William G. Lycan


In the 1950s and -60s, we used to hear a good deal about Moore’s alleged refutation of skepticism and his famous proof or "proof" of an external world. Papers on that topic had titles like "Moore Against the Skeptics." Some of the commentary was sympathetic, some critical. But the New Skepticism of the 1970s abandoned whatever sympathy Anglo-American philosophy may have had for Moore. In "Why Not Skepticism?,"1 Keith Lehrer paused to bash Moore, as did Peter Unger in "An Argument for Skepticism."2 Fellow travellers such as Barry Stroud3 have added opprobrium of their own. And Moore has since been left for dead.

       My purpose in this paper is to resuscitate Moore's defense against skepticism, or at least to show that the New Skeptics unanimously misconstrued and underrated it. Whether or not Moore succeeded in refuting skepticism, his argument has hardly even been considered, much less rebutted.

       I am going to offer an interpretation of Moore that I believe makes him maximally powerful against the skeptic. This paper is not a foray into professional Moore scholarship, so I am not to be refuted by the citing of seemingly contrary textual passages, unpublished Nachlass, private correspondence, etc. (Though I am personally pretty sure that my interpretation is correct; see the quotations collected in the Appendix.)

       1. Notoriously, Moore responded to skepticism about the external world by holding up his hands. "Here is one hand, and here is another." (We are told that Moore made "a certain gesture" with each of the hands as he said this.) Adding the uncontentious premise that hands are things external to our minds, he called the result a "proof" of the existence of external objects, indeed a "perfectly rigorous" proof, adding that it is probably impossible to give a better or more rigorous proof of anything.4 Now, presumably, the production of a perfectly rigorous proof that P is an adequate response to someone who has expressed skepticism as to whether P; for what else could the skeptic be demanding? Moore seemed to waver on the question of whether this response to the skeptic is utterly conclusive, but he certainly believed it to be adequate.

       Moore’s technique was in some favor for a while. In the 1940s and -50s it was assimilated and reconfigured by the Ordinary Language philosophers, notably by Norman Malcolm and Alice Ambrose,5 though the Ordinary Language interpretation was vigorously repudiated by Moore himself.6 But the Ordinary Language period ended sometime during the ‘60s, and soon after (I suppose predictably) skepticism reared its head again. The ‘70s’ New Skepticism offered some genuinely new skeptical arguments. But the New Skeptics also were concerned to reject Moore and to expose his appeal to common sense as specious, quite apart from their new skeptical arguments.

       Thus Lehrer:

The reply of the dogmatist [=, merely, the nonskeptic] to such [skeptical] imaginings might be that we are not only justified in those basic beliefs, we are also justified in rejecting any hypothesis, such as the sceptical one, which conflicts with those beliefs. But the sceptic may surely intercede long enough to protest that he has been ruled out by fiat. The beliefs of common sense are said to be basic and thus completely justified without any justificatory argument. But why, the sceptic may query, should the dogmatist’s beliefs be considered justified without argument and his hypothesis be rejected without argument? Dogmatists affirm that the beliefs of common sense are innocent until proven guilty, but why, the sceptic might inquire, should his hypothesis not receive comparable treatment before the bar of evidence? Why not regard the sceptical hypothesis as innocent until proven guilty? Indeed, the sceptic might continue, why not regard all belief as innocent until proven guilty?…

Thomas Reid was wont to argue that the beliefs of common sense had a right of ancient possession and were justified until shown to be unjustified. But such epistemology favors the sentiments of conservative defenders of the status quo in both philosophy and politics. [pp. 292-93]

Stroud: In his ‘proof of the external world’ Moore held up his hand and said ‘Here is one hand’ and ‘Here is another’, and he concluded that therefore there are at least two external things. And since, as he claimed, he certainly knew his ‘premises’ and concluded validly from them that external things exist, he thought he had proved that there is an external world.

I have said that I think it will be felt that this ‘proof’ does not amount to a demonstration of the falsity of philosophical scepticism or of the truth of an affirmative answer to the philosophical question of whether we can ever know whether anything exists ‘outside us.’ Here I do no more than appeal to your own sense of the issue, since I confess it would be difficult to demonstrate its failure to someone who feels no deficiency in Moore’s ‘proof.’ But I ask you to consider whether you initial response is not that, considered as an answer to the philosophical question of knowledge, Moore’s assertions are unjustified--in that context they are simply dogmatic and without probative force. It is known at the outset of the philosophical inquiry that people frequently think and often claim they know things in circumstances as ‘favourable’ as those in which Moore found himself. The question is whether they do know what they think they know on those occasions, and if so, how. The considerations which have traditionally been thought to lead to a negative answer must somehow be dismissed or accounted for before the philosophical question will have been answered or exposed as illegitimate. [p. 279]

Three different charges or objections are made here. 1) The usual: that Moore is simply begging the question. [Both Lehrer and Stroud.]

