If the equation is read the other way, from right to left, then there is at the foundation a belief: the belief that ϕ is a reason for action. It is a special kind of belief, because it picks out or represents reasons. But it is a belief that carries concern with it. It is often said that Aristotle believed in this direction of explanation: its slogan is that to desire something is to see it as good. It is as if desire answers to a perceived truth.
