  In a fairly early phase of the debate over the causal status of reasons for action, Norman Malcolm [1968] and Charles Taylor [1964] defended the thesis that ordinary reason explanations stand in potential rivalry with the explanations of human and animal behavior the neural sciences can be expected to provide. More recently, Jaegwon Kim [1989] has revived this issue in a more general way, seeing the two modes of explanation as joint instances of a Principle of Explanatory Exclusion. That Principle tells us that, if there exist two ‘complete’ and ‘independent’ explanations of the same event or phenomenon, then one or the other of these alternative explanations must be wrong. Influenced by Davidson, many philosophers reject more than just reason-to-action laws. They believe, more generally, that there are no laws that connect the reason-giving attitudes with any material states, events, and processes, under purely physical descriptions. As a consequence, commonsense psychology is not strictly reducible to the neural sciences, and this means that reason explanations of action and corresponding neural explanations are, in the intended sense, ‘independent’ of one another. But, detailed causal explanations of behavior in terms of neural factors should also be, again in the intended sense, ‘complete.’ Hence, Explanatory Exclusion affirms that either the reason explanations or the prospective neural explanations must be abandoned as incorrect. Since we are not likely to renege upon our best, most worked-out scientific accounts, it is the ultimate viability of the reason explanations from commonsense ‘vernacular’ psychology that appear to be threatened. The issues here are complicated and controversial — particularly issues about the proper understanding of ‘theoretical reduction.’ However, if Explanatory Exclusion applies to reason explanations of action, construed as causal, we have a very general incentive for searching for a workable philosophical account of reason explanations that construes them as non-causal. Just as certain function explanations in biology may not reduce to, but also certainly do not compete with, related causal explanations in molecular biology, so also non-causal reason explanations could be expected to co-exist with neural analyses of the causes of behavior.