A brilliant aphorism on doubt:
“[Doubt] is altogether a pernicious companion which has its origin not in the good creation of God but in the Nihil — the power of destruction — where not only the foxes and rabbits but also the most varied kinds of demons bid one another “Good night.” There is certainly a justification for the doubter. But there is no justification for doubt itself (and I wish someone would whisper that in Paul Tillich’s ear). No one, therefore, should account himself particularly truthful, deep, fine, and elegant because of his doubt. No one should flirt with his unbelief or with his doubt. The theologian should only be sincerely ashamed of it.”
Karl Barth, Evangelical Theology: An Introduction (Eerdmans 1992), p. 131.