One can be a true believer in anything: psychic ability, Christianity or, as Bertrand Russell classically suggested (with irony), in the fact there is a teapot orbiting the earth. I could believe any of those things with total conviction. But my conviction doesn't make them true. Indeed, it is something of an insult to the very truth I might hold dear to say that something is true just because I believe it is.
Derren Brown