The radical sceptical hypothesis cited in the question above has been a source of epistemic frustration since the time of Plato, and has gripped philosophical interest through Sextus Empiricus, Michel de Montaign, up to Descartes whose Method of Doubt employs the most famous formulation of the Dreaming Argument, which goes from an unexceptional premise to the extraordinary conclusion that we have no knowledge at all. The claim in question seems insuperable from a philosophical sceptical standpoint; notwithstanding, there have been serious attempts to refute the sceptic, each with varying degrees of success.
However, it seems that almost every attempt at dodging the bogey of scepticism has, by the highest epistemic standards, failed. In this essay, I will consider the arguments that have been raised to meet the sceptic head on, and discuss their strengths and limitations. The sceptic’s argument suggests that anything possible to experience in one’s waking life is also possible to experience as a dream, as we can have experiences that are indistinguishable from waking whilst fast asleep.
The premise (D), “It is impossible to tell whether one is dreaming” in conjunction with the traditional tripartite analysis of knowledge would render any knowledge impossible. According to the sceptic, if you cannot be certain that (D) does not obtain, you cannot possess justification for any of your beliefs. For example, a proposition such as, “I am at my desk writing this essay”, is not justified, since the possibility that I am not in fact asleep and dreaming cannot be eliminated.
The dreaming argument can be better analysed when it is broken down into its constituent premises and conclusions: 1. ) I have had dreams which were experientially indistinguishable from waking experiences. 2. ) So the qualitative character of my experience does not guarantee that I am now not dreaming, then I can’t know that I’m now not dreaming. 3. ) If the qualitative character of my experience does not guarantee that I’m now not dreaming, then I can’t know that I’m now not dreaming.
4. ) So, from 2 and 3, I can’t know that I’m now not dreaming. 5. ) If I can’t know that I’m now not dreaming, then I can’t know that I’m not always dreaming. 6. ) So, from 4 and 5, I can’t know that I’m not always dreaming. 7. ) If I can’t know that I’m not always dreaming, then I can’t know to be true any belief about the external world which is based on my experience. 8. ) So, from 6 and 7, I can’t know to be true any belief about the external world which is based on my experience.
The first and most obvious point of contention is the truth of premise 1: that dreams are experientially indistinguishable from waking experiences. J. L. Austin denies the truth of this premise, arguing that since we have the expression, “a dream-like quality” there must be a special quality that dreaming experiences possess which waking experiences lack, if the expression is to possess meaningfulness. The only explanation for this description and differentiation between waking and dreaming states is that the qualitative character of dreams is different from that of waking experiences.
However, the sceptic can reply to this claim by establishing that there are two kinds of dreams, those which are hazy and obscure, possessing the so-called “dream-like quality” and those that are vivid and pellucid; it is this second kind of dream that is being adduced in the sceptic’s radical hypothesis, thus the sceptic deflects the knower’s refutation. However, G. E. Moore is also keen to deny the sceptic his first premise. Moore’s argument states that in the mere offering of the sceptical argument, the sceptic is implicitly committing himself to know that the premises are true.
Henceforth, if the argument is valid, then by its own conclusion, the sceptic would not be in a position to know anything about how dreams compared to waking experiences. So, the sceptic’s argument is self-defeating: if the conclusion were true, the sceptic wouldn’t be in a position to know the argument’s premises. The sceptic is also guilty of his own dogmatism here by assuming his premises to be true. However, the sceptic is able to reply by softening his first premise: he doesn’t need premise 1 to be true, it merely needs to be possible of being true.
However, he must now adopt a different criterion for knowledge if he is to move away from perceptual evidence as a mark of veridicality, to a priori reasoning about the concept of dreaming – the argument from dreaming is imaginatively intelligible. Moore also denies the sceptic his conclusion: that there is no way of knowing anything about an external world, or that there even exists an external world. Moore’s attempt places the onus of proof on the sceptic, but is fraught with problems: his attempt to refute scepticism is dogmatic, question-begging and circular in nature.
His ‘Proof of an External World’ consists in him his raising one hand, and then another, and twisting them about before himself, which leads him to the conclusion that there is an external world. This is really an appeal to common sense where his argument goes: Premise: Here is one hand and here is another. First conclusion: Two hands exist at the moment. Second conclusion: At least two external objects exist at the moment. Moore’s argument only succeeds in that it is ultimately more plausible than the sceptic’s. Moore’s argument employs modus ponens, the “mood that affirms”: P therefore Q – P is true, therefore Q is true.
