The cat is crouched low to the ground, whiskers brushing grass. It inches forward in minute movements, eyes drilling towards two sparrows just ahead. It tenses, set to spring. The birds prance like sparring boxers, unaware. But then the cat’s muscles relax. The moment wasn’t quite right – something in the angle or the air. It creeps another inch closer, and another, tautens again, then bursts forwards.
Cats make decisions. And they make decisions about similar kinds of things to us: whom to hang out with and whom to avoid, what to have for dinner tonight and where to get it from. By the standards of most life on Earth, cats have highly sophisticated brains. This gives them a range of behavioural options – a degree of freedom, we might say.
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.