2) That a proposition’s being commonsensical confers no special status—neither sanctity, nor even a presumption in the proposition’s favor. [Lehrer.]

3) That one cannot dismiss skeptical arguments so brusquely, without providing a (somehow) deeper and "more philosophical" answer to the skeptic. [Stroud; we shall return to this point at some length.]

And Peter Unger adds a fourth: 4) That Moore is being dogmatic in the pejorative sense. Moore thinks he has a right to hold common-sense beliefs come what may, but [Unger argues, by giving some convincing examples] no one ever has any right to hold any belief come what may. [pp. 247ff.]

       I shall offer my interpretation of Moore, and then answer each of these four charges.

       2. Remember how Moore used to argue against idealists and other anti-realists (as well as against skeptics). In considering an anti-realist view, he would first draw from it a very specific negative consequence regarding his own everyday experience. E.g., take the idealist claim that time is unreal. From it, Moore would deduce that he, Moore, had not had his breakfast before he had his lunch--beforeness being a paradigm case of a temporal relation. (Some scholarly work was put in, in order to assure us that the idealist claim was intended in such a sense as to have that consequence.7)

       Now, consider the idealist’s defense of the idealist claim about time. Let us charitably suppose that the defense had taken the form of a deductively valid argument. The argument must of course (on pain of regress) have had premises. So it is an argument that looks schematically like this:

(P1) ....

(P2) ....

. [steps] .


... (C) Time is unreal. QED
--to which we may add as a corollary, ... (C') I did not have breakfast before I had lunch.          By hypothesis, the argument is valid. But that is to say only that each of the sets {P1,...Pn, ~C} and {P1,...Pn, ~C'} is inconsistent. The idealist of course wants us to accept P1-Pn and therefore to accept C and reject ~C on the strength of them. But nothing in the argument itself forces us to do that, since if we wish to deny its conclusion we have only to reject one of the premises. Any argument can be turned on its head.

       More generally--in fact, throughout philosophy and every other subject--a deductive "proof" can be no more than an invitation to compare plausibility: Of the propositions P1,...Pn, and ~C, which is the least plausible?

       Applying that crucial question to any specific argument for idealism concerning the external world, Moore thought it scarcely left room for debate. Since ~C, the reality of time, is directly entailed by something Moore already knows to be true (~C', that he did have his breakfast before he had lunch), the culprit must be one of the other members of the inconsistent set; it must be one of the premises that is false. It may be interesting to continue our plausibility survey and decide which of the Pi is less plausible than the rest; in fact, surely it will be instructive and illuminating to do that. But that is not necessary in order to vindicate our common-sense belief in the reality of time. For the latter philosophical purpose, it does not matter which of the Pi is false. In fact, we do not even have to know what the argument's premises are exactly; whatever they are, they cannot all be true. The idealist was doomed from the start.

       So too with external objects. The reality of material objects is entailed by something Moore already knows to be true, that he has hands); so any philosophical argument designed to show that there is no external world must be unsound, period.8

       3. I have deliberately made Moore sound closed-minded, dogmatic, pigheaded. And many philosophers have rejected his style of argument on just that ground, finding it obvious that Moore is just begging the question against his opponent and pretty crassly too. But it is important to see that Moore is doing no such thing. He is only modestly inviting a plausibility comparison. The comparison is, in effect, between (a) "I had my breakfast before I had lunch" and (b) a purely philosophical premise such as McTaggart’s assumption, "Temporal modes such as pastness and futurity are monadic properties of events." Come, now: How could a proposition like (b) be considered as plausible as (a)? How could I possibly be more certain that "temporal modes are monadic properties of events," than that I had breakfast before I had lunch today? (In the case of external objects, the comparison is between "Here is one hand and here is another" and, in one case (McTaggart also), "Every existent thing has proper parts that are substances.") These are no-brainers. And it is important to note that no particular criterion of plausibility, credibility or comparative certainty is or need be invoked; (a) beats (b) by any reasonable standard whatever.9

       We may wonder where metaphysical premises (often called "intuitions") come from. Are they deliverances of the lumen naturale? Does the Third Eye of the metaphysician’s mind get a rare look at a Platonic Form? Perhaps they just articulate features of our ordinary ways of conceiving certain things. Whatever; their epistemic credentials are obscure, and more importantly, they are shoddy. A metaphysician who claims to "just know" that such an abstract premise is true ("This is a deep intuition") cannot be taken very seriously. But Moore has excellent grounds for the competing proposition (a): He always has breakfast before he has lunch, and he specifically remembers doing so today in particular. A forced choice between (a) and (b) has got to favor (a).