In Moore’s argument this translates as, “This is a hand, therefore there is an external world. ” The sceptic, however, turns the argument around and employs the “mood than denies,” modus tollens, where: P therefore Q – Q is false, therefore P is false. In this case, “There is no external world, therefore there is not a hand. ” Unequivocally, the sceptic makes a considerably more difficult, theoretical claim than Moore, thus it can be contended that Moore’s argument has more to commend it than the sceptic’s, and therefore Moore’s proof succeeds tentatively, despite its logically fallacious appeal to common sense.
However, while this appears a victory to Moore and the anti-sceptical brigade, Moore’s argument is guilty of a number of fallacies that threatens his claim to knowledge of the external world, and even to the knowledge he has of his hands before him. Notwithstanding, if Moore’s conclusion is true that there is an external world, then we can deny the truth of the conclusion in the sceptic’s dreaming argument, so that the threat of global scepticism goes away. If we know we can have knowledge of the external world, this necessarily means the premise does not entail the conclusion and the argument is invalid.
Moore’s proof, however, lies on very shaky grounds, and he commits several unacceptable logical fallacies, taking for granted the reliability of his sense faculties – a problem that has thwarted two millennia of philosophers – but not Moore. When asked how Moore knows his premise, “Here is a hand”, he simply reiterates the statement, offering it as evidence for itself. This is, to use Santayana’s term, a “gratuitious dogma”. This refers both to Moore’s ontological and epistemological argument: he takes it as a given that objects exist, and that we can know of them – dogmas which became a focus for Kant during the Enlightenment.
By the same token, Moore begs the question: in asking how we have knowledge of this or that, you cannot simply answer the question by asserting the truth of this or that. Barry Stroud finds this a particular failing of Moore: he has failed to adopt a detached position that Stroud believes is required in order to refute philosophical scepticism. On Stroud’s view, Moore is not entitled to appeal to what he knows about external things because all such knowledge has been called into question.
However, there is a condition where Moore could be said to be in the possession of knowledge: where knowledge (as true justified belief) derives from a reliable method, and when we adopt a strong cognitive externalist standpoint. Henceforth, if our senses are reliable means of tracking the truth, from an externalist view, we can be said to have knowledge. As with the quoted radical sceptical hypothesis, there is a real problem with what marks experience as being veridical experience – how we interact with the external world (presuming it exists), if indeed we have any access to it at all.
This problem was one that interested Bertrand Russell who sought characteristics in our own purely private experiences that “tend to show that there are in the world things other than ourselves and our private experiences. ” The problem for Russell, and for Descartes, is that although something looks a certain way, it does not necessarily entail that it is that way, since we cannot find within the appearances a criterion for distinguishing dreams from reality. This is known as the problem of “shaky inference” that resists the move from how things appear to be, to how things really are.
This is the problem with the theory of perception known as Indirect Realism, where we are committed to believing that there exists an external world independent of our experience of it, but that we can get to know the world ‘indirectly’ through experience. The problem with Indirect Realism is that by making our perceptual knowledge of the world inferential, it threatens to dislocate us from the world altogether. This view is slightly more plausible than its counterpart, Direct Realism, which states that we should take our perceptual experiences at face value, and that they lead to knowledge of the external world.
Clearly the Argument from Illusion makes Direct Realism indefensible, as it offers no justification for non-veridical experiences. A view that replaces and, I would argue, improves upon these unsatisfactory theories of perception are Idealist theories, which traditionally views that, independent of our experience of it, there can be no knowledge of an external world. In this vein, it is extremely difficult to refute the sceptic, both Berkeley and Russell believe the idea of inferring material objects from our internal experiences is hopeless and impossible, and therefore they contemplate a solipsistic position.
Russell considers the sceptic’s dreaming argument to be a logical possibility, and even entertains that his whole life had been a dream. However, Russell concedes that our belief system, on the whole, is simpler, and more coherent if we accept our instinctive belief in the external world. However, in doing so, Russell essentially sidesteps the sceptic’s argument, acquiescing to a position of dogmatism, positing the external world’s existence to give order to the chaos of the sceptical downward spiral.
Thus far, we have no method that succeeds in defeating the sceptic’s argument. There is almost no consensus about how we can access the external world, if it exists at all, so whether we are dreaming or not is immaterial if we can never get beyond the wall of our perceptual apparatus, never able to know things-in-themselves, or noumena in Kant’s words; all we ever ‘know’ are how things appear to us, what Kant termed ‘Transcendental Idealism’.
