Trust and *reason.

Abstract

Entering into a trust relation enables you to do things you couldn't otherwise do. As trusted, you can help others do or believe what they have reason to do or believe. As trusting, you can get such help when more private resources run out. I begin by contrasting the way you address someone when you intend him to trust your testimony or advice with the way you might address him if you wanted merely to give him evidence that what you assert is true or to get him to do something. In inviting someone to trust you, you intend to give him a reason by a Gricean mechanism: on the basis of his recognition simply that is what you intend. Giving and getting reasons in this way rests, I argue, on the addressee's exercise of a distinctive species of rationality: the capacity to trust where and only where it makes sense to trust. I call this capacity <italic> fiduciary reason</italic>. I explain how an agent's capacity for fiduciary reason functions as an irreducible source both of epistemic reasons and of practical---prudential and moral---reasons. I then apply my conception of trust-based reasons to two debates in the theory of agency. First, I argue that the inclusion of an agent's fiduciary reason in a conception of his practical rationality vindicates an internalist view of practical reasons that accommodates the guiding insight of externalist views: that it always makes sense to think a gap might emerge between your motivational susceptibilities and what you have reason to do. I construe this gap as separating the motives you can reach by a private deliberation from those you can reach only by trusting another's advice. Second, I argue that fiduciary reason plays a crucial role in the diachronic species of practical rationality you manifest when you merely follow through on one of your own intentions. It is no more reasonable to follow through on an intention formed by an untrustworthy earlier self of yours, I argue, than it is to act on the advice of an untrustworthy interlocutor.