I do believe in what Cardinal Newman called the “development of doctrine” — though not precisely in the way that Newman did — but I am skeptical of the idea of “progressive revelation.” It leads to the belief that whatever is progressive — whatever has developed, has emerged — is ipso facto revelation. But if you don’t believe that, then you have to be able to distinguish between progressive developments that really are authentic expressions of the Gospel and those that aren’t. And in order to do that you have to criteria for deciding, and those criteria will necessarily not involve the notion of what’s “progressive” because the progressive is precisely what you’re evaluating. The idea of progressive revelation is therefore a problem, not a solution.