Kant still maintains, however, that we can know that external world exists through rational reflection, but nonetheless gives us ample reason for favouring the sceptic’s position. However, there is still a possibility of challenging and overturning the sceptic’s decree, in quite convincing fashion. Robert Nozick’s defence of the possibility of knowledge draws upon the ‘Principle of Closure under Known Entailment,’ which can be proven to fail in certain contexts.
According to the principle, if S knows that P, and P entails Q, then S also knows that Q – since P must be true, and a true antecedent cannot entail a false consequent. Therefore, if I know that P, “I am sitting at my desk writing this essay”, this entails Q, “I am not at home dreaming that I am writing an essay at my desk. ” However, the sceptic employs modus tollens and says I don’t know that Q, so I don’t know P either. But Nozick replies by analyzing the alternative possibilities in terms of “possible worlds”.
For instance, in the possible world nearest to the actual one, if I am not sitting here at my desk writing this essay, I may be sitting in the garden with a cup of tea, feeding my cat, or awaiting the delivery of a parcel. A vivid dream that follows consistently for such a long period as I have been sat here writing this essay, while indeed a logical possibility, is unlikely enough not be the case in the reasonably ‘nearby’ worlds, and therefore, according to Nozick, the Principle of Closure under Known Entailment fails when considering radical sceptical hypotheses.
However, Nozick’s argument was formulated against the Brain in a Vat scenario, which seems to have much less chance of obtaining in actuality than the dreaming argument. Hence, Nozick’s response can be said to fit both examples of the hyperbolic sceptical argument. Our focus now turns to the premise of the argument in question: “There is no way of telling whether you are dreaming. ” If it is possible to deny the truth of this premise, the argument becomes invalidated, and the threat of global scepticism is diminished.
The first possibility is to move from an infallibilist model of knowledge to a fallibilist model of knowledge. The premise of the question seems to rely on the Certainty Principle: “If you know that P, then you must have indefeasible, absolutely certain evidence for P. ” When we reject the infallibilist model of knowledge, we can claim to know that P on the basis of defeasible evidence: we can know that P, even if our evidence is fallible.
Naturally, the sceptic finds this unacceptable, since the anti-sceptic is essentially just moving the goalposts. It is epistemically irresponsible to lower the threshold for knowledge – the purpose of scepticism is to find indubitable truths: lowering the boundaries for knowledge is a form of Contextualism that clearly sidesteps rather than confronts the argument at issue. Of course we want to say we can have knowledge of this or that, but the route taken by the anti-sceptic to achieve this seems, almost with exception, to lead to dogmatism.
Attempts at defeating scepticism have proved unsuccessful, or at least unconvincing, throughout the history of philosophy. Descartes’ appeal to clear and distinct ideas as a source of a priori indubitable knowledge is circular and unacceptable, Moore’s appeal to common sense is dogmatic and question-begging, Russell gives up the fight and continues living with animalistic blind faith, and shifting the goalposts, as recommended by fallibilism and contextualism, circumvents the very point of philosophical scepticism.
Our perceptual experiences offer no true mark of veridicality, unless you accept the realist position of ‘seeing is believing’, or capitulate to Lehrer’s assumption that our senses are ultimately trustworthy – whether we are dreaming or not, if in waking we still are unconnected from the external world, it does suggest that the non-existence of the external world is a logical possibility, despite how it arouses in us a sense of indignant incredulity.
Perhaps we are all there is, to yield to the solipsistic argument – perhaps our minds merely invent the objects of perception we take to exist; if there is no guaranteed method of accessing the external world and its contents, solipsism is not remotely absurd nor illogical. However, I do believe there is a way of telling whether or not you are dreaming, even if some dreams do not possess the trademark “dream-like state” cited by Austin.
Dreams have a particular phenomenological quality – a quality that, although I cannot speak on behalf of anybody else or claim to know the contents of others’ minds, I can remark on, reflect on, and label as my experience of dreaming, D. Therefore, I do not consider the dreaming argument to be sceptically dangerous. Dreams are episodic, hazy, and stand removed from the continuous narrative of my life; I deny that dreams ever possess the particular phenomenological quality that I know to be my waking experiences, W.
