 It is a commonplace that explanation in cognitive science is structured into different levels. Given our aims, we can illustrate this idea through the classical tri-level hypothesis formulated by David Marr (1982). Suppose that one wants to explain a certain cognitive capacity, say, vision (or mindreading, or moral judgment). The first level of explanation, the most abstract one, consists in describing what the cognitive capacity does—what task it performs, what problem it solves, what function it computes. For example, the task performed by vision is roughly “to derive properties of the world from images of it” (Marr 1982: 23). The second level of analysis specifies how the task is accomplished: what algorithm our mind uses to compute the function. Importantly, this level of analysis abstracts from the particular physical structures that implement the algorithm in our head. It is only at the third level of analysis that the details of the physical implementation of the algorithm in our brain are spelled out.