       Even so, is Moore clinging to his humdrum common-sense beliefs come what may? Is common sense then sacred and utterly irrefutable? Is that not precisely what Our Founder Socrates taught us to leave behind, indeed to snicker at? And, remember, it used to be "common sense," as obvious as practically anything, that the earth is flat and motionless, and that the sun rises and gradually travels westward to pass over our heads.

       This is a second standard misinterpretation of Moore. Moore did not hold that common sense is irrefutable. Common-sense beliefs can be corrected, even trashed entirely, by careful empirical investigation and scientific theorizing.10 Exploration (in the literal sense) and astronomy have teamed up to show that, despite appearances, the earth is a spheroid that moves around the sun and that "up" means only "away." So too, chemistry and physics have shown that the most "solid" granite boulder is actually a region of almost completely empty space, populated only by some minuscule and invisible particles racing through it at unimaginable speeds.

       But philosophers (especially idealist philosophers) are not explorers or scientists. McTaggart provided no evidence for his claim that temporal modes are monadic properties of events; it just seemed true to him, for some reason. Common sense must yield to evidence, as I have said, but it need not yield to bare metaphysical pronouncement. Moreover, as is notorious, a priori metaphysical views historically have little staying power; one philosophical era’s fundamental principles are often rejected in the next era as ludicrous superstition. No purely philosophical premise can ever (legitimately) have as strong a claim to our allegiance as can a humble common-sense proposition such as Moore’s autobiographical ones. Science can correct common sense; metaphysics and philosophical "intuition" can only throw spitballs.11

       Just as there is no such thing as an idealist argument that does not appeal to some abstract metaphysical or epistemological principle that is simply assumed without defense, there is no such thing as a skeptical argument that does not do the same thing. Which is to say that there is no good reason to accept the argument; the unargued principle is only philosophy stuff. Even if the principle does seem true to us when first we consider it--at the particular temporal and geographical point in the history of philosophy, and well cossetted amid the philosophical community we happen to inhabit and its defining fads--there is no rational ground for pledging allegiance to it in preference to a plain truth of common sense.

       (Someone might think of claiming that such a principle is analytic, or a somehow "conceptual" truth, and so not in need of defense. But even if one is unpersuaded by Quine and actually believes in analytic or conceptual truths, the appeal will not help the skeptic here. No one who reasonably thinks that the principle in question is false is going to be converted by the bare assertion that the principle is analytically true.)

       That disposes of (1), the charge of question-begging.

       4. Does Moore arbitrarily privilege commonsense propositions, investing them with an ancient right of possession or some other form of epistemic sanctity? His proof of the external world may suggest that he does, because all we can yet see to mark "Here is one hand…" as skeptic-resistant is, its being a commonsense proposition.

       At this point I believe we must acknowledge a complication in Moore’s response to the skeptic. Originally I portrayed Moore as responding by producing a proof of the proposition in regard to which the skeptic’s skepticism was directed. And he certainly did intend that at the time, but he has what I think is a more powerful strategy as well: namely, to include among the class of commonsense propositions, not only first-order observations like "Here is one hand…" and "I had my breakfast before I had lunch," but also knowledge-claims directed upon those and other observations as well. "I know that my name is William G. Lycan," "I know that I am giving a talk right now," and "I know that I am wearing glasses" qualify along with "I know that I have hands" and "I know that I had my breakfast before I had lunch.12

       On this interpretation, it is not that "I have hands" etc. are known in virtue of their being commonsense propositions. It is that the relevant knowledge-claims themselves are more plausible than are the premises of any philosophical argument intended to show that they are false. So, on this interpretation, Lehrer’s objection (2) is a rubber arrow.

       5. Objection (3) demands a "more philosophical" answer than Moore’s. But the Moorean position (my version of it anyway) is that attempts at "philosophy" in the sense intended are quixotic and a bit pathetic. Philosophy in that sense is a kind of "first philosophy"; it would have to be the deliverance of some distinctive faculty higher and more authoritative than our ordinary perceptual and cognitive faculties and our common sense. It is supposed to have the vantage point and the power to critique those lower faculties and to show that, whatever their undeniable usefulness for getting us around the everyday world, they cannot unlock the door to the deeper, more profound world of what is really, strictly and ultimately true as opposed to merely plausible or convenient to believe.

