Descartes and Dream Skepticism Revisited

Descartes and Dream Skepticism Revisited

Hanna, Robert, 1957-

Journal of the History of Philosophy, Volume 30, Number 3, July 1992,pp. 377-398 (Article)

Published by The Johns Hopkins University PressDOI: 10.1353/hph.1992.0050

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Descartes and Dream Skepticism Revisited

R O B E R T H A N N A

1 .

HERE tS A PUZZLZ abou t Descartes 's Meditations. In the first Meditation Descartes is able to infect h imself , as it were, with a p r o f o u n d skeptical difficulty abou t pe rcep tua l knowledge : what he calls " the principal reason for doubt , namely my inability to dis t inguish be tween be ing asleep and being awake.", But then in the sixth Meditation Descartes is p r e p a r e d to solve and dismiss this very same difficulty in a m e r e p a r a g r a p h ; h e r e we are told that " the exagge ra t ed doub t s o f the last few days should be dismissed as laughable" (CSM: I I, 61; AT: VII , 89). Was the skeptical worry a m e r e ma/ad/e imaginaire? Few phi losophers have been p r e p a r e d to laugh a long with Descartes.

It has in fact b e c o m e a phi losophical c o m m o n p l a c e that Descartes 's home- spun cure for his self-inflicted a i lment , his own a r g u m e n t against d r e a m skepticism, fails miserably. Hobbes , for instance, in the T h i r d Set o f Object ions to the Meditationa, suppl ies with ease what has general ly been r e g a r d e d as a knockdown c o u n t e r e x a m p l e to Descar tes 's antiskeptical a r g u m e n t (CSM: 1I, 137; AT: V l I , 195-96) . Descartes 's a p p a r e n t fai lure to answer his own skeptical p rob lem natura l ly leaves pos t -Car tes ian phi losophers with the old, old difficulty first m e n t i o n e d in the Theaetetm: "You see, then, that there is plenty o f r o o m for doubt , when we even d o u b t whe the r we are asleep or awake.""

Rent De~."-,rtes, Meditations on First PhilosoplU, in The Philosophical Wriling~ of Descartes, 3 vols., trans. J. Cottngham, R. Stoothoff, and D. Murdoch (Cambridge : Cambridge University Press, 1984--91 ), vol. II, p. 6 t; Oeuvres de Descartes, ed. C. Adam and P. Tannery (Paris: L. C, erf, 19o4), vol. VII, p. 89. All further references to Descartes's philosophical writings within the text of this essay will give volume and page numbers from these two editions, signified by the abbrevia- tions 'CSM' and 'AT' respectively.

' See Plato's Thraetetm, 158c-d. Plato's use of dream skepticism in the Theaetetus involves interesting similarities to, and differences from, Descartes's use of it in the first Meditation. For Descartes, the dream skeptic is attempting to cast doubt on the commonsensical epistemological principle that at least sometimes, and perhaps most of the time, the senses can give us secure

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T h a t is: I f I c a n n o t tell the d i f f e r e n c e be tween wak ing a n d d r e a m i n g with certainty, t h e n cou ld no t m y a p p a r e n t l y mos t secure o r ev iden t p e r c e p t u a l j u d g m e n t s t u r n o u t to be false?

T o be sure , u n t o l d n u m b e r s o f p h i l o s o p h e r s - - i n c l u d i n g K a n t a n d G. E. Moore m o s t f a m o u s l y s - - h a v e t aken a c rack at solving the d r eam-skep t i ca l p rob lem. Yet it is by no m e a n s an e x a g g e r a t i o n to say tha t these ant iskept ics have had at bes t an i n d i f f e r e n t success: ph i losoph ica l c o n s e n s u s cer ta in ly sug- gests tha t t he s t a n d a r d a r g u m e n t s agains t d r e a m skepticism4 are no m o r e successful t h a n Descar tes ' s own. T o m o d i f y Kan t ' s f a m o u s e p i g r a m a b o u t ex te rna l -wor ld skepticism,s the c o n t i n u i n g fa i lure to p r o v i d e an a d e q u a t e a r g u m e n t aga ins t d r e a m skept ic ism const i tu tes a ph i losoph ica l scandal .

I n my o p i n i o n , this lack o f success s tems at least in p a r t f r o m a fa i lure to u n d e r s t a n d a n d to l ea rn p r o p e r l y f r o m Descar tes ' s own a r g u m e n t s t ra tegy. Despi te its a i r o f f l ippancy, the single p a r a g r a p h in which Descar tes d i rec t ly attacks d r e a m skept ic ism involves a r a t h e r sophis t ica ted a r g u m e n t - - a n a r g u - m e n t far m o r e e f fec t ive a n d plausible t h a n is usual ly r e c o g n i z e d by in t e rp re t - ers and critics o f the Meditations. Consequen t ly , this a r g u m e n t calls o u t fo r m o r e ser ious ph i lo soph ica l scrut iny.

I n wha t fol lows in this p a p e r , I wan t to take a close look at Descar tes ' s actual m e t h o d o f a t tack on d r e a m skepticism. We shall d i scover tha t he is no t in fact even trying to p r o v e wha t mos t o f his critics accuse h i m o f fa i l ing to prove; n o r is he t ry ing to p r o v e it in the way m o s t o f his i n t e rp r e t e r s have supposed . Descar tes ' s ant iskept ica l s t ra tegy in the last p a r a g r a p h o f the sixth

knowledge via perceptual judgments (CSM: II, :a; AT: 18). So Descartes is attacking the epistemological credentials of perceptual judgment, and by implication, the epistemological framework of common sense. (Later in the Meditations, of course, these credentials and this framework are partially reinstated, although with special qualifications.) Plato on the other hand offers the dream problem strictly as a reductio of a particular theory of knowledge--namely, that proposed by Protagoras. There is no suggestion in the context of the dialogue that dream skepticism general- izes to perceptual judgment itself or to commonsensical epistemological principles. So Descartes's employment of the dream argument is far more radical than Plato's.

s Kant attempts the solution of the dream problem in the "Analogies of Experience"; see the Critique of Pure Reason, trans. N. K. Smith (New York: St. Martin's Press, 1957), aa7; A2ol-2O~/ B246-47. This must be kept conceptually distinct from his proof for the existence of the external world against the external-world skeptic in the "Refutation of Idealism"; see the Critique of Pure Reason, ~44-47; B274-79- Moore tries to answer the dream problem in "Certainty" in Philosophi- col Papers (London: George Allen and Unwin, 1959), 945-51 ; this must also be kept conceptually apart both from his attack on metaphysical idealism in "The Refutation of Idealism" in Philosophi- cal Studies (London: Routledge and Kegan Paul, 19a2), : -3 o, and from his proof for the existence of the external world in "Proof of an External World," in Philosophical Papers, 1 ~7-5 o.

4 An apparent implication of the philosophical consensus is that there is at bottom one and only one type of dream skepticism, even within Descartes's own writings. I reject this implication. Very shortly I will distinguish carefully between four Cartesian versions of dream skepticism, and isolate the version most impervious to antiskeptical arguments. See section 2.

s Kant, Critique of Pure Reason, 34; Bxxxix.

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Meditation is in fact quite carefully crafted and resistant to many of the standard critical assaults on it. This is not to say that in the end I wholeheartedly endorse Descartes's strategy. I do not; but I do want to maintain that its main thrust is more promising than has been previously thought, and that it may point us in the direction of a sound argument against dream skepticism.

9

Descartes's admirable lucidity virtually ensures that readers of the Meditations will realize immediately that any serious epistemologist must find a response to the following problem: Because we can apparently never tell the difference between waking experiences and dreaming experiences with complete certainty, it follows that our best-supported perceptual judgments (not to men- tion the weakly supported ones) could be false. 6 In order to feel the force of this problem, it is by no means necessary to infer as a consequence of the inability to distinguish between waking and dreaming with certainty, that all o f our perceptual judgments could or even must be false at oncemwe need only infer that each of our perceptual judgments could be challenged one at a time. The argument generating this latter inference is what I will call "epistemological dream skepticism.'7 (A more precise formulation of epistemological dream skepticism will be given shortly.)

