Abstract
Carl Hempel has proposed the following model for explanations by reasons. A was in a situation of type C. A was a rational agent at the time. In a situation of type C, any rational agent will do X. Therefore, A did X.According to Hempel overcomes the shortcomings of alternative accounts of explaining by reasons such as William Dray's model, in that the so-called evaluative principle is replaced by an empirical law. It is William Dray's contention that to understand the action of a rational agent is to see that his action was appropriate in his situation. Following Dray this then means that in explaining such an action one makes use of a normative ‘principle of action', not an empirical law, which has the form ‘when in a situation of type C1… Cn the thing to do is X'.