       But there is no such faculty. The most powerful probative tool we have is the deductively valid argument, and even a deductively valid argument is at best a comparison of plausibility. (Remember, we are assuming that the skeptic’s back is to the wall—that the premises Pi have no further argumentative support. On pain of regress, there must be such premises.) There is a persistent feeling among some philosophers, Stroud among them, that Moore’s answer to the skeptic is shallow and superficial, and that a deeper response is required. But if there is no deeper or more fundamental philosophical method than the deductive argument, what form could it possibly take? To put it provocatively, I maintain that there is nothing deeper in all of philosophy than Moore’s response to the skeptic.

       Stroud says, "In the [philosophical]... context [Moore’s claims] are simply dogmatic and without probative force." But notice that this is not responsive. It simply does not address Moore’s plausibility comparison, once we realize that the ordinary knowledge-claim is one term of the comparison. To respond (at all), Stroud would have to produce the relevant skeptical argument; consider each of its premises, and ask whether the premise is really more plausible than that I know I have hands. He has not done any such thing.

       The main premise of Stroud’s own skeptical argument is that "if somebody knows something, p, he must know the falsity of all those things incompatible with his knowing that p (or perhaps all those things he knows to be incompatible with his knowing that p)" (pp. 29-30). That is,

For every logical possibility q: [Ksp & ¨~(Ksp&q)] Þ Ks~q, or perhaps
[Ksp & Ks¨~(Ksp&q)] Þ Ks~q.
But this principle is already highly controversial, since like the infamous "KK" thesis it requires a knower to have (however tacitly) a certain attitude directed upon her/his own knowing. Nor would the skeptic gain much by retreating to a simpler, lower-level closure principle, such as the more common [Ksp & Ks¨~ (p&q)] Þ Ks~q; for in light of weaker, contexualist alternative versions of such principles (obtained á la Peirce and Dewey by restricting the universal quantifier to possibilities that are "real" or "relevant" or "non-idle" in the context), we have no reason to accept Stroud’s unrestricted, very strong version at the price of "I know I have hands."13

       Finally, the fourth charge (Unger’s) was that Moore is being dogmatic, insisting on holding common sense beliefs come what may. But Moore is doing no such thing. He does not contend that common sense is immune to science. He does not even deny that everyday beliefs held with great confidence have sometimes proved to be mistaken. His claim, on my interpretation, is only that at any given time, some of my knowledge claims will be more plausible, and rationally more credible, than are the purely philosophical premise(s) of any skeptical argument.

       Michael Williams has complained14 correctly that even if successful, Moore’s argument is not illuminating; it may stiffarm, even refute, the skeptic, but it does not show what is wrong with skeptical arguments and it certainly does not advance positive epistemological theory. Williams contends that an adequate response to skepticism should do these things.15 I say, yes and no. If skepticism can tenably be rebutted, that is itself an important philosophical achievement; and I believe Moore has shown that no good reason has ever been given for accepting skepticism.

       It would be even better also to parlay one’s antiskeptical rebuttal into an illuminating diagnosis and a positive epistemological view. Moore has not done that. As I have expounded him so far, emphasizing his unconcern for the skeptic’s exact premises and other details, he has almost ostentatiously declined to do so. But Gilbert Harman has pointed out16 that epistemological headway can be made if we assemble a number of attractive skeptical arguments and not only turn them on their heads but consider carefully which of their premises should be denied, and why. In this way, taking the negations of those premises and the reasons for the denials, a positive epistemology may be suggested.

       So there is a minimal Moorean position, that merely (though justifiedly) rebuts the skeptic without providing further light, and there is Harman’s more positive project. Each is valuable. And of course the former does not obstruct the latter, but nicely paves its way. My concern here is to defend the minimal position, but I am an enthusiastic fan of Harman’s as well.

       6. I know of one major exception to my claim that Moore’s argument has hardly even been considered. In his book, but merely in passing, Stroud characterizes Moore’s position as follows (SPS, p. 106).

