Am I Just a Brain in a Vat?
The stuff of college-dorm bull sessions includes questions like: How do I know I'm not just a brain in a vat in some lab? or How do I know the world didn't begin the day I was born? or How do I know that other people aren't really robots? or Could "The Matrix" be true? Contemplating these things can be fun, especially when under the influence of certain chemicals. But don't take them too seriously. Why not? Beyond the fun, such questions can be meant to raise doubts about fundamental beliefs regarding the world we experience every day and see no need to question. The one sowing the doubts feels that he has the advantage: he throws down a challenge, thinking he has put his listeners on the spot. Well, let's see you prove you're not just a brain in a vat! But the doubter, or skeptic, bears a responsibility that he can't escape so easily. As Ludwig Wittgenstein wrote in On Certainty , "What we can ask is whether it can make sense t