According to this Catholic Encyclopedia:
http://www.newadvent.org/cathen/06068b.htm fideism is a heresy. Fideism is defined as: A philosophical term meaning a system of philosophy or an attitude of mind, which, denying the power of unaided human reason to reach certitude, affirms that the fundamental act of human knowledge consists in an act of faith, and the supreme criterion of certitude is authority. A philosophical term meaning a system of philosophy or an attitude of mind, which, denying the power of unaided human reason to reach certitude, affirms that the fundamental act of human knowledge consists in an act of faith, and the supreme criterion of certitude is authority. But I talked to one lapsed Catholic and she seemed to believe that fideism was what she was taught in the Catholic Church. According to this encyclopedia entry (1) a good Catholic is suppose to believe in God because His existence is proved using reason (2) Believing on faith alone is a no-no and a dumb idea since it is really just boils down to belief _base_d on arbitrary authority. Is this encyclopedia correct about the nature of Catholic teachings on fideism. Interesting, the encyclopedia fits somewhat with the fact that most people who believe in God _base_ their belief on either a direct experience with God or on what they consider proof like the need for a first cause. (from a poll reported in the book Why We Believe by Shermer)