Friday, March 30, 2012

How (not) to reply to the skeptic

External World Skepticism is the view that we do not have knowledge about the world around us. In reply to this view, some have argued that we should reject the sorts of skeptical challenges (e.g., that we might currently be dreaming, that we might be in the Matrix, etc.) that the skeptic suggests undermines our having knowledge. A principle like the following might be invoked:

Given a conflict between two beliefs, it is rational to reject the less initially plausible one, rather than the more plausible one.

The anti-skeptic can thus argue that my belief that there's a keyboard before me is more plausible than that my belief that I might be merely dreaming the keyboard. As a result, it's rational for me to reject the skeptical scenario (that I'm dreaming) and accept the more plausible explanation of my perceptions (that there's really a keyboard before me).

Michael Huemer suggests that this is G.E. Moore's strategy in replying to the skeptic.

I wonder what readers of this blog think of the principle above. I'm especially interested in the clause 'initial plausibility.' What, for example, entitles one to claim that my belief about there actually is a keyboard before me has more initial plausibility than my beliefs that knowledge requires the ability to rule out skeptical scenarios like that I'm dreaming or that I might be dreaming right now or that this keyboard that I seem to see might be a hallucination?


Anonymous said...

Well, wouldn't the skeptic simply agree that it might be more reasonable or rational to believe that I'm not dreaming - that there is a greater probability that I am awake and not dreaming; yet assert that I do not KNOW that I am not dreaming since knowing entails that the thing I purportedly KNOW must be TRUE? If I do not KNOW that I am not dreaming, then I do not KNOW that the keyboard is in front of me.

Jesse Steinberg said...

I think the idea is that since it's more rational/reasonable for me to believe that there's a keyboard before me, and since this belief entails that I'm not merely dreaming, then the skeptical hypothesis does not really pose a challenge to my having knowledge.

The argument is something like:
(1) If I don't know that I'm not dreaming, then I don't know that there's a keyboard before me.
(2) I do know that there's a keyboard before me.
(3) But then I can conclude that I know that I'm not dreaming.

Of course, as you suggest, the skeptic will challenge (2). All we've esablished (if that!) is that it's rational to believe that there's a keyboard before me. Anyway, this is the argument as Huemer sees it.

What I'm worried about is the first step. Is it really more rational/reasonable to believe that there's a keyboard before me? Why not think it's equally reasonable to believe that I'm dreaming right now? So my question is about rationality/reasonability more than about the anti-skeptical argument.

In the end, I think you're right that Moore's maneuver will not work.

Anonymous said...

Well, I tend to think that it really IS 'reasonable" to believe that I am not now dreaming and also 'reasonable' to believe that there is a keyboard in front of me.

If you think about the legal standard of "what a reasonable man would believe", then I think judges would find these examples to fit the standard of what a reasonable man would believe. If I went to court and claimed that I didn't act to save a man lying in the gutter with his face in water by simply turning him over, would I be able to claim that I didn't act because I didn't believe that I was awake or that I didn't believe there was really a man in front of me in the gutter?

That being said, what this shows is that whether it is reasonable to believe something is one issue; and whether, from the fact that it might be reasonable to believe something, I can then conclude that what I believe is true. As Plato said, knowledge is true (justified) belief. One might say that my belief is justified and still deny that it is knowledge as my belief may not be true.

What do you think?

Jesse Steinberg said...

Just to be clear, I don't mean by "first step" the first premise of the argument in this comment thread. I mean the issue of whether we ought to accept the bit of text in bold in my post: "Given a conflict between two beliefs, it is rational to reject the less initially plausible one..."

Anonymous said...

When a magician makes an object seem to disappear, in vain does he convince us of his power over objects by repeating the trick because no magician has ever annhiliated an object. It is only in a dream or hallucinatory state we call into question our mental faculties as when we dream of a deceased loved one and proclaim: "I am dreaming". The appeal is to induction, which operates on us sensibly rather than cognitively save the lone principle: that something cannot both be and not be.

To call into question or doubt the keyboard in front of you is, as Hume puts it, to 'argue without an antagonist' as this requires a sensible, rather than cognitive, appeal to experience with keyboards that are not really there. The existence of the keyboard is probable in a cognitive sense - we could be dreaming; but only past experience of keyboards that are really not there could ever provide us with any sensible doubt.