I quite like nevermindpopfilm's thoughts on The Prestige that he posted in another thread:

Sure. Magic was representative of God and the inability of Man to simply acknowledge that it was impossible for magic(God) to exist but we continue the charade rather than accept the brutality of it.

I think Jackman's line at the end summed it up for me:

The audience knows the truth- that
the world is simple. Miserable.
Solid all the way through. But if
you could fool them, even for a
second, you could make them wonder.
Then you got to see something very
special...

Continually, Angier does not want to believe that the trick could have been done through such simple, practical means.

Although things get a bit muddled with this theory when people consider Tesla's cloning machine. Shouldn't the machine only confirm the existence of the supernatural?
But science does a lot of crazy things. Who says the machine is something supernatural because it does something that we have not yet developed. I'm sure something that we take for granted like electricity would seen supernatural to the uninitiated.

Certainly...a TV box with talking faces would seem supernatural to puritans 200 years ago.

I see this rivalry as the representation of how far an artist is ready to go for what he believes, how much he needs to sacrifice to be the best. obsession, power, destruction.