I want you to tell me what's real.

I want to ask a question, and I do want to know what you think.  Please comment.

What is real?  And, if you're feeling extra ambitious, what is required to prove to you that something is real?

I realize that this is a rather ethereal question, but I think having an answer--or at least recognizing it as a question to be worked out--is pretty important.  Today's common unconscious answer seems to be anything which is or can be proven by science.  Since most of us are not scientists, this sort of answer -- Never mind.  I want to hear your thoughts in the comment thread.