For Moore the question of which conclusion to accept therefore comes down to the question of whether it is more certain that he knows that his pencil exists or that Hume’s two ‘principles’ are true. Moore thinks it is obvious that it is more certain that he knows that his pencil exists. His aim is pretty clearly to refute Hume’s philosophy by relying on the procedure of retaining what is known or is more certain when it conflicts with what is less certain. Stroud responds by reference to an example he has sketched previously (pp. 102-03). In the example, a young duke has been murdered in an English country house, and the crime is being investigated by a master detective and his eager but inexperienced and impetuous apprentice. Now (p. 108), Imagine a slightly later stage in the investigation of the murder. The apprentice, properly chastened, tries to be thorough and systematic and decides to consider everyone who could possibly have committed the murder and to eliminate them one by one. He gets from the duke’s secretary a list of all those who were in the house at the time and with careful research shows conclusively and, let us suppose, correctly that the only one on the list who could possibly have done it is the butler. He then announces to the detective that he now knows that the butler did it. ‘No,’ the master replies, ‘that list was simply given to you by the secretary; it could be that someone whose name is not on the list was in the house at the time and committed the murder. We still don’t know who did it.   ...It would obviously be absurd at this point for [the apprentice]...to try to reject what the detective said by appealing to his ‘knowledge’ that the butler did it. The detective said that even after all the apprentice’s valuable work they still do not know who committed the murder, and the apprentice cannot reply by saying ‘No. You’re wrong because I know the butler did it’. And is that not precisely Moore’s own dialectical position?

       Later (p. 111) Stroud returns to his theme of a deep philosophical critique of common sense:

If there can be a general assessment of our knowledge of the sort the philosopher engages in, and if the most careful execution of that assessment leads to the conclusion that we never know of the existence of material objects, Moore’s attempt to argue against that conclusion by appealing simply to his knowledge that this pencil exists would indeed be like the apprentice’s ludicrous response to the detective. He would be trying to deny the correctness of the assessment by appealing to one of the pieces of ‘knowledge’ that had been called into question by that very assessment.   From the ‘assumptions’ said to be behind [Hume’s or] Russell’s skeptical conclusion[s] it does indeed follow that Moore does not know that this is a pencil. But if those ‘assumptions’ are nothing more [sic; surely Stroud means less] than truths unavoidably involved in any general assessment of our knowledge of the world, Moore does not successfully refute them any more than the apprentice refutes the detective.          I make two rejoinders on Moore’s behalf.

       (I) Stroud’s argumentum ad apprenticium is no more responsive to my Moorean argument than was his original objection. Again, to respond—at all, much less adequately--he would have to produce a particular skeptical argument and actually carry out the plausibility comparison. He has not done that. For the record, in his book (Ch. 1), he does produce a particular skeptical argument, so we can make the plausibility comparison for ourselves; I have recorded its main premise in section 5 above, and noted how easily (and reasonably) it can be and has been resisted.

       But what if a skeptical argument’s premise is, indeed, a "truth unavoidably involved in any general assessment of our knowledge of the world"? If established, that would do the trick, to be sure. But merely to insist that Stroud’s own main premise is such a truth would beg the question; we would need to be given some argument to show why the premise is not only true but unavoidably involved in any general assessment of our knowledge of the world--and the regress is off and running.

       More generally, it is often claimed that the skeptic’s premise is not made-up philosophy stuff, but is already--if not analytic, unavoidably involved in assessment of our knowledge of the world, or itself common sense--tacitly accepted by philosophers and by ordinary people everywhere.17 On this view, the skeptic is not dragging in some disputable philosophical premise, but is launching a fair and sound ad hominem against the nonskeptic. Wrong, and/or question-begging, again: Who says we all accept the premise? The historical fact is that we do not all accept it, and we are not all being obviously irrational. At the very least, argument is needed, and the argument itself is sure to have some distinctively philosophical premise.

       (II) The apprentice example is not in fact a good analogue for Moore’s argument. Of course the apprentice cannot claim to know that the butler did it, because his case is badly flawed in a way we all recognize: he has been credulous in simply accepting the secretary’s list, when after all the secretary is himself a suspect and at the very least may be an accomplice. The apprentice is not yet even a minimally competent detective, much less a knowledgeable one. But my belief that I have hands is not based on any such gaffe. No one but a professional philosopher would think of questioning it.

       Of course, Stroud thinks I am being credulous, perhaps culpably so, in continuing to believe I have hands once the skeptical possibilities have been called to my attention. But that is just what needs to be shown. The apprentice analogy cannot stand on its own. By itself it is no objection to Moore.18

       7. It may appear that I have left one bit of business unfinished, indeed that my crucial move remains undefended: Are knowledge claims really common sense propositions? Of course "I have hands" is a common sense proposition, but my Moorean argument seems to depend on the bolder thesis that "I know I have hands" is a common sense proposition.

