A voluntary decision to commit yourself to a proposition does not, by itself, amount to faith. Even the decision plus a bunch of good reasons for your decision still are not sufficient for a sincere belief, let alone a conviction. Faith as Adams conceives it moves in a space bounded on the one side by subjective certainty (which Calvin ascribed to faith, but Adams does not) and on the other side by the subjectively incredible. Within that space it is often hard to tell, subjectively, how far one’s faith is supported by one’s sense of what is more plausible, and how far by willpower. But both, Adams thinks, are normally involved.
It’s also not easy to specify what more is required beyond willpower. As a first approximation we might try to identify the requisite feeling as at least a minimal degree of confidence in the view that you hold. This is not adequate as it stands, however. If you are depressed, you may doubt that your life is worth living. Yet in precisely this sort of case it is very likely both possible and right for you to cling to faith that your life is worth living.
Is it sheer willpower if you do cling to it? Surely not. Willpower can’t give you a belief in a hypothesis that is not “live” for you, as William James put it. Probably no amount of willpower could give you the belief that 2+2=5, or even that you will never die. Nor could sheer willpower give you the belief that the number of bald eagles that laid eggs in 1993 was even rather than odd. If you succeed, against emotional appearances, in clinging to the faith that your life is worth living, the clinging must feel different from trying to believe one of those patently false or humanly undecidable propositions. Perhaps you feel some level of trust in some reasons for clinging to faith, or perhaps giving up faith “feels wrong” for you.
But “confidence” is hardly the right word here. It suggests a state of feeling that is much less troubled than faith has often to endure. In some ways Adams prefers the word “courage,” provided he can make clear that he does not mean courage as a mainly voluntary virtue. He means courage in a sense in which it is felt more than chosen, the sense in which it might be a direct product of being “encouraged.” In Greek it would be tharsos rather than andreia; in German it would be Mut rather than Tapferkeit. The courage of which Adams would speak is not sheer willpower or voluntary determination. We may hope that such emotions are responsive to reality. They must be, if we are to have much chance of living a life both good and grounded in reality. In a sense indicated by Adams’ argument (not to mention other senses), “the just shall live by faith.”
Image: " Abraham's Journey from Ur to Canaan " By József Molnár - Own work (scanned), Public Domain, https://commons.wikimedia.org/w/index.php?curid=2684048