What is faith (or Faith if you prefer)...? and, whatever it is, is it philosophically defensible?
The Stanford Encyclopedia of Philosophy has a fine brief article on the subject, and it lists seven different "models" of faith.
I'll just list them here and link you to the article because I'll feeling lazy today.
1) The purely affective model -- faith equals confidence;
2) The special knowledge model -- faith means that God has revealed specific truths, and the recipient of the revelation accepts them as such;
3) The belief model -- faith is simply another name for the belief that God exists;
4) The trust model -- my faith in a God isn't the belief that God exists, but a subsequent fact, a sense of trust in the Being whom I already believe to exist;
5) The doxastic venture model -- James' will to believe may fit here. This model takes faith to be a practical commitment to the proposition that God exists, even if it coincides with an acknowledgement that the evidence is inadequate;
6) The subdoxastic venture -- a practical commitment to the consequences of the proposition that God exists, even if it coincides with an acknowledgement that the person making the commitment doesn't actually believe that God exists. Note the difference between this and the above. Pascal's wager may fit here, although Pascal believed that belief would eventually come to the doubter taking holy water etc. on this basis;
7) The hope model -- faith may simply mean hoping that a proposition is true and keeping one's life open to that possibility.