This article offers a functionalist account of trust. It argues that a particular form of trust—Communicated Interpersonal Trust—is paradigmatic and lays out how trust as a social practice in this form helps to satisfy fundamental practical, deliberative, and relational human needs in mutually reinforcing ways. We then argue that derivative (non-paradigmatic) forms of trust connect to the paradigm by generating a positive dynamic between trustor and trustee that is geared towards the realization of these functions. We call this trust’s proleptic potential. Our functionalist approach does not only provide important insights into the practice of trust and its place in the broader web of social life, but also illuminates existing philosophical debates. First, pointing out how opposing theoretical accounts of trust each capitalise on only one of its functions, our paradigm-based approach reveals why they each contain a kernel of truth but are also deficient: the optimal realization of each function is tied to the existence of the other functions as well. Second, we show how a functionalist re-orientation can illuminate two recent disputes regarding (i) the question whether trust is explanatorily two- or three-place and (ii) whether (and to what extent) we can decide to trust others.