In Chapters XI and XII, we defended a broadly functionalist theory of beliefs and desires. According to this theory, the belief that it is about to rain (for example) is a physical state, identified not by its intrinsic physiological properties but by its role in producing behaviour. As we put it before, the ‘what it is to be what it is’ of a belief is its function. Now, can we generalise this approach to cover other types of mental state? What about sensations – such as feeling pain, for example? Can we give a functionalist analysis of these, or must we look for a quite different kind of account?

There are conspicuous differences between sensations and states like belief and desire. Take the case of feeling a painful tingling. This experience is not about something in the way that beliefs or desires, hopes or fears are about something: we have no locution of the form ‘Jack tingles that p’ or ‘Jill has a pain that p’ Generalising, we cannot ascribe simple bodily sensations by using a ‘that’-clause – i.e. sensations are not propositional attitudes in the sense explained in X.1. Because of this rather fundamental difference, we perhaps shouldn't expect a theory of sensations like pain to run exactly parallel to our account of attitudes like belief. Still, let's begin by briefly considering the prospects for a functionalist theory of pain.

What is the function or causal role of pain? At bottom, it seems plausible to say, the business of pain is at least typically to alert us to bodily damage or malfunction, and to spur us into protective or avoidance behaviour.