I offer Jimmy a dollar to wiggle his ears. He wiggles them because he wants the dollar and, as a result of my offer, thinks he will earn it by wiggling his ears. So I cause him to believe something that explains, or helps to explain, why he wiggles his ears. If I push a button, and a bell, wired to the button, rings because the button is depressed, I cause the bell to ring. I make it ring. Indeed, I ring it. So why don’t I, by offering him a dollar, make Jimmy wiggle his ears? Why, indeed, don’t I wiggle them? If I ring a bell by pushing a button, why don’t I wiggle Jimmy’s ears by offering him a dollar?
That is a question that has always vexed a compatibilist’s vision of human freedom. If an intentional act–say, wiggling one’s ears in order to earn a dollar–is caused by one’s beliefs and desires (the reasons one has for wiggling one’s ears), then, by the transitivity of the causal relation, it appears to follow that it is (also) caused by whatever causes one to have those beliefs and desires. But the causes of belief and desire are often (in fact, if we trace the causal chain far enough backward, always) factors over which one has no control. So intentional behavior is often (or always) something one is made (caused) to do by factors over which one has no control. This, however, robs intentional behaviorand, presumably, also voluntary action–of its autonomy. Deliberate acts–Jimmy wiggling his ears to earn a dollar–have the same causal structure as does a bell that rings because a button is pushed. The only difference is the switch.