Two modes of thought.

Philosophy typically works using deductive reasoning.
Science typically works using inductive reasoning.
Religion typically doesn't work at all, using any reasoning.


Some definitions...

Deduction:

One makes up one's mind on something, then uses logic and whatever appropriate logical loopholes can be imagined and convincingly argued, to show that this opinion is the way "it really is." In the end charisma and/or intimidation often come into play.


Induction:

Same as deduction, except one additionally gathers facts that support one's hunch, ignores those that don't, then arranges and presents the "good" facts so as to make it seem that Nature herself agrees on the point. This is more convincing than deduction, so science generally beats philosophy the way paper somehow beats rock.