       This worry is importantly confused. At least officially, my Moorean argument does not include the claim that "knowledge claims are common sense propositions." It asserts only that some knowledge claims, whatever other properties they may have, are more credible than are the distinctively philosophical premises of skeptical arguments aimed against them. And especially, as before against Lehrer’s charge (2), I emphasize that Moore makes no argument from any proposition’s being commonsensical to that proposition’s having any positive epistemic status.

       Still, in assimilating "I know that I have hands" to "I have hands," I have made a dialectically significant move. Is it so obvious that the plausibility of "I know that I have hands" is in the same league as that of the logically much weaker "I have hands"?19 Perhaps the assimilation should be motivated a bit further.

       Stroud does not officially contest it. But he persistently emphasizes a fact that might be taken to cast doubt on it: namely our attraction to skeptical arguments in the first place. Many, perhaps most, philosophers feel the pull, feel the worry, feel the need to find a hole in the argument or at least to fend the skeptic off. (The same is not true of McTaggart’s argument against the reality of time; that argument is far from being in any way intuitive.) Of course, philosophers are less credulous than the general public, so we may be unnaturally vulnerable to the skeptic. Undergraduates vary: some do feel the attraction (or the fear) right away, but others find it impossible to take Descartes’ Meditations seriously. (Of course undergraduates are not representative of the general public either, because they--sophomores especially--are engaged precisely in the business of learning to question everything, either by inclination or from duty.) What about the truly general public? Don’t ask me. How would I know?

       In any case, I have not shown that any knowledge claims have the sort of plausibility that their complements do. Short of offering a philosophical theory of comparative plausibility, how might I motivate that?

       Let us ask what it is that marks a proposition as Moorean-commonsensical. That question is seriously underinvestigated by Moore aficionados. Without pretending that the category has sharp boundaries, I offer the following. My characterization is deliberately very conservative, in counting fewer beliefs as commonsensical even than Moore himself did.20

(i) A common sense proposition is about something noted by someone at a particular place and time. But

(ii) it has a weak generalization (w.g.), a general proposition of which it is an instance and to which the overwhelming majority of humankind would assent were that generalization put to them in the appropriate language--e.g., "Some things happen before other things do."

(iii) Neither it nor its w.g. contains technical concepts of any sort or concepts that require special schooling to acquire (and the concepts occur literally rather than in any stretched or analogical sense).

(iv) No matter what s/he might say on whatever ideological or other theoretical grounds, everyone or virtually everyone accepts one or more instances of its w.g.

(v) Its w.g. is too obvious to mention; to state the w.g., just like that and out of context, would be a conversational solecism.

(vi) To deny its w.g., in the absence of any special stage-setting, would be to give evidence not that one was mistaken but that one was psychologically abnormal. (Moore was struck by the fact that the views of variously idealist and skeptical philosophers are the sorts of propositions belief in which, by nonprofessionals, tend to get one a nice shot of thorazine and a long ride in a van.)

(vii) There is an ineradicable tendency to go on believing it, its w.g., or another of its w.g.'s instances, even when one is presented with convincing indirect evidence that it is false.21)

       How does "I know I have hands" fare? I think it clearly satisfies all these criteria except (vii). Stroud has cast some doubt on (vii), because as he says, some people feel the pull of skepticism, in a way that virtually no one feels any attraction to anti-realism about time. But (vi) out of (vii) ain’t bad.

       I do not say that Moore’s argument is conclusive. I do contend that so far as has been shown, it is an adequate response to the skeptic--which is a good deal more than has been conceded to it for the past forty years.22

Appendix: Moore speaks

But it seems to me a sufficient refutation of such views as these, simply to point to cases in which we do know things. This, after all, you know, really is a finger: there is no doubt about it. And I think we can safely challenge any philosopher to bring forward any argument in favour either of the proposition that we do not know it, or of the proposition that it is not true, which does not at some point, rest upon some premise which is, beyond comparison, less certain than is the proposition which it is designed to attack. The question whether we do ever know such things as these, and whether there are any material things, seem to me, therefore, to be questions which there is no need to take seriously: they are questions which it is quite easy to answer, with certainty, in the affirmative.  
--"Some Judgments of Perception"23

That is why I say that the strongest argument to prove that Hume’s principles are false is the argument from a particular case, like this in which I know of the existence of some material object. And similarly, if the object is to prove in general that we do not know of the existence of material objects, no argument which is really stronger can, I think, be brought forward to prove this than any particular instances in which we do in fact know of the existence of such an object.

