The standard model of human motivation, sometimes called the ‘Humean’ theory of motivation, is that it takes a desire and a belief. Belief by itself will not suffice, unless the objects of belief interact with the agent’s desires. They must be things towards which there is some attraction or aversion. Some say that if desires are thought of as conscious states of mind, this is untrue. On the other hand, if they are thought of as no more than interpretations certified by the agent’s behaviour, then perhaps the model is trivial. But functionalism rescues the Humean theory, seeing ‘desire’ as a respectable theoretical category, identified by its role in systematizing the explanation of agents. Salient questions include whether we always do what we desire to do, whether we can control our strongest desires, and how motivation by desire compares with motivation by principle. Major philosophies of life, including Buddhism and Stoicism, have presented the overcoming of desire as an ideal. See apathy, eros, summum bonum.