Topics Knowledge

Question it seems that an entire 'philosophical system' (for lack of a better phrase) is built around the epistemological idea that I cannot escape my own consciousness (i.e. the argument from illusion). It is sometimes difficult for me, however, to take seriously the suggestion that I cannot prove that I'm not dreaming. I feel that I know that Descartes is quite right (I could be dreaming and I cannot PROVE that I'm not). However, on some very very important level, I do know that, in fact, I'm not dreaming even given the argument from illusion. Therefore, it's quite difficult for me to take the suggestion seriously. Could I be taking this all too seriously or considering it of much more import than is necessary?

Accepted:
March 12, 2009

Comments

It's worth saying something first about Descartes (as it wasn't his view that he couldn't prove he wasn't dreaming).

Descartes is troubled that, as he sees it, the then dominant systematic story of the world is in deep error, and is getting in the way of the growth of the revolutionary new science of the day. He has a diagnosis, too, of the source of error -- he sees Aristotelianism as springing from some deeply embedded childhood habits of thought. Radical measures are required to prise us out of such deep-rooted error. The ‘Method of Doubt’ provides the once-in-a-lifetime jolt needed to shift us out of certain childish thought-habits and to get us adopt better intellectual methods and open the way to improved science. Faced with even the most reasonable-seeming presumptions, Descartes suggests, "I must withhold my assent from these former beliefs just as carefully as I would from obvious falsehoods, if I want to discover any certainty in the sciences." So for Descartes, it is not that our former beliefs are all unreasonable: but rather we are to play along with fantasies about dreams and evil demons as an instrumental step to help us sort out the safe beliefs from the contaminated dross.

Descartes’s hope and belief is that, after a temporary strategic retreat from received views and common sense, he will still be left with enough indubitable foundational beliefs to provide a secure bridgehead from which he can ﬁght back and recover those common-sense beliefs that don’t carry the baggage of disputable theory -- including of course his common-sense belief that he is sitting by the fire, wide awake. And he can then go on to ground a secure corpuscularian science.

Of course , notoriously, Descartes's fightback is problematic in all kinds of ways. But he certainly thought he could establish on firm grounds the general reliability of the senses and the security of our ordinary knowledge that we are not dreaming.

But that's history, you might say. Descartes might have raised the thought that he might be dreaming just as a methodological tool rather than as a hypothesis about how things really might be to be seriously entertained. But now the doubt has entered in, it (as it were) takes on a life of its own: so how do I prove I'm not dreaming?

Well, speaking for myself, I’m all for a cheerfully resolute response. We have every good reason to suppose that in ordinary life, when our usual criteria indicate that we are wide awake and not dreaming, we are wide awake and not dreaming. And what if the sceptic asks me how I rule out the possibility that, for all that, my whole ordinary ‘waking’ life is in fact just one big coherent dream (unlike any ordinary dream, of course, perhaps being a put-up job engineered by an evil demon)? I just riposte that I have been given not the slightest reason that to suppose that that is a live possibility. As the questioner puts it, it is difficult for me to take the suggestion seriously. Why should I? It is one thing to use the evil demon fantasy as Descartes does, as an imaginative tool in trying to locate some core of infallible beliefs: it is something else entirely to imagine that the honest enquirer needs to rule out the evil demon scenario before he can regard science (broadly conceived) as a reasonable enterprise. The scientist just doesn’t have to waste her time ruling out myriads of daft hypotheses she hasn’t the slightest reason to suppose are true. And for me, that’s pretty much the end of the story.

Of course, in saying that, I'm just relying on our familiar beliefs and best scientific methods for proceeding. But what else am I supposed to do? True, I can’t justify anything without appeal to such familiar beliefs and best scientific methods. But so what? Well, some say (in fact this is a quotation from Barry Stroud),

. . in philosophy we want to understand how any knowledge of an independent world is gained on any of the occasions on which knowledge of the world is gained through sense-perception. So, unlike . . . everyday cases, when we understand the particular case in the way we must understand it for philosophical purposes, we cannot appeal to some piece of knowledge we think we have already got about an independent world.

But what notion of ‘philosophy’ is in play here? I for one just haven’t much grip on what sort of coherent project there could be here, this special ‘philosophical’ enquiry that isn’t part of science broadly conceived. Again quoting Stroud, it seems that

All of my knowledge of the external world is supposed to have been brought into question in one fell swoop . . . I am to focus on my relation to the whole body of beliefs which I take to be knowledge of the external world and to ask, from ‘outside’ as it were . . . whether and how I know it . . .

But that gives the game away. If the ‘philosophical’ project is supposed to involve jumping outside my beliefs and methods, and trying to squint sideways at them from ‘outside’ as it were, to try to justify them as matching up to an external world, then that is just incoherent. If the sceptic is complaining that that project of justifying can’t be pulled oﬀ, then he’s quite right the project is impossible, but quite wrong to complain. You can’t be both ‘inside’ and ‘outside’ your own thoughts (thinking them, but squinting at them sideways too).