Discussion of Jackson and Pettit, ‘Functionalism and Broad Content’

Abstract

In their recent paper 'Functionalism and Broad Content', Frank Jackson and Philip Pettit introduce an important distinction between what they call causal process and causal program explanations.' In this discussion I want to examine this distinction. I will argue that although the distinction is important and correct, it does not quite do the work Jackson and Pettit require of it. The distinction is introduced in the context of what we might call the causal objection to the use of content in psychological explanation.2 It is now well known that the contents of mental states are broad in the sense of being essentially worldinvolving. The Twin Earth examples of Putnam and Burge have led to the now fairly well accepted view that the objects, properties, and relations existing in the environment of an organism are essential determinants of that organism's mental states.3 The situation can be correctly pictured thus. The content of a mental state is constituted by two factors; (a) the causal role, and (b) the referential properties, of that state.4 It is the referential properties of the mental state which make that state essentially world-involving, hence which makes the content of that state broad. But the referential properties of a mental state are causally irrelevant to the interactions that state enters into with other mental states, and to the role it plays in bringing about behaviour. Many have seen this as indicative of a problem with the use of content in psychological explanation. Subtleties aside, the argument runs as follows. Since the referential properties of a mental state are causally impotent with respect to the bringing about of behaviour, they can play no role in the explanation of behaviour. But mental content is (at least partly) constituted by the referential properties of mental states. Therefore, mental content is unsuitable for the causal explanation of behaviour.5 Jackson and Pettit argue that the causal objection to the use of content in