But it may be possible to block this argument before it gets started. That, at least, is what Michael Williams attempts. He challenges the ground rules of the sceptical argument. This he offers the following outline of the dreaming scepticism argument:
if we are to know anything about the world, we must sometimes know that we are not dreaming; but we can never know that we are not dreaming; therefore we never know anything about the world.
The first premiss seems hard to deny. And as for the second, if we are ever to know that we are not dreaming, there must be a test that we can, at least in some circumstances, apply to determine whether we are dreaming or not. But now suppose that there were such a test—any test, not just one conforming to foundationalist preconceptions— it will be of use only if we know that we have really applied it and have not just dreamed that we have applied it. That is, it will be of use only if we already have some way of determining that we are not dreaming, which leads us into a regress... [Williams 1988: 436]
But he goes on to offer the following diagnosis of how the argument works: crucially the hidden premiss which is a form of foundationalism.
We can begin with a look at the first premiss, which can be read two ways. On one reading, it is a truism: at least, something I have no wish to dispute. We can concede that the claim that we sometimes have knowledge of the world logically implies that we sometimes know we are not dreaming. Like other logical points, this is epistemologically neutral. It is entirely compatible with our holding that, since we often do know things about the world, we often know that we are not dreaming: we know that we are not dreaming in virtue of what we know about the world, and in this sense there will be tests for whether or not we are dreaming, though not necessarily any single procedure that applies in all situations.
But there is another way to read the first premiss: this is to take it to require that, if we are to know anything about the world, we must be capable of knowing that we are not dreaming: that is, of knowing this in some way that is independent of all knowledge of the world. On this reading, premiss one certainly promises to be useful to the sceptic, but only because it introduces a general and intrinsic dependence of knowledge of the world on whatever knowledge we can have whether or not we know we are dreaming. So premiss one is either trivial and useless or useful but just another way of insinuating a foundationalist constraint on knowledge of the world. Only by oscillating between the two readings can we sustain the illusion of deducing scepticism from a triviality.
Now, it will be said that scepticism is not meant to follow from premiss one alone, but only from premiss one in conjunction with the claim that there could not be a test, foundationalist or otherwise, for determining whether or not we are dreaming. But unless we read premiss one in the second way, the way that presupposes foundationalism, the argument for premiss two will fail. If the dependence of knowledge of the world on knowledge that we are not dreaming is understood in the first, innocuous way, we have no reason for conceding that there could be no test for determining whether or not we are not dreaming. All the argument for premiss two shows, then, is that there is no way of knowing that one is not dreaming that is independent of all knowledge of the world. But this conclusion poses no threat to knowledge of the world unless it is presupposed that such knowledge, by its very nature, stands in need of grounding in some more primitive stratum of knowledge. The argument for premiss two shows that there can be no purely experiential test for determining whether or not we are dreaming, and the epistemological significance of this conclusion derives entirely from the thought that knowledge of the world naturally requires some kind of grounding in experience. Once again, the dreaming argument shows that foundationalist ambitions are likely to be disappointed, but gives no independent reason for entertaining them in the first place. [Williams 1988: 437 italics added]
Elsewhere he summarises this move in in slightly different language:
In effect, what the argument for [scepticism] ... really shows is that there is no way of knowing that we are not dreaming that is independent of all knowledge of the world: there is no purely experiential test by which to exclude the dream possibility. But this conclusion poses no threat to knowledge of the world unless we have already been given reason to think that such knowledge, by its very nature, always requires grounding in some more primitive stratum of knowledge. The argument for there being no test for determining whether or not we are dreaming turns out to be another way of making the point that knowledge of the world cannot be given a ground in experiential knowledge, which is not a step on the road to scepticism unless it has been established that knowledge of the world stands or falls with the possibility of giving it such a grounding. Once again we have an argument that shows that foundationalist ambitions are likely to be disappointed, but gives no particular reason for entertaining them in the first place. [Williams 1996: 87]
So Williams aims to show that the argument for dreaming scepticism can be blocked by showing that it depends on an 'unnatural' assumption that knowledge of the world depends on a substratum of knowledge of experience. Only if the latter can be used to show that there is no general problem with the former are we justified in our everyday beliefs and that is just what scepticism goes on to question (via ringers such as dreaming and the brain in the vat). But Williams argues that that is just an assumption. If it leads to scepticism then so much the worse for that assumption.
