deceiving me. Inthat case I too undoubtedly exist, if he is deceiving me; and let himdeceive me as much as he can, he will never bring it about that I amnothing so long as I think that I am something. So after consideringeverything very thoroughly, I must finally conclude that thisproposition, I am, I exist, is necessarily truewhenever it is put forward by me or conceived in my mind. (Med. 2, AT7:25) As the canonical formulation has it, I think therefore I am(Latin: cogito ergo sum; French: je pense, doncje suis)—a formulation which does not expressly arise inthe Meditations. Descartes regards the ‘cogito’ (as I shall referto it) as the “first and most certain of all to occur to anyonewho philosophizes in an orderly way” (Prin. 1:7, AT8a:7). Testing the cogito with methodic doubt is supposed tohelp me appreciate its certainty. For the existence of my body issubject to doubts that the existence of my thinking resist. Indeed,the very attempt at thinking away my thinking is self-stultifying. The cogito raises numerous philosophical questions and hasgenerated an enormous literature. In summary fashion, I'll try toclarify a few central points. First, a first-person formulation is essential to the certainty of thecogito. Third-person claims, such as “Icarusthinks,” or “Descartes thinks,” are not unshakablycertain—not for me, at any rate; only the occurrence ofmy thought has a chance of resisting hyperbolic doubt. Thereare a number of passages in which Descartes refers to a third-personversion of the cogito. But none of these occurs in thecontext of trying to establish categorically the existence of aparticular thinker (as opposed merely to the conditional existence ofwhatever thinks). Second, a present tense formulation is essential to the certainty ofthe cogito. It's no good to reason that “I existedsince I recall I was thinking,” because methodic doubt callsinto question whether I'm having veridical memories. (Maybe I'm merelydreaming that I was thinking, or maybe an evil genius is feeding mefalse memories.) Nor does it work to reason that “I shallcontinue to exist since I am now thinking.” As the meditatorremarks, “it could be that were I totally to cease fromthinking, I should totally cease to exist” (Med. 2, AT7:27). The privileged certainty of the cogito is grounded inthe “manifest contradiction” (cf. AT 7:36) of thinkingaway my occurrent thinking. Third, the certainty of the cogito depends on beingformulated in terms of my cogitatio—i.e., my thinking,or awareness/consciousness more generally. Any mode of my thinking issufficient: doubt, understanding, affirmation, denial, volition,imagination, sensation, or the like (cf. Med. 2, AT 7:28). Mynon-thinking activities, on the other hand, are insufficient. Forinstance, it's no good to reason that “I exist since I amwalking,” because methodic doubt calls into question theexistence of my legs. (Maybe I'm just dreaming that I have legs.) Asimple revision, such as “I exist since it seems I'mwalking,” restores the anti-sceptical potency (cf. Replies 5, AT7:352; Prin. 1:9). A caveat is in order. That Descartes rejects the certainty offormulations presupposing the existence of a body commits him tonothing more than an epistemological distinction between mind andbody, but not yet an ontological distinction (as in substancedualism). Indeed, in the passage following the cogito,Descartes has his meditator say: And yet may it not perhaps be the case that these very things which Iam supposing to be nothing [e.g., “that structure of limbs whichis called a human body”], because they are unknown to me, are inreality identical with the “I” of which I am aware? I donot know, and for the moment I shall not argue the point, since I canmake judgements only about things which are known to me. (Med. 2, AT7:27) Fourth, and related to the foregoing quotation, is that Descartes'reference to an “I”, in the “I think”, is notintended to presuppose the existence of a substantialself. Indeed, in the very next sentence following the initialstatement of the cogito, the meditator says: “But I donot yet have a sufficient understanding of what this ‘I’is, that now necessarily exists” (Med. 2, AT 7:25). Thecogito purports to yield certainty that I exist insofaras I am a thinking thing, whatever that turns out tobe. The ensuing discussion is intended to help arrive at anunderstanding of the ontological nature of the thinking subject. More generally, one should keep distinct issues of epistemic andontological dependence. In the final analysis, Descartes thinks heshows that the occurrence of my thought depends (ontologically) on theexistence of a substantial self—to wit, on the existence of aninfinite substance, namely God (cf. Med. 3, AT 7:48ff). But Descartesdenies that an acceptance of these ontological matters isepistemically prior to the cogito: its privileged certaintyis not supposed to depend (epistemically) on abstruse metaphysics. Granting that the cogito does not presuppose a substantialself, what then is the epistemic basis for injecting the“I” into the “I think”? Many critics havecomplained that, in referring to the “I”, Descartes begsthe question—that he presupposes what is supposedly establishedin the “I exist.” Among the critics, Bertrand Russellobjects that “the word ‘I’ is reallyillegitimate”; that Descartes should have, instead, stated“his ultimate premiss in the