Could we ever know? :) I was just talking to b_b yesterday about how philosophy lags decades behind what physics has revealed, by asking questions that we know are flawed from the outset. Heck many physicists lag decades behind physics, in fact. Beyond out own gut instinct, there doesn't seem to be any evidence that we exist as a unit in any sense of the word. Not only are we smeared about space, but we are smeared about time. Like everything else, we are a cloud of possibilities, defined only by that which we interact with. To the extent that you want a cheeseburger, only those that can verify that you've eaten one, have a compelling answer, I think. :) Although I agree that it might be disconcerting, it is also highly supportive of the notion that you can change yourself by changing your environment.I think I want a cheeseburger. But do I really want a cheeseburger?