[andrewflnr]

There's pretty-good-guess faith and blind faith. Mathematical axioms and believing what other people tell you about science you haven't observed yourself are examples of the former. Belief in God varies between the two from person to person.

[nitrogen]

There's a way of formalizing this, so we don't have to rely on the imprecise and loaded word "faith": Bayesian probability, e.g. as described on http://lesswrong.com. See also http://rationality.org.