Inertia, Optimism and Beauty

The best arguments for the 1/3 answer to the Sleeping Beauty problem all require that when Beauty awakes on Monday she should be uncertain what day it is. I argue that this claim should be rejected, thereby clearing the way to accept the 1/2 solution. 1 Inertia and Sleeping Beauty If on Monday you confidently and rationally believe that Slippery Slim is guilty, and from Monday to Tuesday you gain no new relevant evidence, then, quite plausibly, on Tuesday you should remain equally confident that Slippery Slim is guilty. Lots of evidence might be relevant: that Slim has an impeccable alibi, that the informant who fingered Slim is unreliable, that Mournful Mel has confessed to the crime, that your biases have clouded your judgment, and so on. But if you learn nothing at all relevant to your confident belief that Slim is guilty, then surely you should remain confident that Slim is guilty. Perhaps that was too quick. Suppose you lose some relevant evidence— say you forget why you became convinced that Slim is guilty— then perhaps you should become less confident that he is guilty. Or maybe your confidence should change if your