What makes this fairly modest hypothesis so troubling to the epistemologist is precisely its modesty. The doubts motivated by it are so ord/nao: so commonsensical, and therefore so closely related to the average difficulties that arise in everyday contexts o f judgment and statement assessment. Epistemologi- cal dream skepticism implicitly challenges every single perceptual judgment , yet involves no obviously "wild" hypothetical conditions or entities. It trades exclusively on the commonsensical distinction between waking and dreaming,

6 Margaret Wilson in her Descartes (London: Roufledge and Kegan Paul, 1978), a3, argues that Descartes's aim in the dream argument is not to raise a doubt about whether one can tell the difference between waking and dreaming with certainty, but rather to raise a doubt about the veridicality of waking experience of physical objects. I f we have no reason to think that waking experience is veridical (because it differs in no discriminable way from dreaming experience and dreaming is nonveridical) then I could in any particular experience be mistaken about being awake, and my perception could be nonveridical. On Wilson's reading, in the sixth Meditation Descartes is then seeking to provide an argument for the veridicality of waking experience, not a criterion for telling waking from dreaming with certainty. That this is really Descartes's a rgument strategy seems unlikely for the simple reason that there are quite obviously nonveridical waking experiences such as being drunk or being very drowsy (while not actually being asleep), and it is only charitable to Descartes to credit him with having noticed this. See section 4-

7 I borrow this term from Harry Frankfurt 's Demons, Dreamers, and Madmen: The Defense of Reason in Descartes' Meditations (Indianapolis: Bobbs-Merrill, 197o), 7 ~. Frankfurt correcdy sees that this form of dream skepticism must be distinguished from other forms of dream skepticism that are more metaphysically loaded and immodest.

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t o g e t h e r wi th t h e p l a i n fac t t h a t we c a n m a k e j u d g m e n t s in o u r d r e a m s , ' a n d the f u r t h e r c o m m o n s e n s i c a l fac t t ha t t h e two m o d e s o f e x l ~ r i e n c o - - w a k i n g a n d d r e a m i n g - - c a n n o t b e d i s t i n g u i s h e d in p a r t i c u l a r cases wi th e p i s t e m i c ne - cessity. T h e w o m a n o n t h e s t r e e t sees s o m e t h i n g e x t r e m e l y u n u s u a l o r a p p a r - end) , i n c o h e r e n t a n d says s e r ious ly (as o p p o s e d to j o k i n g l y o r m e r e l y e x p l e - tivel) ') to h e r s e l f : " A m I n o w d r e a m i n g ? " H e r l i fe in all l i k e l i h o o d goes o n as usua l , b u t t h e m o m e n t o f d o u b t is ep i s t emolog ica l l ) , dec i s ive . '~ I n a w o r d , t h e d o u b t e n g e n d e r e d by e p i s t e m o l o g i c a l d r e a m s k e p t i c i s m is s t r ic t ly a p l a u s i b l e e x t e n s i o n o f w h a t T h o m p s o n C l a r k e calls " p l a i n d o u b t s " " - - a n d t ha t is w h y it is so ep i s t emica l l ) ' i n s i d ious .

A t this p o i n t it is c r u c i a l to d i s t i n g u i s h b e t w e e n s e v e r a l c lose ly r e l a t e d b u t d i s t inc t f o r m s o f C a r t e s i a n d r e a m skep t i c i sm. T h e f i n e - g r a i n e d d i s t i n c t i o n s a r c n e e d e d h e r e in o r d e r to a v o i d t r a d i t i o n a l c o n f u s i o n s in a n t i s k e p t i c a l a r g u - m e n t s t r a t eg i e s , n o t to m e n t i o n cr i t ica l a r g u m e n t s l e v e l l e d a t D e s c a r t e s ' s o w n a n t i s k e p t i c a l a r g u m e n t s . I t is i n t e r e s t i n g a n d even i m p o r t a n t t ha t o f all t h e r e a m s o f p a p e r f i l led wi th p r o - a n d a n t i s k c p t i c a l a r g u m e n t s , r e l a t i ve ly l i t t le space has b e e n d e v o t e d to g e t t i n g c l ea r o n j u s t e x a c t l y w h a t t h e C a r t e s i a n d r e a m skep t i c is p r o p o s i n g . " N e v e r t h e l e s s , a l i t t le t h o u g h t will s o o n c o n v i n c e

s Norman Malcolm in "Dreaming and Skepticism," Phi/osophical R*'m~ 65 (1956): 14-57, wants to deny that we can even make judgments or have propositional thoughts while asleep---- hence it will be incoherent to hold that judgments made during dreams might be false (or true). To set up as a necessary condition for all propositional attitudes that they be waking seems to confuse statements--which are public speech-acts governed by conventional succem-conditions-- with judg, ments. Judgments are not necessarily bound up with public speech-acts, since they can consist in silent or "inner" believings and hence may occur in dreams. Only statements, as public acts, seem to require that we be awake in order to make them.

9 Daniel Dennett, in "Are Dreams Experiences?" Philosophical Review 85 (1976): 151--71, argues that dreams are not even experiences--hence it is category mistake in the Rylean sense to compare them with waking experiences. Phenomenologically this seems wrong, quite independently of empirical evidence about the brain-states in waking and dreaming: to have an experience is to have some mental contents "before the mind" in a state of self-awareness, and this phenomenological criterion is satisfied in waking and dreaming alike.

,o It has sometimes been claimed that the question "Am I now dreaming?" is literally senseless, and hence cannot support a skeptical doubt. See, for example, R. Surer, "The Dream Argument," American Philosophical Quarterly 13 (July 1976): 191--94. To be sure, there is something pragmati- cally self-undermining about raising this question, when a presupposition of any acceptable answer to it is that one be in a position to answer it, and hence awake. But the pragmatics of question-raising apart, it is certainly logically possible that I could now be dreaming, and every proposition that is logically possible can have an interrogative operator prefixed to it. So there is nothing in logic or even semantics which prevents a sufficiently serious-minded individual from raising a perfectly intelligible question that she herself will not be in a position to answer if it is answerable in the affirmative.

"Thompson Clarke, "The Legacy of Skepticism," Journal of Plulosophy 69 ( 197 ~): 754-69 �9 '" A good example of the failure to distinguish carefully between the different types of

Cartesian dream skepticism, with resultant confusion as to precisely what is being argued for or against, is D. Blumenfeld and J. B. Blumenfeld, "Can I Know That I Am Not Dreaming?" in

D E S C A R T E S AND DREAM S K E P T I C I S M 3 8 I

us that there are at least four different versions of Cartesian dream skepticism, differing rather widely in strength and plausibility. In the present context, the "strength" of a skeptical argument will be said to increase in direct proportion to the stringency of its quantificational and modal implications, while its "plausibility" will be said to increase in inverse proportion to the same stringency of its implications.

Each of the skeptical arguments can be found, at least implicitly, in one or more Cartesian texts. The differing versions can be usefully distinguished, first, by giving the textual evidence, and then secondly, by formulating an argument based on that textual evidence (together with contextual evidence). The four varieties of dream skepticism will be listed and sketched immediately below, running from weakest (and hence most plausible) to strongest (and hence least plausible).

A. EpistemologicM Dream Skepticism. The famous and canonical formulation of epistemological dream skepticism, found in the first Meditation, runs as follows: "How often, asleep at night, am I convinced of just such familiar events--that I am here in my dressing-gown, sitting by the f i re--when in fact I am lying undressed in bed! . . . As if I did not remember other occasions when I have been tricked by exactly similar thoughts when asleep! As I think about this more carefully, I see plainly that there are never any sure signs by means of which being awake can be distinguished from being asleep" (CSM: II, 13; AT: VII, 19). And the further skeptical consequence as regards perceptual judgments is added in the following passage from the sixth Meditation: "Every sensory experience I have ever thought I was having while awake I can also think of myself as sometimes having while asleep; and since I do not believe that what I seem to perceive in sleep comes from things located outside me, I did not see why I should be any more inclined to believe this of what I think I perceive while awake" (CSM: II, 53; AT: VII, 77).

