Great Puzzle

How queer everything is to-day!  And yesterday things went on just as usual.  I wonder if I've been changed in the night?  Let me think: was I the same when I got up this morning?  I almost think I can remember feeling a little different.  But if I'm not the same, the next question is, "Who in the world am I?"  Ah, that's the great puzzle!

-- Charles Lutwidge Dodgson (1832 - 1898), British author and mathematician, writing as Lewis Carroll, Alice in Wonderland (1865), chapter 2; reprinted in Logical Nonsense: The Works of Lewis Carroll (1934), p. 177