Although both are products of my living experience, D and W do not overlap on any conceivable Venn diagram. I have privileged access to my own thoughts and the quality of my own internal experience, and as such I wish to say this knowledge is self-evident to me. Whether there is an external world that my perceptual faculties interact with (or would seem to do) is a more difficult question: all I know is that I am capable of experiencing certain characteristic phenomenological experiences.
This could lead to a position of solipsism where I am all there is, although the ‘I’ in question is potentially still unknowable, or we can look to Kant’s Transcendental Idealism that denies the possibility of knowing ‘things in themselves’, but through some rational process we can know an external world exists. Berkeley’s misgivings chime in with my own here, “it is possible we might be affected with all the ideas we have now, although no bodies existed without resembling them.
” Conceivably, my entire life may have been a dream – potentially what I label as D and W are in fact both experiential states found in a foreign ‘dreaming’ state that I am not aware of. Plainly, when knowledge of my perceptual faculties has been called into doubt, I am not justified in appealing to yet more perceptual experience for justification – that would be circular and so the sceptic prevails.
However, this sceptical scenario is at odds with the fact that I am using language to think (and dream) in, thus I must have (or, at least, have had) interaction with other conscious agents in order to correctly utilize a rules-based, essentially social system such as language. If dreaming is conceived to be a solo activity, the fact that I possess language, which only arises in contexts where there exist other linguists, rules out the possibility that my life has been an extended dream.
According to Wittgenstein’s Private Language Argument, it is impossible to acquire a language that follows systematic rules if it is private, belonging only to its thinker. The argument follows that a solitary would-be language-user be unable to tell the difference between actually following the rules and merely believing that he is doing so; so the language he speaks cannot be logically private to himself.
It must be shared – and can indeed only be acquired, in the first place in a public setting, in an external world. Thus it seems the sceptic is victorious with his radical hypothesis, as he is unwilling (and justifiably so) to agree to standards of knowledge that are less than absolute.
As far as challenges go, however, Nozick’s attempt seems to offer the most disabling response to scepticism, through the postulation of other possible worlds, meanwhile the aforementioned phenomenological argument shows that the sceptic’s argument may not have universal application, so that if the conclusion is false and there is an external world (although only certain individuals will be in a privileged position for internalist verification), it must entail that the external world exists for everybody, irrespective of their awareness of it.
However, the sceptic raises the stakes and still contests that we cannot rule out alternative possibilities that our entire lives may consist of a prolonged coma, where there is no waking experience at all, thus granting justification to his hyperbolic argument. Perhaps it reveals my own hedging dogmatism, but I wish to say that it is inconclusive whether we can really know whether or not we are dreaming, as we lack a mark of reliability within ourselves that is neither circular nor dogmatic; adopting a position of Pyrrhonian scepticism would seem extreme, but the justification to do otherwise rests on extremely shaky terrain.
Thus, the premise of the sceptic’s argument holds, and as such, a true antecedent necessarily entails a true consequent, and we are prevented for asserting knowledge of an external world. Appeals to common sense and asserting the reliability of our sense faculties merely sidesteps, rather than addresses, the sceptical hypothesis; scepticism rightly places the bar for knowledge as high as certainty, and any attempt to lower that threshold is guilty of circumventing the problem, rather than dissolving it. Bibliography: Duncan Pritchard, 2010. What is this thing called knowledge? Routledge.
David Blumenfeld and Jean Blumenfeld, 1978. ‘Can I know that I am not dreaming? ’ Descartes: Critical and interpretative essays. Baltimore. Barry Stroud, 1985. The Significance of Philosophical Scepticism. Oxford University Press. Charles Landesman, 2002. Skepticism: The Central Issues. Blackwell Publishing. Stanford Encyclopedia of Philosophy. “Skepticism”. Jonathan Dancy, 1985. Introduction to Contemporary Epistemology. Blackwell Publishing. ——————————————– [ 1 ]. I personally reject this premise, as I have had no such experiences and therefore am in no position to argue its validity.
The sceptic’s argument maybe only applies on a case by case basis; the sceptic assumes we know what he is talking about, when we may have had no such experiences. [ 2 ]. From David and Jean Blumenfeld, 1978. “Can I Know That I Am Not Dreaming? ” [ 3 ]. This is true if you accept the Cartesian sceptical project. Scepticism is not just a hobby for the bloody-minded: at its core is the search for something “stable and likely to last,” after all, we do want to say we have knowledge – it is valuable to human life. [ 4 ]. Perhaps something like an extended coma experienced since birth. [ 5 ]. A. C. Grayling, “Scepticism and Justification”.