form ‘there arethoughts’.” Russell adds that “the word‘I’ is grammatically convenient, but does not describe adatum.” (1945, 567) Accordingly, “there is pain” and“I am in pain” have different contents, and Descartes isentitled only to the former. One effort at reply has it that introspection reveals more than whatRussell allows—it reveals the subjective character ofexperience. On this view, there is more to the phenomenal story ofbeing in pain than is expressed by saying that there ispain: in the former case, there is pain plus apoint-of-view—a phenomenal surplus that's difficult tocharacterize except by adding that “I” am in pain, thatthe pain is mine. Importantly, my awareness of thissubjective feature of experience does not depend on an awareness ofthe metaphysical nature of a thinking subject. If we take Descartes tobe using ‘I’ to signify this subjective character, then heis not smuggling in something that's not already there: the“I”-ness of consciousness turns out to be (contra Russell)a primary datum of experience. And though, as Hume persuasivelyargues, introspection reveals no sense impressions suited tothe role of a thinking subject, Descartes, unlike Hume, feels nopressure to reduce all of our concepts to sense impressions.Descartes' idea of the self does ultimately draw on innateconceptual resources. Fifth, much of the debate over whether the cogito involvesinference, or is instead a simple intuition (roughly, self-evident),is preempted by three observations. One observation concerns theabsence of an express ‘ergo’(‘therefore’) inthe Second Meditation account. It seems amistake to emphasize this absence, as if suggesting that Descartesdenies any role for inference. For the Second Meditation passage isthe one place (of his various published treatments ) where Descartesexplicitly details a line of inferential reflection leading up to theconclusion that I am, I exist. His other treatmentsmerely say the ‘therefore'; the Meditationstreatment unpacks it. A second observation is that it seems a mistaketo assume that the cogito must either involve inference, orintuition, but not both. There is no inconsistency in the view thatthe meditator comes to appreciate the persuasive force of thecogito by means of inferential reflection, while also holdingthat his eventual conviction is not grounded in inference. A thirdobservation is that what one intuits might well include aninference: it is widely held among philosophers today that modusponens is self-evident, and yet it contains an inference. Thereis no inconsistency in claiming a self-evident grasp of a propositionwith inferential structure—a fact applicable to thecogito. As Descartes writes: When someone says “I am thinking, therefore I am, or Iexist,” he does not deduce existence from thought by means of asyllogism, but recognizes it as something self-evident by a simpleintuition of the mind. (Replies 2, AT 7:140)4.2 But is it Knowledge? There are interpretive disputes about whether the cogito issupposed to count as indefeasible Knowledge. (That is, about whetherit thus counts upon its initial introduction, prior to the argumentsfor a non-deceiving God.) Many commentators hold that it is supposedto count as indefeasible Knowledge. But the case for thisinterpretation is by no means clear. There is no disputing that Descartes characterizes the cogitoas the “first item of knowledge [cognitione]”(Med. 3, AT 7:35); as the first “piece of knowledge[cognitio]” (Prin. 1:194, AT 8a:7).Noteworthy, however, is the Latin terminology(‘cognitio’ and its cognates) that Descartes usesin these characterizations. As discussed in Section 1.3, Descartes is a contextualist in the sense that he uses ‘knowledge’ language in twodifferent contexts of clear and distinct judgments: the less rigorouscontext includes defeasible judgments, as in the case of the atheistgeometer (who can't block hyperbolic doubt); the more rigorous contextrequires indefeasible judgments, as with the brand of Knowledge soughtafter in the Meditations. Worthy of attention is that Descartes characterizes thecogito using the same cognitive language that he uses tocharacterize the atheist's defeasible cognition. Recall that Descarteswrites of the atheist's clear and distinct grasp of geometry: “Imaintain that this awareness [cognitionem] of his is not trueknowledge [scientiam]” (Replies 2, AT 7:141). Thisalone does not prove that the cogito is supposed to bedefeasible. It does, however, prove that calling it the “firstitem of knowledge” doesn't entail that Descartes intends it asindefeasible Knowledge. Bearing further on whether the cogito counts as indefeasibleKnowledge—available even to the atheist—is the NoAtheistic Knowledge Thesis (cf. Section 1.3 above). Descartes makes repeated and unequivocal statements implyingthis thesis. Consider the following texts, each arising in a contextof clarifying the requirements of indefeasible Knowledge (all italicsare mine): For if I do not know this [i.e., whether God is a deceiver], it seemsthat I can never be completely certain about anythingelse. (Med. 3, AT 7:36, trans. altered) I see that the certainty of all other things depends on this[knowledge of God], so that without it nothing can ever beperfectly known [perfecte sciri]. (Med. 5, AT 7:href="http://www.regional.topsites2007.com/">Regional -
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