On page 4 or so. . . I can't let this one go, sorry. In your "pie" problem, what about negative numbers? Pieces one already ate? What physical correspondence is there? I have yet to understand people's objections to complex numbers (including my husband's.) A complex number makes sense: you multiply it to another complex number to get a real number, you multiply a negative number to another negative number to get a positive number. You just can't add them to get a real number. I think it's just the names that get to people. Mathematics comes from the world around us; that's how we got it. Complex numbers wouldn't have been formulated if we didn't need them. (This is also why I'm dismayed when others are surprised about the applicability of an obscure branch of mathematics to some physical system. It has to apply to *something*. . .) Anyway, I guess my point is, why would Psi need to be anything more than a "probability density"? Does the square root of any other physical quantity have to have a separate physical meaning? As far as I have read, Psi contains what we can speak about. That's a tall order in and of itself. As for the rest of the discussion: I agree it would be *nice* to have some clasically-compatible interpretations for these things, but does the universe require it? Must the universe behave according to our ability to create analogies? I don't think so. I am pro "let's play with the math and see what we can find", but let the experiments and the math do the actual talking. :-X To ZapperZ; if this is too naive, let me know and I'll shut my mouth. In fact, I think I'll save ZapperZ the time and shut it now.