Same with gravity. It's not a scientific "fact" that gravity is gravity. It's just a placeholder for now. I could go on and on, but I am going to assume too many feeble minds will try to argue.

I recommend this book to anyone who comes into this thread (free pdf DL): http://www.google.com/url?sa=t&sourc...S5quhjOcBoq_kQ

I also recommend the movie "Proof": http://www.youtube.com/watch?v=DI1vRch4omw

And if you do watch the movie, pay attention to the last line in the movie. You will miss it if you don't know about proofs.