Faith (Greek: pistis) means an attitude (and/or a decision) of trust, confidence, assurance in the face of uncertainty (things hoped for but unseen). It does not mean “believing the right propositions.”
Consider an athlete faced with making an uncertain play under difficult conditions. Most athletes know that if they act with all the confidence/assurance they can muster—as if the outcome is actually certain—they have a better chance of making the play than if they just give it a half-hearted attempt.
Consider an athlete “in the zone.” She is playing with an unexamined sense of assurance and confidence, and a concomitant attitude of praos (translated in English as “meek,” but in French Bibles as “debonair” ). Most seem to report that being in the zone carries with it a profound sense of coherence, harmony and even joy.
Athletes practice disciplines (ascesis) to facilitate “getting into the zone.” Some religious folks (theist or not) practice various ascesis to live in an existential attitude of faith and praos. One might call that the spiritual “zone.” From a Christian point-of-view, that means, in part, opening oneself to grace—without insisting on a pre-conceived outcome, or attempting to limit the wide-ranging activities of the Spirit (pneuma that “blows where it wills” without anyone being able to see “whence it comes or where it goes.”
Such an existential faith, therefore, involves an openness to possibility—not the closure of possibility.
In one sense, that may be its own reward—even if you don’t make the play, it seems to be on the whole a richer way to live. Nevertheless, Paul’s definition appears not to be so inscrutable as I once thought. Even for a non-religious person—the next time you’re deep in the rough, with a thick stand of trees between you and the “fair way.”
EDIT: Despite preparation, athletes also report that sometimes "being in the zone" just seems to "happen." Extending the analogy to religious parlance, this would be akin to being "in a state of grace."