Causal Relevance and Heterogeneity of Program Explanations in the Face of Explanatory Exclusion

In everyday causal explanations of human behaviour, known generally as 'folk psychology,' the causal powers of the mental seem to be taken for granted. Mental properties such as perceptions, beliefs, and desires, are all called upon in causal explanations of events that are deemed intentional. Jaegwon Kim's exclusion principle has led him to deny mental properties causal efficacy unless they are metaphysically reduced to physical properties, but what of their causal relevance? By giving up the assumption of causally efficacious mental properties, has Kim put into question the explanatory value of explanations with mental descriptions? In other words, if a lower order neurological causal explanation involving a causally efficacious property is at hand, does it make the higher order mental explanation irrelevant and therefore redundant? If we are to save the explanatory importance of higher order predicates, and thus the causal explanations of the special sciences and folk psychology, we need an account of how such properties can be relevant as opposed to irrelevant in causal explanations, even though they may not be causally efficacious. Frank Jackson's and Philip Pettit's notion of program explanation tries to do just this.