Here is my reformulation of this argument:

(l) There exists an external world. (Implicit premise) (2) There is a difference between my waking and my dreaming. That is: I do sometimes have waking experiences and do sometimes have dreaming experiences. (3) Yet sometimes these waking and dreaming experiences present themselves as identical, so that I cannot distinguish between them. (4) So there is never an effective criterion for telling whether a given experience is a waking one or a dreamt one.

Descartes: Critical and Interpretative Essays, ed. M. Hooker (Baltimore: John Hopkins Univ. Press, 1978), a34-55.

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(5) Since there is never an effective criterion for telling whether a given experience is waking or dreamt, then for each of my perceptual judgments which seems to describe the external world correcdy, I could at that moment be dreaming and the external world could be other than I describe it to be. (6) Thus each one of my perceptual judgments (at any given moment, independently of all my other perceptualjudgmentsps might be false, and I could be deceived about it.

It should be recognized that at this point I am claiming only that this reconstruction brings out the rational nub of Descartes's most plausible dream- skeptical argument; I am not also claiming that it is a sound argument. In fact, Descartes's own response to the argument, if correct, will show that the epistemological dream skeptic is arguing unsoundly-- in particular, that there is an invalid inference step from (8) to (4). But more on that below. I want now, briefly, to compare epistemological dream skepticism with three other versions of dream skepticism with which it is often confused.

B. UniversalDream Skepticism. It can easily be seen from step (6) of epistemological dream skepticism that the doubt is somewhat modestly restricted to one perceptual judgment at a time, although it implicitly ranges over all the judgments. But this fairly weak conclusion naturally points up by contrast a much stronger one: that all perceptual judgments might be false at once. Descartes sets up the argument to this stronger conclusion in the following passage from the Discourse on the Method: "Considering that the very thoughts we have while awake may also occur while we sleep without any of them being at that time true, I resolved to pretend that all the things that had ever entered my mind were no more true than the illusions of dreams" (CSM: I, 197; AT: VI, 3~). An equivalent formulation of this argument can be found in The Search after Truth: "How can you be sure that your life is not a continuous dream, and that everything you think you learn through your senses is not false now, just as much as when you are asleep?" (CSM: II, 408; AT: X, 511-12).

And here is my reconstruction of this skeptical gambit:

(i) There exists an external world. (Implicit premise) (2) For every experience I have that appears to be waking, there can be a dreaming experience that is identical to it. (3) So my whole life might be a dream.

lsAs Peter Markie correctly notes, the first dream argument in the first Meditation is best construed as leading to the conclusion that Descartes may now be dreaming. In this way the skeptical doubt is restricted to the occasion of framing any particular perceptual judgment . See Descartes's Gambit (Ithaca: Cornell University Press, 1986), I 19, 12 I.

D E S C A R T E S AND DREAM S K E P T I C I S M 383 (4) If my whole life might be a dream, then all of my perceptual judgments might refer falsely to the external world. (5) Thus the entire set of my perceptual judgments might be false, and I could be deceived about them all.

The difference between the relatively weak conclusion of epistemological dream skepticism and the stronger conclusion of universal dream skepticism should be obvious. As Bernard Williams aptly puts it, there is a crucial logical difference between "the universal possibility of illusion" and the "possibility of universal illusion."'4

C. Ontological Dream Skepticism. Now we move on to headier skeptical stuff, by availing ourselves of an appeal to an omnipotent God. Descartes writes in the first Meditation: "How do I know that [an omnipotent God] has not brought it about that there is no earth, no sky, n o extended thing, no shape, no size, no place, while at the same time ensuring that all these things appear to me to exist just as they do now?" (CSM: II, 14; AT: VII, 21). And this fits nicely with a skeptical worry expressed earlier in the first Meditation, but which seems rather out of place in either epistemological or universal dream skepticism: "Suppose then that I am dreaming, and that these particulars--that my eyes are open, that I am moving my head and stretching my hands- -are not true. Perhaps, indeed, I do not even have such hands or such body at all" (CSM: II, 13; AT: VII, 19).

Taking these two passages together, we can formulate the following argument:

(1) An omnipotent God can bring it about that the external world does not exist. (Implicit premise) (2) If an omnipotent God can bring it about that the external world does not exist, but I still continue to think I am experiencing the external world, then that God might have created my whole life as a dream. (3) If the external world might not exist according to God's decree, and if my whole life might be a dream, then all of my perceptual judgments apparently referring to the external world might be false and I could necessarily be deceived about them all. (4) Thus the entire set of my perceptual judgments might be false and I could necessarily be deceived about them all.

Under ontological dream skepticism it is not only the case that all of my perceptual judgments might be in fact false: they might be false in such a way that I have to be deceived about them. The necessity stems primarily from the

~4 Bernard Williams, Descartes: The Project of Pure Enquiry (Adantic Highlands, N J: Humanities Press, i978), 54-

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fact that under the skeptical hypothesis not only am I continually dreaming, so that my judgments are all nonveridical, but also the external world fails to exist by God's decree, so necessarily none of the referring terms in my judgments has a referent. In a word, all my judgments contain as referring terms only vacuous names, so in principle none of my judgments can be true. As a skeptical predicament this is bad enough; but things could get still worse for the Cartesian dreamer.

D. Evil Demon Dream Skepticism. We now move on to the most lurid of all the dream-skeptical arguments. Here is how Descartes frames it in the first Medita- tion: "I will suppose therefore that not God, who is supremely good and the source of truth, but rather some malicious demon of the utmost power and cunning has employed all his energies in order to deceive me. I shall think that the sky, the air, the earth, colors, shapes, sounds and all external things are merely the delusions of dreams which he has devised to ensnare my judgment . I shall consider myself as not having hands, or eyes, or flesh, or blood, or senses, but as falsely believing that I have all these things" (CSM: II, x5; AT: VII, 22-~3).

And here is how this argument can be reconstructed:

(i) There may exist a very powerful being (not God) which uses all of its energies in order to deceive me. (~) Under this hypothesis, since I am being systematically deceived, and since I believe the external world to exist, the external world might necessarily not exist. (3) Also under this hypothesis, since I am being systematically deceived, my whole life might be a dream. (4) Since the external world might necessarily not exist, and since my whole life might be a dream, and since the systematic deception covers all my judgments, perceptual or nonperceptual, then the total set of my judgments might be false and I could necessarily be deceived about them. (5) So the total set of my judgments (of any type) might be false and I could necessarily be deceived about them.

Notice the important difference between ontological dream skepticism and evil demon dream skepticism. It is one thing to hypothesize that God might have created me (for some reason unknown to my finite intellect) in such a way that I was necessarily deceived about my perceptual j udgmen t s - -bu t not my mathematical judgments (CSM: II, i4; AT: VII, 2o)- -and quite another to hypothesize that a certain very powerful being (who was not God) was able and willing to go to such lengths to deceive me that not only all my perceptual judgments, but also my mathematical judgments, would come out false and I would have to be deceived about them.

D E S C A R T E S AND DREAM S K E P T I C I S M 3 8 5

Many subtle but telling differences between the various forms of skepticism could be noted. Most salient are the changes in (~) the ontological status of the external world, and (9) the quantity and modality of the propositions expressing the skeptical conclusions.'5 These changes naturally lead to important differences in the epistemological scope of each skeptical argument. One could easily go on at some length comparing and contrasting the different skeptical types, and exploring their various consequences. But for the present purposes I have something simpler in mind. The broad thesis I am putting forward here is that Descartes employs at least four distinct dream-skeptical arguments in his writings, by progressively strengthening dream-skeptical premises and conclusions. Nevertheless my particular task in this paper is only to examine Descartes's arguments against the weakest and most plausible form of skepticism, namely epistemological dream skepticism. For short I will henceforth call it simply "dream Skepticism"; the other forms of dream skepticism are understood to be excluded.

