One does not learn anything except by believing something, and -- conversely -- if one doubts everything one learns nothing. On the other hand, believing everything uncritically is the road to disaster. The faculty of doubt is essential. But as I have argued, rational doubt always rests on faith and not vice versa. The relationship between the two cannot be reversed.

Proper Confidence: Faith, Doubt, and Certainty in Christian Discipleship (ed. 1995)