The church (quite naturally) encourages faith on the part of its constituents. But faith is not the absence of doubt. Indeed, doubt is not the opposite of faith; the opposite of doubt is certainty. And where there is certainty, there is no need for faith. Often those with the greatest faith have the most doubt. Faith should be the resolve to act with the whole person in keeping with what one only knows to be true in a part of the person.
It is a mistake to think that faith and doubt are a single vacillating element. The two, remain two and are never one. But they may coexist inside of one person. Vacillation does not occur between the two. It occurs at the level of the will in response to the force of the two. The will must choose. The man of faith is not the one who defeats doubt, but rather the one who overwhelms it with a “mighty unity” – a charge of the whole person toward the object of faith.