From a comment I posted elsewhere:
I don't actually know what faith is. It is not simple intellectual assent--i.e., belief. The bible speaks of some who believe but are lost. Nor is it "blind." Hebrews 11 has the faith hall of fame, and lists people who did not need blind faith for they saw and spoke to god. Abraham's faith was hardly blind, with the execption that he had faith that God's promise of redemption would be fulfilled in his future. If blind faith was the ultimate virtue, Gideon (who demanded physical proof) would stand condemned--instead he shows up in Hebrews 11 as a faith hero. Faith (πίστις), I think, is closer to trust than to believe. As Grudem puts it, which works for me, it's coming to God and saying: "I got nothing."