Abstract

This lecture will last less than twenty four hours. I know that, and so do you. And you knew it before I said so. How? Because you knew that lectures don't last twenty four hours. How do you know that? You haven't heard this one, and 'for all you know' (as the saying is) I could go on all night. But you know I won't. And the 'all you know' which tells you that, without entailing it, is the fact that none, or almost none, of the many lectures, on all subjects, which you've heard or heard of, have lasted that long. If many of them had, you wouldn't have known that this one won't; but as it is, you do know that.