According to Jamie Whyte, the proper assignment of fulfillment conditions to an agent’s set of desires proceeds in three steps. First, one identifies various desire extinction and behavioural reinforcement conditions to obtain the fulfillment conditions of a certain subset of the agent’s desires. With these fulfillment conditions in hand, one then appeals to a principle connecting desire fulfillment conditions with belief truth conditions to obtain the truth conditions of a number of the agent’s beliefs. Finally, one uses these belief truth conditions to generate, via a third principle, the fulfillment conditions for the remaining desires. There is, however, a very straightforward reason why this strategy cannot yield the required results.