--"Hume’s Theory Examined"24

I cannot help answering: It seems to me more certain that I do know that this is a pencil and that you are conscious, than that any single one of these four assumptions is true, let alone all four... I agree with Russell that (1), (2) and (3) are true; yet of no one even of these three do I feel as certain as that I do know for certain that this is a pencil. Nay more: I do not think it is rational to be as certain of any one of these four propositions, as of the proposition that I do know that this is a pencil.

--"Four Forms of Scepticism"25
University of North Carolina


1 ‘Why Not Skepticism?’, Philosophical Forum 2 (1971): 283-98; reprinted in G. Pappas and M. Swain (eds.), Essays on Knowledge and Justification (Ithaca, NY: Cornell University Press, 1978) and in M.F. Goodman and R.A. Snyder, Contemporary Readings in Epistemology (Englewood Cliffs, NJ: Prentice-Hall, 1993).

2 ‘An Argument for Skepticism’, Philosophical Exchange 1 (1974): 131-55; reprinted in Goodman and Snyder, op. cit.; page references are to the reprint.
       Interestingly or not, the third best known New Skeptic, I.M. Oakley (‘An Argument for Skepticism concerning Justified Beliefs’, American Philosophical Quarterly 13 (1976): 221-28) does not mention Moore.

3 ‘The Significance of Skepticism’, in P. Bieri, R.-P. Horstmann and L. Kruger (eds.), Transcendental Arguments and Science (Dordrecht: D. Reidel, 1979); The Significance of Philosophical Scepticism (Oxford: Oxford University Press, 1984, hereafter SPS).

4 ‘Proof of an External World’, in Philosophical Papers (London: George Allen & Unwin, 1959), p. 146.

5 N. Malcolm, ‘Moore and Ordinary Language’, in P.A. Schilpp (ed.), The Philosophy of G.E. Moore (LaSalle, IL: Open Court Publishing, 1942); A. Ambrose, ‘Moore’s Proof of an External World’, ibid.; also, M. Lazerowitz, ‘Moore’s Paradox’, ibid.

6 ‘A Reply to My Critics’, in Schilpp, op. cit.

7 Though certainly it has been disputed that McTaggart, for example, did intend this.

8 In all this Moore was strongly influenced by Thomas Reid; but he did not buy into Reid’s containing psychoepistemological system of "first principles," innate belief production mechanisms, etc., and it is important to see that neither that system nor any other is needed to license Moore’s antiskeptical move as presented here.
       Some cynic (it was not Ambrose Bierce, I’ve checked) once defined "faith" as: believing to be true what one knows to be false. Moore might have explicated idealist and skeptical philosophy as, believing to be false what one knows to be true.
       For quite a different antiskeptical reading of Moore, see E. Sosa, "Reflective Knowledge in the Best Circles," Journal of Philosophy 94 (1997): 410-30, and "How to Defeat Opposition to Moore," Philosophical Perspectives 13 (1999): 141-53.

9 Peter Markie has pressed me on this point. I maintain that although the psychological basis and normative authority of "plausibility" judgments are thorny and important philosophical issues, they are just that—philosophical issues. Actual, real-life plausibility comparisons do not wait upon them. (That I and other people often drink water is more plausible than that people often drink Laphroaig, or that more people drink champagne than drink vodka, or that there is no life anywhere else in our galaxy, or that the cause of an idea must have at least as much formal reality as the idea itself has objective reality. Period; I do not have to have any particular philosophical theory of plausibility in order to be entirely justified in making such judgments, any more than I have to have a particular philosophical theory of meaning in order to know what someone has just said.) Of course, there will be rightly controversial borderline cases.

10 See, e.g., "What Is Philosophy?," in Some Main Problems of Philosophy (New York: Collier Books, 1953).

11 In saying this, I am not assuming a clear distinction between theoretical science and metaphysics, nor do I believe in any such distinction. But that is to say only that there are borderline cases.