My justification for fixing on only the weakest variety of dream skepticism is twofold. First, as I have implied already, the most tenable and troublesome form of skepticism is bound to be the weakest one, in that its ontological, quantificational, and modal demands are least extravagant. Hence it will com- port most easily with ordinary intuitions about the world, knowledge, and about what it takes to raise a "plain doubt" about a given perceptual judgment . And secondly, there do seem to be sound counterarguments already available for use against the other three forms of dream skepticism. 16

'~ In epistemological dream skepticism we condude to the universal possibility of illusion for perceptual judgments; in universal dream skepticism we condude to the possibility of universal illusion for perceptual judgments; in ontological dream skepticism we conclude to the necessity of universal illusion for perceptual judgments; and finally in evil demon dream skepticism we conclude to the necessity of universal illusion for all judgments whatsoever.

,s Thompson Clarke's argument in "The Legacy of Skepticism," 766-68, seems to be telling against universal dream skepticism; Hilary Putnam's argument against "brain-in-the-vat" skepticism in Reason, Truth, and History (Cambridge: Cambridge University Press, 198 l), 1-21, appears to be effective against ontological dream skepticism; and the following rather old-fashioned self- refutation argument seems to be quite effective against evil demon skepticism. This argument is suggested by Descartes's toss-away remark that the only thing remaining true under the evil demon, hypothesis is "perhaps just the one fact that nothing is certain" (CSM: II, 16; AT: VII, 24). The obvious response to this remark is: Why should that fact escape the skeptical net? Isn't the skeptic being inconsistent then? The argument runs as follows:

(a) The evil demon skeptic believes that every belief could be false. (2) Now suppose that belief to be true. Then there is a possible set of circumstances in which every belief actually is false. (3) Since every belief is false in the possible set of circumstances under the supposition, then even the belief that possibly every belief is false, is false. (4) Therefore under the supposition that the belief is true, it turns out to be false. (5) So the evil demon skeptic's belief is self-contradictory and hence false, by reductio.

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3" T h u s I will now a s s u m e f o r the sake o f this in t e rp re t a t ion , a n d by the char i t ab le pr inciple tha t Desca r tes w o u l d u l t imate ly ( b e y o n d the va r ious dialectical m o v e s r ehea r sed in the ear ly s tages o f the medi ta t ive a r g u m e n t a t i o n ) t ry to a r g u e against on ly the m o s t p lausible a r g u m e n t c o n t r a r y to his o w n posi t ion, tha t his a r g u m e n t aga ins t d r e a m skept ic ism in the last p a r a g r a p h o f the sixth Meditation is i n t e n d e d to a t tack ep i s t emolog ica l d r e a m skept ic ism only , and no t o n e o f the less plausible variet ies o f d r e a m skept ic ism. This a s s u m p t i o n is in any case b o r n e ou t by Descar tes ' s o w n charac te r i za t ion o f the ve rs ion o f the d r e a m skepticism he in t ends to de f ea t in the last p a r a g r a p h o f t he Meditations. I will now quo te the r e l evan t p a r t o f this p a r a g r a p h in full, i n c l u d i n g Descar tes ' s ant iskeptical a r g u m e n t , b o t h because it s u p p o r t s m y last c la im a n d because it will p rove usefu l to h a v e it in f r o n t o f us f o r the fo l lowing discussion.

Accordingly, I should not have any fur ther fears about the falsity o f what my senses tell me every day; on the contrary, the exaggerated doubts o f the last few days should be dismissed as laughable. This applies especially to the principal reason for doubt, namely my inability to distinguish between being asleep and being awake. For I now notice that there is a vast difference between the two, in that dreams are never linked by memory with all the o ther actions o f life as waking experiences are. If, while I am awake, anyone suddenly were to appear to me and then disappear immediately, as happens in sleep, so that I could not see where he had come from or where he had gone to, it would not be unreasonable for me to judge that he was a ghost, or a vision created in my brain, ra ther than a real man. But when I distinctly see where things come from and where and when they come to me, and when I can connect my perceptions of them with the whole o f the rest of my life without a break, then I am quite certain that when I encounter these things I am not asleep but awake. And I ought not to have even the slightest doubt of their reality if, after calling upon the senses as well as my memory and my intellect in order to check them, I receive no conflicting reports from any of these sources. For f rom the fact that God is not a deceiver it follows that in cases like these I am completely free f rom error. (CSM: II, 6x-6u; AT: VII, 89 -90 )

T h u s Descar tes . I t is s t r ik ing tha t a lmos t every i n t e rp re t e r , and in pa r t i cu - lar a slightly myth ica l beas t I shall call the " s t a n d a r d i n t e r p r e t e r " o f this passage, '7 takes Descar tes to be a r g u i n g in r o u g h l y the fo l lowing way: ( l ) t ha t the re is a skeptical d i f f icu l ty a b o u t p e r c e p t u a l j u d g m e n t to the e f fec t t ha t because we c a n n o t tell d r e a m i n g f r o m wak ing expe r i ences with cer ta in ty , any

,7 The "standard interpreter" is of course an ideal type, although the type does represent the majority of the readers of this passage. Closest to the ideal type's profile is Hobbes (CSM: I1, 137; AT: VII, 195-96). More recent friends of the standard interpretation include (in the 195os ) Norman Malcolm in Dreaming (London: Routledge and Kegan Paul, 1959), 1o1--1o8; (in the t96os ) Anthony Kenny in his Descartes: A Study of His Philosophy (New York: Random House, 1968), 29-3o; (in the 197os ) Edwin Curley, Descartes against the skeptics (Cambridge: Cambridge University Press, 1978), 66-68; and (in the 198os ) Peter Markie in Descartes's Gambit, 124-~ 5.

D E S C A R T E S A N D D R E A M S K E P T I C I S M 387 putatively true perceptual j u d g m e n t could be really a d reamt experience and hence false; (2) that he, Descartes, can supply an infallible criterion such that for any experience whatsoever it will be possible to tell whether it is a waking experience or a d reaming experience; 's (3) that in virtue o f possessing this criterion the d ream skeptic is answered and thereby refuted. In addition, the s tandard reading o f this passage has it that an unjustified appeal to God's nondeceitfulness plays an essential and direct role in g round ing the infallible criterion. On the basis o f this interpretat ion, the s tandard in terpre ter is able to show very easily that Descartes's a rgumen t is fatally f l awed- - tha t the proposed criterion is a miserable failure. I want to insist that it is precisely the reading of the s tandard in terpre ter that is fatally flawed, and that because Descartes is not by any means a rgu ing in the manne r normally ascribed to him, his real a rgumen t has a much better chance of success.

Let me now formulate the s tandard interpretat ion more precisely. For the s tandard reader, the structure o f Descartes's a rgumen t is as follows. We begin by assuming that we do at least sometimes have waking experiences and at other times d reaming experiences. It is nevertheless difficult and perhaps impossible to tell with any certainty for any given case o f experience whether it is waking or dreamt , since there can be rather vivid dreams presenting themselves as waking experiences. So (the skeptic concludes) any particular case of a perceptual j u d g m e n t could in principle be dreamt, and hence false. But the Cartesian antiskeptic confidently replies that what characterizes all and only the cases of waking experience is the following: a certain connectability or continuity between past experiences as remembered and the present experience, and between the d i f ferent parts o f the total present experience. (Let us call this structure, for convenience, the "coherence structure.") When an experience seems to possess the coherence structure, it is a waking experience; when an experience seems to lack the coherence structure, it is a dreaming experience. This criterion, according to the s tandard interpreter , is guaran- teed for Descartes by clear and distinct intuition. There fo re we can always tell waking f rom dreaming experiences with certainty, and the perceptual judgments made in waking experiences are epistemologically secure. As Descartes puts it: "when I can connect my perceptions o f [things] with the whole o f my

,8 Some interpreters of greater subtlety, such as Bernard Williams, modify this step of the argument by restricting the infallible criterion's scope to waking ex,perience5 only. Thus the criterion would be effective strictly in picking out all and only waking experiences; it could quite possibly go awry in failing to recognize, for some very vivid dreaming experiences, that those experiences are in fact dreamt. See Williams's Descartes: The Project of Pure lnqu/~, 312-13. For all its subtlety, this construal is nevertheless implausible for the simple reason that there are some waking experiences that not only are, but also appear to be, less coherent than some dreams. See section 4 of this essay.