He calls the assumption that drives the sceptical argument ‘epistemological realism’. It is the idea that knowledge of the world is a natural kind, a uniform totality, which can be questioned or justified as a whole. That idea is certainly present in Descartes' discussion but it seems, there, to be merely a convenient way of doing the sceptical job quickly. Williams thinks it is more significant than that and actually underpins the sceptical argument.
Does this work?
Williams aims at a theoretical diagnosis of the sceptical argument. He claims that the sceptical argument depends on what seemed merely an accidental feature of Descartes’ method of doubt: treating our knowledge of the external world as a single type of knowledge, sharing a common style of justification (via (our knowledge of) our experience). But the idea that there is such a class as ‘our knowledge of the external world’ is not a natural idea and this category is theoretical and artificial. So once we realise that the sceptic relies on this assumption – for example in the way normal ways of justifying our claim that we are not now dreaming are ruled out because we need to prove we are not dreaming independently of anything else we know about the world – it is equally possible to reject both it and the scepticism it leads to. Further, the very fact it leads to scepticism (which is obvious rubbish) counts against it.
Williams also provides some further comments to try to persuade us that as ‘our knowledge of the external world’ is not a natural idea. His comment that Descartes’ claim that our bodies are external seems spot on.
Is this enough to stop scepticism? Unlike Putnam, he does not claim that the sceptical hypothesis makes no sense. So he does not say that scepticism makes no sense. That may count in his favour (since scepticism seems to make sense). But, unlike Davidson, he does not let the sceptical argument go through. Once it does it seems merely dogmatic to attempt to deny it. Instead, Williams aims to show that scepticism depends on a theoretical view of knowledge which is neither obligatory nor natural.
Still, one might think that the sceptical possibility is the most natural aspect, not of everyday life but certainly, of philosophical inquiry. That is, as soon as one begins to think about knowledge, one realises that there is a central tension in what we take it to be and in our taking ourselves to have it. So in the end, Williams may trade intuitions about what is and is not natural.
If that is how things stack up then one way one might aim to break the deadlock is by considering the plausibility of what Williams opposes to epistemological realism (the view that our knowledge of the external world as a single type of knowledge sharing a common style of justification). What is the alternative? Contextualism.
Epistemological realism takes it that good justifications have a common feature: they start with our experience construed as not presupposing any knowledge of the external world and then work outwards to the external world. What does contextualism take all good justifications to have in common? Nothing (well, nothing substantial). Justification depends on, and varies with, context.
It would be good to learn more of what this involves (see Wittgenstein later). But if contextualism is a better account than epistemological realism (before we consider scepticism) then since scepticism needs a prior assumption of realism, that really would count against scepticism.
“But hang on. If there are two views of knowledge and justification in play: epistemological realism and contextualism (where the former leads to scepticism), then isn't the idea that this blocks scepticism merely dogmatism at one level up. At the ground level, sceptical hypotheses or ringers don't have to be true, they just have to be possible. Their mere undetectable possibility is enough to undermine knowledge - because even if our beliefs about the external world that is mere luck in the face of the ringers - and thus lead to scepticism. So equally at this higher level of abstraction (concerning knowledge of the nature of knowledge rather than trees etc), epistemological realism doesn't have to be true, it just has to be possible, for that fact to undermine, via the standard sceptical argument, ground level knowledge and thus lead to scepticism.”
I don't think so. After the sceptical argument is already up and running, then the fact that we have a stand-off between epistemological realism and contextualism might be enough to hand the victory to scepticism. (First, if we have already granted that we don't know that that! is a tree, then we will not likely know the nature of knowledge either and then, second, if we do not know that contextualism is true then we won't know that that! is a tree: a kind of mutually supportive sceptical collapse.) But Williams contests the argument before the sceptical argument is complete for the first time.
So the stand off between epistemological realism and contextualism is more neutral. It is played out on ordinary pre-sceptical grounds. Only if we have reason to think that epistemological realism is reasonable can the way the sceptic sets up his ringers be reasonable and thus, for the first time, make us concede that we don't have knowledge. But if our response to the sceptic's initial claim - that our knowledge of the world depends on a more certain knowledge of experience - was that that was an absurd idea (because, eg. I only learn to talk about my experiences long after I learn to talk about trees etc), then we would never have been worried about scepticism in the first place. Nothing would follow from the mere existence of sceptical ringers.
Williams, M. (1988) 'Epistemological realism and the basis of scepticism' Mind 97
Williams, M. (1996) Unnatural doubts, Oxford: Blackwell
