This chapter deals with the role of reason in human thought and action. A powerful argument against physicalism is the lack, so far, of a suitable account of ‘mental causation’, that is, of the role of reason in brain processes. The problem is often formulated as the question of how the mental properties of brain events can be causally efficacious. Instead, this chapter reformulates the problem in terms of two questions: how is it that series of mental/neural events come to conform to rational (as opposed to merely causal) patterns; and what difference does the possession of mental capacities make to the causal efficacy of an organism's interaction with its environment? The role of beliefs and reasoning in behavior is discussed with respect to these questions.
Keywords: mental causation, brain, rational patterns, beliefs, reasoning