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life without a break, then I am quite certain that when I encounter these things I am not asleep but awake."

Now to be sure the s tandard reader , on this construal o f Descartes's argument, immediately spots an obvious difficulty. For it is very clear that in principle at least, d reams can seem every bit as well o rdered and well connected within the dream world, as waking experience is in the real world. As Hobbes puts it:

"My question is w h e t h e r . . , a man could not dream that his d r eam fits in with his ideas of a long series o f past events. I f this is possible, then what appear to the dreamer to be actions belonging to his past life could be j u d g e d to be t rue occurrences, jus t as if he were awake" (CSM: II, 137; AT: VII, 195 ). So Des- cartes's proposed criterion would seem to be insufficient: it is possible to have experiences apparently bearing the coherence structure of waking life, that are nevertheless d reaming experiences. At this point, again on the s tandard reading, Descartes moves to a fall-back strategy: our conviction that certain apparently coherent experiences are genuinely waking experiences (because o f their satisfaction o f the coherence criterion) is so strong and evidentially suppor ted that if we really were to be mistaken, then God would have to be a deceiver. For God underwrites the rule relat ing clear and distinct intuitions to the truth, and the coherence criterion is certified by clear and distinct intuition. But God is not a deceiver. So the criterion is infallible: " f rom the fact that God is not a deceiver it follows t h a t . . . I am completely free f rom error."

At this last stage in the s tandard reading of the argument , the interpreter- turned-critic throws up his hands in dismay: the appeal to God would seem to be a mere deus ex machina; it seems available to Descartes only because his otherwise weak a rgumen t is in trouble. Independent ly of the appeal to God, the proposed criterion is obviously insufficient. And there are in any case independent a rguments against Descartes's proofs for the existence of God.

.

What I want to do now is to re in terpre t Descartes's a rgument in such a way that the unsound a rgument so easily exploded by the standard in terpre ter is seen for what it is: a mere caricature o f Descartes's actual p roof strategy. The first very important thing to realize about Descartes's a rgument against d ream skepticism is that he is in fact not even arguing for the conclusion the s tandard reading takes him to be a rguing for. Close attention to the above-quoted passage will reveal that contrary to the normal interpretation, Descartes is not trying to argue for a universal infallible criterion for dist inguishing waking experiences f rom dreaming experiences. '9 According to the s tandard inter-

,9 Interestingly, Leibniz does seem to defend just such a universal, infallible criterion for telling waking and dreaming experiences apart; and his candidate for such a criterion is the

D E S C A R T E S A N D D R E A M S K E P T I C I S M 389

preter , Descartes opposes to the crucial premise o f d ream skept ic i sm-- tha t we cannot distinguish with certainty between waking and d r e a m i n g - - i t s logical contrary, namely, that we can always distinguish with cer tainty between waking and dreaming . But on my construal o f Descartes, he opposes to the crucial premise o f d ream skepticism not its logical cont rary but its logical contradictory, namely, that we can sometimes distinguish with cer tainty between waking and dreaming . Special note should be taken o f the italicized phrases in the following passages: "but when I distinctly see where things come f rom and where and when they come to me, and when I can connect my percept ions o f them with the whole o f the rest o f my life without a break, then I am quite certain that when I encoun te r these things I am not asleep but awake"'~ and " f rom the fact that God is not a deceiver it follows that in cases like these I am completely f ree f rom e r r o r " " (emphasis added) . Descartes's employmen t o f the coherence- s t ructure cri terion is in fact much mo re restricted than an ou t r igh t universal, infallible applicability to all exper iences; it applies only to a certain range o f cases that are constra ined by thei r meet ing a certain set o f special conditions.

Nor, secondly, does the s tandard reade r correct ly cons t rue the meaning o f the coherence-s t ruc ture cri terion. Descartes clearly recognizes a d i f ference between genuine coherence in exper ience and merely apparent coherence , while the s tandard reader runs them together . As Descartes puts it in his response to Hobbes: "A d r e a m e r cannot really connect his dreams with the ideas o f past events, though he may d r e a m he does. For everyone admits that a man may be deceived in his sleep" (CSM: II, 137; AT: VII, 196 ). T h e crucial word in this passage is 'really'. Descartes is he re making an implicit dist inct ion'between the ontology of waking and d reaming exper iences , and their epistemology. It is possible to make remarks about the na tu re o f waking and dreaming , drawing structural or conceptual distinctions between them, without having to claim that this ontological d i f fe rence is always epistemically recognized. T h e difference may only be sometimes recognized. We shall have mo re to say about this shortly. But for the m o m e n t we need only note that the s tandard reader errs not only by failing to draw this distinction, bu t also by unjustifiedly foisting this fa i lure on Descartes.

coherence-structure criterion. See New Essays on Human Understanding, trans. P. Remnant and J. Bennett (Cambridge: Cambridge University Press, 1981), 374-75. Berkeley defends essentially the same view in the third of the Three Dialogues between Hylas and Philonous; see Berkeley's Philosophi- cal Writings, ed. D. M. Armstrong (New York: Collier Macmillan, 1965), 197. It seems possible that much of the impetus for the standard interpretation of Descartes's anti-dream-skeptical argument comes from these sources.

'~ Latin and French originals of this passage can be found in note 28 below. '~ The Latin and French originals of this passage are as follows: "Ex eo enim qubd Deus non

sit fallax, sequitur omnino in talibus me non falli" (AT: VII, 9o); "Car de ce Dieu n'est point trompeur, il suit n~cessairement queje ne suis point en cela trompC' (AT: IX, 72).

39 ~ JOURNAL OF THE HISTORY OF PHILOSOPHY 3 0 " 3 JULY I 9 9 2

Here, then, is how Descartes actually employs the coherence-structure criterion. In order for there to be a general epistemological issue as between waking and dreaming experiences, we have assumed that there are at least some cases of waking, and some of dreaming. Every experience presents itself clearly before the mind in the minimal sense that it is recognized by the mind as experienced: "I am now seeing light, hearing a noise, feeling heat. But I am asleep, so all this is false. Yet I certainly seem to see, to hear, and to be warmed. This cannot be false" (CSM: II, 19; AT: VII, 29). Yet clarity alone does not automatically entail distinctness," so it is possible that there exist at least some actual cases of waking experiences that are structurally and epistemically indistinguishible from cases of dreaming. As J. L. Austin points out in Sense and Sensibilia, "we have the phrase 'a dream-like quality'; some waking experiences are said to have this dream-like quality.",s There are, as anyone who has risen from bed at 5:30 AM (or who has been drunk) will know, waking experiences of a highly blurry and epistemically ambiguous nature. Such experiences could well have been dreamt. Such experiences are at once (a) actually waking, (b) really incoherent, and also (c) apparently incoherent.

But this fact is consistent with there being clear cases of waking that are also distinct cases of waking-- that is, in addition to being immediately obvious, such experiences also embed some recognizable criterion of individuation. By contrast, then, these experiences will be (a) actually waking, (b) really coherent, and also (c) apparently coherent. So it is by no means necessary for Descartes to claim that all experiences which are in fact waking ones will either actually be, or present themselves as, coherent.

Nor is it necessary for Descartes that only waking experiences will present themselves as obviously or clearly waking experiences. Some dreaming experiences may present themselves as very similar to waking experiences; they may possess a high degree of apparent coherence, although they are not in fact actually coherent. This high degree of apparent coherence may well be sufficient, moreover, to fool us on occasion into thinking that such experiences are waking when they are in fact dreamt. As the architect of the dream-skeptical argument(s) in the first Meditation, Descartes can hardly be convicted of deny- ing that such pseudo-waking experiences are possible: "How often, asleep at night, am I convinced of just such familiar events--that I am here in my dressing gown, sitting by the f i re- -when in fact I am lying undressed in bed!" (CSM: II, 13; AT: VII, 19). Hence it is not necessary for Descartes to claim that only waking experiences bear the appearance of being continuous and

�9 "This is pointed out by Descartes in The Principles of Philosophy (CSM: I, 207; AT: VillA, 21--29).

