Huh? How would we get through life if if we didn't assume we existed? What is "existed" anyway?

I *knew* that would cause complications. I could have just said "Not only do we behave as if we knew more than we do, it's essential to do so to survive" but someone would have picked up that that contains assumptions about existance.

An example: we drive as if we knew how the other bloke will behave, but we don't really know that. On the other hand, we couldn't drive without crashing unless we made some assumptions about what everyone else will do.