It is often thought that sci­ence has shown that there is no such thing as free will. If all things are bound by the same imper­son­al cos­mic laws, then (the sto­ry goes) our paths are no freer than those of rocks tum­bling down a hill. But this is wrong. Sci­ence is giv­ing us a very pow­er­ful and clear way to under­stand free­dom of the will. We have just been look­ing for it in the wrong place. Instead of using an elec­tron micro­scope or a brain-scan­ner, we should go to the zoo.