,s Austin, Sense and Sensibilia, ed. G.J. Warnock (London: Oxford University Press, 1962), 49.


connectable. He is commit ted to the claim that only (but not necessarily all) waking experiences actually bear the coherence structure, but that is perfectly consistent with the claim that s o m e - - p e r h a p s very m a n y n d r e a m i n g experiences appear to be coherent.

So what Descartes is commit ted to arguing is as follows. Amongst the several waking experiences that there are, some of them may actually bear the coherence structure. Others may be relatively incoherent. For those that are coherent in fact, they are i'n addi t ion such that they cannot be taken to be d reaming experiences: they are, clearly and distinctly, recognized to be waking experiences.'4 (This claim of course amounts to a denial o f the crucial step (4) of the epistemological d ream skeptic's a r g u m e n t - - t h a t waking and dreaming can never be dist inguished with certainty. So, if true, this demonstrates the unsoundness of epistemological d r e a m skepticism.) Other experiences that are in fact d reamt may seem to be coherent , but not be; such experiences are ones that may fool us. But their appear ing to be coherent does not automatically make them coherent; only some apparent ly coherent experiences are actually coherent.

And for such experiences, which we assume actually to bear the coherence structure, they must necessarily present themselves as coherent. Other pseudo- waking experiences may also present themselves with similar degrees of apparent coherence. But it will never happen that an experience which is in fact coherent will in fact be presented as incoherent and dreamy. I f there were, then God would most certainly have to be a deceiver. But God is not a deceiver. So every actually coherent waking experience will present itself as coherent. There- fore there will be at least some experiences which are not only waking experiences but show themselves to possess a s t ructure that only waking experiences actually have. So the skeptic is wrong to claim that we can never distinguish with certainty between waking and dreaming. And thus the skeptic is also wrong to claim that there cannot be some secure perceptual judgments . For those judgments that occur in waking experiences which are actually coherent, are secure.

In this way Descartes is by no means a rguing for an infallible criterion for solving the decision problem with respect to waking/dreaming for evev'y experience. Nor is he arguing that apparen t coherence suffices for picking out only waking experiences. All he is a rguing for is the existence o f a criterion which is effective for some paradigm cases that are reliable with respect to that very decision problem. Some experiences are such that they do not present themselves as coherent unless they are coherent ; and all such experiences are wak-

�9 4 This amounts to a denial of a claim made by J. Stone in "Dreaming and Certainty," Philo- sophieal Studies 45 (1984): 353, to the effect that being awake is a "self-recognizing" state. Accord- ing to the present account, only some, but not all, waking experiences are self-recognizing.

392 JOURNAL OF THE HISTORY OF PHILOSOPHY ~O: 3 JULY t 9 9 2

ing experiences. In my opinion this is a far more defensible argument than the one foisted on Descartes by the standard reading. In particular, it is not affected by the claim, conceded by Descartes right from the start, that some dreaming experiences seem very coherent and can fool us. He is only insisting on the other hand that some experiences which seem very coherent are in fact coherent and therefore do not fool us because: (1) every actually coherent experience is necessarily a waking one; and (2) some waking experiences (i.e., the ones that are actually coherent) never present themselves as incoherent because they contain a clear and distinct intuition of the causal sources of the contents of the experience--otherwise God would be a deceiver.

To be sure, each of these supporting reasons needs to be argued for. All I want to insist at the moment is that neither reason is obviously implausible, nor is either reason subject to the standard critical knockdown counter- example to the standard reading of the dream-skeptical argument (namely, that there are some highly convincing dreams).

.

Let me now present Cartesian arguments for the two reasons. First, as regards the claim that "every actually coherent experience is necessarily a waking one" one need only carefully interpret Descartes's remark that "I now notice that there is a vast difference between the two [i.e., between being asleep and being awake], in that dreams are never linked by memory with all the other actions of life as waking experiences are." Notice immediately that Descartes is not saying here that dreams can never seem to be "linked by memory with all the other actions of life as waking experiences are"-- that is, can never seem to be coherent. He is simply saying that by their very nature dreams can never actually be coherent; they can quite possibly seem to be coherent. Nor is Des- cartes saying that all waking experiences are actually coherent; he is simply saying that dreams never bear the coherence structure that only (not necessarily all) waking experiences bear. I f it is necessarily the case that all dreams are incoherent experiences, then it is a direct consequence (by contraposition) that it is necessarily the case that all nonincoherent experiences are nondreams; that is: all coherent experiences must be waking experiences.

On my reading, then, Descartes's claim here is the expression of an analytic truth about the ontology of dreams. Dreams are, by their very nature, necessarily not possessed of the coherence structure. I f dreams were actually coherent, then of course they would not be dreams but rather waking experiences. As Austin points out, again in Sense and Sensibilia: "I f dreams were not 'qualita- tively' different from waking experiences, then evoy waking experience would be like a dream; the dream-like quality would be, not difficult to capture, but

D E S C A R T E S A N D D R E A M S K E P T I C I S M 3 9 3

i m p o s s i b l e to avoid ." ,5 T h u s w h a t D e s c a r t e s d o e s h e r e is s i m p l y to m a k e a n o b s e r v a t i o n v e r y l ike " p i n k is n o t a p r i m a r y c o l o r " o r "2. 5 is n o t a w h o l e n u m b e r . " D r e a m s j u s t are e x p e r i e n c e s " n e v e r l i n k e d by m e m o r y wi th all t h e o t h e r ac t ions o f l i fe as w a k i n g e x p e r i e n c e s a r e " - - t h i s is j u s t p a r t o f t he c o n t e n t o f t h e ve ry c o n c e p t o f a d r e a m .

So D e s c a r t e s ' s r e m a r k a b o u t t h e c l e a r a n d d i s t i nc t d i f f e r e n c e b e t w e e n waking a n d d r e a m i n g is m e r e l y a bi t o f c o n c e p t u a l ana lys i s a b o u t " w h a t t h e r e is," a n d a qu i t e p l a u s i b l e bi t at tha t . A l t h o u g h it is o b v i o u s t ha t a g iven d r e a m m a y seem to a g iven d r e a m e r to be c o h e r e n t , it s e e m s to be c o n s t i t u t i v e o f d r e a m - ing t ha t t h e r e a r e g a p s a n d d i s c o n t i n u i t i e s in t h e d r e a m w o r l d , en t i t i e s w i th in t he d r e a m w o r l d f o r w h i c h L e i b n i z i a n laws o f i d e n t i t y d o n o t h o l d , p r o p o s i - t ions a b o u t t ha t d r e a m w o r l d w h i c h have n o t r u t h - v a l u e , a n d n o ex i s t en t i a l c o m m i t m e n t to t h e c o n t e n t s o r " f u r n i t u r e " o f t h e d r e a m w o r l d . "6 As I have m e n t i o n e d a l r e a d y , we m u s t s e p a r a t e t he epistemological q u e s t i o n o f h o w we know o f a d r e a m tha t it is a d r e a m , f r o m t h e ontological q u e s t i o n o f t h e s t r u c t u r e o f d r e a m s . ' v I t is to be r e m e m b e r e d t ha t t he e p i s t e m o l o g i c a l d r e a m skep t i c g r a n t s f r o m the s t a r t t ha t b o t h w a k i n g a n d d r e a m i n g e x p e r i e n c e s exis t ; he t h e r e f o r e a lso impl i c i t ly a d m i t s t ha t w a k i n g a n d d r e a m i n g have dis- t inct s t r u c t u r e s m t h a t t hey a r e o n t o l o g i c a l l y d i s t i n c t t y p e s o f e x p e r i e n c e .