12 Support for this point of my interpretation (especially) is found in the passages quoted in the Appendix.

13 See, e.g., Fred Dretske, ‘Epistemic Operators’, Journal of Philosophy 67 (1970): 1007-23; Robert Nozick, Philosophical Explanations (Harvard University Press, 1981); Colin McGinn, ‘The Concept of Knowledge’, in P. French, T.E. Uehling and H. Wettsein (eds.), Midwest Studies in Philosophy IX: Causation and Causal Theories (1984); and especially Mark Heller, ‘Relevant Alternatives and Closure’, Australasian Journal of Philosophy 77 (1999): 196-208. But three important qualifications are needed here. First, Moore himself accepted a closure principle, though he turned the skeptical argument from closure on its head; see, e.g., the concluding section of "Certainty," in Philosophical Papers (New York: Collier Books, 1962). Second, some contextualists such as Stewart Cohen ("How to Be a Fallibilist," Philosophical Perspectives, Vol. 2 (1988): 91-123) and Keith DeRose (‘Solving the Skeptical Problem’, Philosophical Review 104 (1995): 1-52) have worked to save the letter of one closure principle or another, locating the skeptic’s fallacy elsewhere. Third, other contextualists such as David Lewis (‘Elusive Knowledge’, Australasian Journal of Philosophy 74 (1996): 549-67) have not been primarily concerned to combat skepticism and indeed have been quite friendly to it.

14 In discussion at the Oberlin Colloquium.

15 See Williams’ Unnatural Doubts (Princeton University Press, 1996).

16 Thought (Princeton University Press, 1973).

17 This is a major theme of Stroud’s. See also (e.g.) Williams, op.cit.

18 Possible second and third exceptions to the claim that Moore’s argument has hardly been considered are Keith DeRose and Ted A. Warfield’s Introduction to Skepticism: A Contemporary Reader (Oxford University Press, 1999), and Williams, op.cit. These authors see both that Moore’s argument is comparative and that knowledge claims themselves are the operative point of comparison.
       DeRose and Warfield seem to grant that Moore’s argument is tenable; at least they do not explicitly reject it. But they abandon it, as "not very satisfying" (p. 6). Williams actually concedes that Moore has done the skeptic some damage albeit indirectly. But then he seems to miss the point:

To get as far as seeing skepticism as a problem, we must already be susceptible to ideas that block Moore’s response. In particular,…we will see his conviction that there is a hand in front of him…as the conclusion of an inference from his current experiences, and so will want to know how, in the face of such sceptical possibil[i]ties as that Moore may simply be dreaming, those experiences provide the kind of conclusive evidence his certainty demands. Having thus become questionable, Moore’s paradigm knowledge claims can no longer be invoked to rule out the sceptic’s counter-possibilities: Moore’s attempt to confront the sceptic with undeniable examples of knowledge inevitably fails. [p. 43] Well, first, not everyone does get as far as seeing skepticism as a problem, for much the reason Williams gives. Nor does everyone get as far as seeing Moore’s conviction that there is a hand in front of him as the conclusion of an inference from his current experiences: See J.L. Austin, Sense and Sensibilia (Oxford University Press, 1962), and my Judgement and Justification, Cambridge University Press, 1988, Chapter 8.) The cognate version of my interpretation of Moore is that skepticism is simply not a problem.
       But, second and more importantly, even if one grants that skepticism "is a problem," at least in that it takes up space in epistemological anthologies, and even if one did see Moore’s conviction that there is a hand in front of him as the conclusion of an inference from his current experiences, it would still be up to the skeptic to argue that the inference falls short of affording knowledge. And as always, the skeptic’s argument would have suspect philosophical premises. Our knowledge claims may be "questionable" in the same sense in which everything is questionable, but not in the stronger sense that they may actually fall victim to tenable philosophical argument.

19 Moore may have seen a difference:

In the case of the proposition ‘Nobody knows that there are any material things’ it does seem to me more obvious that some further argument is called for, if one is to talk of having proved it to be false, than in the case of ‘There are no material things;’ and this difference is, I think, connected with the fact that an immensely greater number of philosophers have held that nobody knows, than have held that there are none. [‘A Reply to My Critics’, ibid., p. 669.] 20 See, e.g., "What Is Philosophy?," ibid.

21 It is an interesting question whether "common-sense propositions" in this sense are culture-bound. I have tried to restrict the notion so narrowly that all such propositions are entirely transcultural, but I leave the matter open.

22 Thanks to Earl Conee for his illuminating comments produced on short notice, and of course to the Oberlin audience for rich discussion. I am also grateful to Casey Swank and to Andrew Melnyk for helpful comments on a previous draft.

23 In Philosophical Studies (Totowa, NJ: Littlefield, Adams & Co., 1965), p. 228.

24 In Some Main Problems of Philosophy, ibid., p. 143.

25 In Philosophical Papers, ibid., p. 222.