The modern world speaks a great deal about autonomy, and the more the modern secularist emphasizes his or her autonomy, the more the faithful Catholic doubts its value. However, as I pointed out in my review of Linda Trinkaus Zagzebski’s recent book (see Epistemic Authority: Preferring the True and the Good to the Self), a legitimate emphasis on personal autonomy is implicit in the Christian doctrine of conscience. We cannot escape the need to make our own decisions about truth and goodness.

In making these decisions, many other people can help us, and we can come to recognize various authorities over what we believe. That’s the point of Zagzebski’s book, which I highlight in the review. She destroys the claim of epistemic egoism—the claim that we...