1 w a n t n o w to g o on to t he C a r t e s i a n d e f e n s e o f t h e s e c o n d r e a s o n f o r a n t i s k e p t i c i s m g i v e n above , n a m e l y , t ha t s o m e w a k i n g e x p e r i e n c e s (i.e., t he ones t ha t a r e a c t u a l l y c o h e r e n t ) n e v e r p r e s e n t t h e m s e l v e s as i n c o h e r e n t because they c o n t a i n a c l ea r a n d d i s t i n c t i n t u i t i o n o f t h e causa l s o u r c e s o f t h e e x p e r i e n c e - - o t h e r w i s e G o d w o u l d be a d e c e i v e r . My a r g u m e n t o n Desca r t e s ' s

�9 s Austin, Seine and Semibilia, 49- ,6 For example, suppose I am having a dream about a certain place--say, a university lecture

hall. Not every aspect of the hall as a spatio-temporal entity will be presented in the dream: there will be gaps in the dreamt space-time. Moreover, certain entities within the dreamt lecture hall (say, students' faces) will at once be distinct from one another, and then somehow become identical to one another. Also, certain propositions about the dreamt hall--say, 'There are exactly 15o chairs in this hall'--will be neither true nor false. And finally, a necessary feature of the dream is that the dreamt lecture hall does not actually exist (although I may, in the dream, believe that it exists, and although an actual lecture hall may share some perceptual properties with the dreamt one). For a detailed philosophical description of dreams very similar to the one just sketched, see J.-P. Sartre's brilliant but little-known work, The Psychology of the Imagination (Secaucus, N J: Citadel Press, n.d.), 231-55.

�9 ~ What accounts for the structural peculiarities of dreams? The closest Descartes comes to an account of the metaphysics of dreams can be found in a letter to Elizabeth of Bohemia: "Those [thoughts] that depend on the traces left by previous impressions in the memory and the ordinary motion of the spirits are d reams . . , the soul does not determine itself to anything of itself but idly follows the impressions in the brain." See Descartes: Philosophical Letters, trans, and ed. A. Kenny (Oxford: Clarendon Press, 197o), 178. The idea here seems to be that the structural "gappiness" of dreams directly supervenes on a loose organization of various brain-traces.

394 J O U R N A L OF T H E H I S T O R Y OF P H I L O S O P H Y 3 0 : 3 JULY 1992

behalf in favor o f this claim consists in an interpretat ion o f another normal ly misread text f rom the long passage I quoted above: "But when I distinctly see where things come f rom and where and when they come to me, and when I can connect my percept ions o f them with the whole rest o f my life without a break, then I am quite certain that when I encoun te r these things I am not asleep but awake ."" T h e first th ing to notice here is the careful condit ional qualification o f the a r g u m e n t to the desired conclusion: I can be certain that I am awake i f I can distinctly see where things come from, etc., and i f at the same time my exper ience is actually (not just apparent ly) coherent . In o ther words, apparen t s t ructural coherence , even when combined with actually waking experience, is not sufficient to guarantee the epistcmic certainty that a given experience is a waking one. Two o ther condit ions are required.

Waking experiences need two features in addit ion to their apparen t coherence in o rder to bc waking experiences recognized with certainlymin o r d e r for it to be the case that such experiences could never present themselves as incoherent (hence as possibly dreamt). The first and most obvious one is actual coherence. T h e second and less obvious one, which in fact entails actual coherence, is a clear and distinct recognition, within the experience, o f the causal sources of the contents o f the experience ("when I distinctly see where things come from and where and when they come to me",9 [emphasis added]). Wak- ing experiences recognized with certainty, then, are those waking experiences that are at once actually coheren t (thereby essentially dist inguishing them f rom dreams), and that canno t ever present themselves as incoherent (as possibly a dream) because they contain a clear and distinct recognit ion o f the causal sources o f the contents o f the experience.so

Although it is not often noticed, there can be actual waking experiences, presenting themselves as coherent, which nevertheless reveal themselves upon

�9 SThe Latin original of this crucial passage reads: "Cum ver6 eae res occurrunt, quas dis- tincte, unde, ubi, & quando mihi adveniant, adverto, earumque perceptionem absque ulla inter- ruptione cum tot~ reliqut vit~ connecto, plane certus sum, non in somnis, sed vigilanti occurrere" (AT: VII, 9o). And the French texts reads: "Mais Iorsque j'aper~oy des choses dont je connois distinctement & le lieu d'o~ elles viennent, & celuy o~ elles font, & le temps auquel elles m'aparoissent, & que, sans aucune interruption, je puis lier le sentiment que j'en ay, avec la suitte du reste de ma vie,je suis entierement asseur~ queje les apperr en veillant, & non point dans le sommeir' (AT: IX, 71).

The point made by the underlined passages is particularly salient in the French: "lorsque j'aper~;oy des choses dont je connois distinctement & le lieu d'ot~ elles viennent, & celuy ot~ elles font & le temps auquel elles m'aparoissent." See note 28 above.

~o Bernard Williams correctly points out that "'Descartes regards it as self-evident that if I have veridical perceptions, then I have experiences which are caused by things outside myself" (Des- cartes: The Project of Pure Enqui~, 58). For a survey of recent articles defending causal theories of perception, knowledge, memory, and linguistic reference, see S. Davis, ed., Causal Theories of Mind (Berlin" Walter de Gruyter, 1983).


a little reflection to be structurally incoheren t in certain ways and hence as possibly dreamt . So actual waking exper ience toge ther with appa ren t coherence, a l though they are jo indy necessary for the certain recogni t ion o f waking experience, are not sufficient. A good example would be the waking experience o f a work o f art . For instance, not every event in Mr. Pickwick's life, as related in The Pickwick Papers, is accounted for by Dickens. T h u s there are spatial and t empora l discontinuities within the Pickwick-world. Moreover , it is not at all clear whe the r the p o mp o u s and foolish Pickwick o f the early chap- ters is really identical or not with the humble, wise Pickwick o f the later parts o f the book.3, In addi t ion to problems o f identity, there are many aspects o f the Pickwick-world--say the exact n u m b e r o f oversized waistcoats in Mr Pick- wick's l odg ings - - abou t which no t rue or false proposi t ion can be made. T h e Pickwick-world is simply shot t h r o u g h with t ruth-value gaps. Finally, no one answering to the comple te set o f descriptions Dickens gives o f that worthy gent leman ever actually existed. So my exper ience o f r ead ing about Pickwick's life, though waking and seemingly coherent , does not have certainty about my being awake. Ar t exper iences , indeed all exper iences o f the self-conscious fictive imagination, t hough waking and apparent ly coherent , are consistent with the na ture o f d r eam exper iences in their having structural discontinuities, in not always obeying Leibniz's laws o f identity, in having t ruth-value gaps, and in the i r p resuppos ing the nonexis tence of the object o f the experience. So while it is t rue that these are waking experiences, and while I believe that they are waking experiences, and while the a p p a r e n t continuity o f the exper ience justifies the bel ief that these are waking exper iences , I still do not yet know with certainly that these are waking experiences.3 '

Unlike exper iences involving the fictive imagination, however , exper iences containing the clear and distinct recognit ion o f the causal sources o f those experiences gua ran t ee the existence not only o f the causal object o f the experience, but also o f a cont inuous spat io- temporal world beyond the exper iencer , in which the causal object o f exper ience is embedded . Moreover , such experi-

3, Dickens simply seems to have changed his mind about the characterization of Pickwick in the course of writing the monthly imtallments of The Pickwick Papers, leaving the reader with a fictional personal-identity puzzle. See R. L. Patten's Introduction to The Pickwick Papers (Har- mondsworth, Middlesex: Penguin Books, 1972), 11-32.

3, Such experiences are therefore the analogues of Gettier-style counterexamples to the theory that knowledge is justified true befief. See E. Gcttier, "Is Justified True Belief Knowl- edge?" Ana/ys/s a3 (1963): 191-~ 3. My claim is that Descartes is alive to precisely this problem in the context of anti-dream-skeptical arguments, and that that is primarily why he adds the clearly and distinctly known causal-source condition. For a similar move in connection with Gettier examples, see Alvin I. Goldman, "A Causal Theory of Knowing,"Journa/of Philosophy 64 (1967): 357-7% and "Discrimination and Perceptual Knowledge," Journal of Philosophy 73 (1976): 771- 9 t . Goldman is officially agnostic as to the impact of his account on skepticism.

