Let us be seeing:

"an irrational but usually deep-seated belief"
Microsoft® Encarta® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

I beleave in God...

“Creo quia absurdum est”
"Nihil curo de ista tua stulta superstitione."

Niels Bohr kept a horse shoe over his desk. One day a student asked if he really believed that a horse shoe brought luck. Bohr replied, "I understand that it brings you luck if you believe in it or not."