Aye, a dirty trick, but such are the meat of magicians it seems. It's a rather hard thing to describe and define, I think having definitions that work on multiple levels and open up as your understanding opens up is the best we can do.

"Magic uses some sort of non-physical forces or forces to cause change."

Right, but is thought physical? Meaning? Whether or not we posit or experience levels above thought and meaning, we are already in murky waters.