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ences (by way of their distinctness) guarantee the discriminability of the causal object from other objects within the experience. Such actually coherent experiences could not possibly be confused with dreaming experiences because they involve an existential commitment to the object of the experience as embedded in a spatio-temporally coherent world, and contain neither truth-value gaps nor indiscriminable objects. Therefore such experiences are not only actually coherent and apparently coherent; they are also known with certainty to be waking.

Although the causal-source criterion is sufficient to tell the difference between waking and dreaming with certainty, it is important to recognize that it does not also seem to be necessary. There would appear to be experiences recognized with certainty to be waking, which do not in addition (in that experience itself) contain a clear and distinct intuition of the causal source of that experience. An example would be a geometrical demonstration employ- ing a diagram. As Locke points out in the Essay: "And though mathematical demonstrations depend not upon sense, yet the examining them by Diagrams, gives great credit to the Evidence of our Sight, and seems to give it a Certainty approaching to that o f the Demonstration itself. For it would be very strange, that a Man should allow it for an undeniable Truth, that two Angles of a Figure, which he measures by Lines and Angles of a Diagram, should be bigger one than the other; and yet doubt of the Existence of those Lines and Angles, which by looking on, he makes use of to measure that by."3s What Locke is saying is that the experience of doing geometric proofs using diagrams presupposes the reliability of the external senses under normal, waking conditions. This reliability is imputed to the present experience of demonstrat- ing. So the actual carrying out o f such a diagram-assisted proof gives me certainty that I am now awake without there actually being a clearly and distinctly perceived external causal source for the experience. To be sure, the reliability of the senses does entail that there be some experiences containing clear and distinct perceptions of causal sources. So, in general, waking experiences recognized with certainty presuppose some clear and distinct intuitions of causal sources. But not every single certainly recognized waking experience is itself also an experience containing (in the experience itself) a clear and distinct causal-source intuition.

It is to be particularly noted here that this Lockean point does not violate Descartes's assumption that geometric propositions hold true in dreams: "Whether I am awake or a s l e e p . . , a square has no more than four sides. It seems impossible that [even in a dream] such transparent truths should incur

ssJohn Locke, An Essay concerning Human Understanding, ed. P. H. Nidditch (Oxford: Claren- don Press, 1975), Book IV, Chapter t 1, p. 633.

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any suspicion of being false" (CSM: II, 14; AT: VII, 2o). It is one thing to hold that geometric propositions can be true in dreams, and another to claim that they can be demonstrated to be true in dreams. Because of Descartes's unusual modal doctrine to the effect that the necessity of mathematical propositions depends exclusively on God's wi11,34 there can for him be mathematical truths that are not humanly demonstrable. Descartes is not therefore committed to the necessary demonstrability of geometrical truths either in waking or dreaming experience, and so Locke's point is perfectly consistent with Descartes's views on dreaming and geometry.

To conclude, then. Descartes's argument in the last paragraph of the sixth Meditation, against the epistemological dream skeptic, claims that we can sometimes distinguish with certainty between waking and dreaming, under the following epistemic conditions: (1) that the experience appear coherent; and (9) that there be a dear and distinct recognition of the causal source of the experience. The coherence criterion is necessary but not sufficient for this certainty; the causal-source criterion is sufficient but not necessary; and the two of them are .jointly necessary and sufficient.

To be sure, God ultimately plays a role in this argument because he certi- fies clear and distinct intuitions. I f the intuitions about causal sources were misleading, then GOd would have to be a deceiver. But of course by the end of the Meditations Descartes assumes not only that GOd exists (on the basis o f his three proofs) but also that God is not a deceiver (on the basis o f his familiarity with his innate idea of God).

.

It is quite obvious that my reconstruction of Descartes's argument against epistemological dream skepticism will not satisfy anyone who refuses to grant the legitimacy of any appeal to clear and distinct perception or to the epistemological function of God in guaranteeing the rule relating clear and distinct intuitions to the truth. Hobbes, for example, points out that Descartes's antiskeptical argument seems to imply that "an atheist cannot infer that he is awake on the basis of memory of his past life" (CSM: II, 137; AT: VII, 196).

Nevertheless my reconstruction does, I think, provide for a much more plausible and effective argument than the standard interpretation has granted Descartes. There are two main reasons for this. First, my interpretation avoids attributing to Descartes the patently silly claim that, necessarily, every apparently coherent experience is a waking one. And secondly, my interpretation relates clear and distinct intuition, as employed by Descartes in his anti-dream-

See De~ar tes ' s famous letter to Mersenne in Kenny, ed., Descartes: Philosophical Letters, t 3 - 14 �9

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skeptical a r g u m e n t in the sixth Meditation, to causal facts a b o u t the sources o f an e x p e r i e n c e - - n o t to m e r e psycho log ica l facts a b o u t the c o n n e c t i o n b e t w e e n a p p a r e n t exper ien t i a l c o h e r e n c e a n d be ing awake. B racke t i ng H o b b e s i a n d o u b t s a b o u t the tenabil i ty o f a n y appea l to clear a n d dist inct in tu i t ion (and h e n c e to G o d ' s nondece i t fu lness ) , t h e r e w o u l d seem to be a fairly we igh ty phi losophica l p r e s u m p t i o n in f a v o r o f c lear and dist inct k n o w l e d g e o f facts basic to physical science (or p sychophys i ca l science), as aga ins t c lear a n d dis- t inct k n o w l e d g e o f facts de r ived f r o m in t rospec t ive p sycho logy alone. I n d e e d , consis tent ly with m o d e r n d e v e l o p m e n t s in cogni t ive science a n d "na tu ra l i zed ep i s t emology , " p e r h a p s an a r g u m e n t s t ra tegy very s imilar to Descartes 's c o u l d be devised which did no t f ind it necessa ry to appea l to c lear a n d dis t inct in tu i t ion o r to God , bu t r a t h e r on ly to m o r e natural is t ic ways o f r e c o g n i z i n g the causal sou rce e m b e d d e d in cer ta in m e n t a l contents.s5 T a k e n in c o n j u n c - t ion with the p r o p e r r e a d i n g o f Descar tes ' s very de fens ib le cons t rua l o f the role a n d m e a n i n g o f the c o h e r e n c e - s t r u c t u r e cr i te r ion , this m i g h t well give s o m e close r e a d e r o f Descar tes ' s a r g u m e n t in the last p a r a g r a p h o f the s ixth Meditation the last l augh at the ep i s temolog ica l d r e a m skeptic.s6

University of Colorado at Boulder

s5 Accounts such as those offered by Goldman in "A Causal Theory of Knowing" and "Dis- crimination and Perceptual Knowledge" might well be employed in such an argument strategy. See note $2 above. In particular, Goldman does not require that the knower of a causally motivated belief be able to supply a rational justification for her belief. It may, however, be arguable 0) that all appeals to causal realism are implicitly committed to some form of scientific essentialism, (2) that scientific essentialism is implicitly committed to a doctrine of rational intuition, and (3) that any defensible doctrine of rational intuition must appeal to a divine justification. On the first point, see Locke, An Essay com=erning Human Understanding, IV, 4, 568-69 �9 On the second point, see George Bealer, "The Philosophical Limits of Scientific Essentialism," Philosophical Per- spectives I (1987): a92: "At least one of the philosophical propositions used in the fully elaborated presentation of scientific essentialism can be known to be necessary without the aid of empirical science." And on the third point, see the third and fourth Meditations. If this three-step argument goes through, then perhaps Descartes's own version of this antiskeptical argument may prove to be the most lucid, when all is said and done. The price of answering the skeptic, under the assumption that knowledge requires metaphysical certainty, may well be an investment in divine real estate.

I would like to thank Gareth Matthews, and two anonymous referees for this journal, for extremely helpful comments on earlier drafts of this paper.

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Descartes and Dream Skepticism Revisited