Linda is a young, outspoken philosophy major who is deeply involved in social justice movements and anti-nuclear protests. Is it more likely that (a) she is a bank teller, or (b) that she is a bank ...

"Yes or no: was there once life on Mars?" I can't say. "What about intelligent life?"' That seems most unlikely, but again, I can't really say. The simple yes-or-no framework has no place for shadings ...