Gilbert Harman

Psychological explanation is a kind of functional explanation, like some biological explanation, where the relevant functions tend to have to do with perceiving and acting in relation to the environment. Pain serves as a kind of alarm system; perception allows an organism to get information about the environment etc. Although there are defenders of a narrow, more solipsistic psychological functionalism, the dominant trend has involved the wider version. In any event, the wider functionalism is clearly more plausible and methodological solipsism in psychology is incoherent.

Replies to three related arguments against wide functionalism. The first says that we are directly aware of intrinsic features of our experience and points out that there is no way to account for such an awareness in a purely functional view. The second claims that a person blind from birth can know all about the functional role of visual experience without knowing what it is like to see something red. The third holds that functionalism cannot account for the possibility of an inverted spectrum. All three arguments can be defused by distinguishing properties of the object of experience from properties of the experience of an object.

Simplicity is used in curve‐fitting and can be illustrated by Goodman's ‘new riddle of induction.’ Taking the simplicity of a hypothesis to depend entirely on the simplicity of the way it is represented does not work, because simplicity of representation is too dependent on the method of representation, and any hypothesis can be represented simply. An alternative ‘semantic’ theory also has problems. A ‘computational’ theory is defended that considers how easy it is to use a hypothesis to get answers to questions in which one is interested.

Intentions are distinct real psychological states, not mere constructs out of beliefs and desires. One intends to do something only if one believes one will do it. Positive intentions are to be distinguished from negative and conditional intentions. All intentions are self‐referential and are to be distinguished from beliefs by means of differences between theoretical reasoning, which directly modifies beliefs, and practical reasoning, which directly modifies intentions. One can sometimes adopt intrinsic desires at will and one may pursue a plan in order to give significance to earlier acts.

Discusses how to explain the distinction between epistemic and non‐epistemic reasons while allowing epistemic reasons to be affected by pragmatic considerations of simplicity, coherence, and conservatism. After noting difficulties with trying to explain epistemic reasons in terms of connections with truth or the goal of believing what is true, the chapter discusses issues about the nature of probability, suggesting that epistemic reasons connect with conditional probability in a way that non‐epistemic reasons do not.