Since ancient times, thinkers have pondered whether we freely choose our actions or if they are determined by forces beyond our control. That debate has been given new impetus by scientific discoveries that have advanced our understanding of the causes of our behaviour. Robert Sapolsky, a Stanford University neuroscientist and recent guest on the podcast “Lives Well Lived,” which I co-host with the Polish philosopher Katarzyna de Lazari-Radek, is one of these science-based determinists.

In his book "Determined: A Science of Life Without Free Will", Sapolsky argues that free will is an illusion. Consider Joe, who decides that he should eat a healthy diet. He meets a friend at a cafe, and the friend orders a particularly tempting slice of cake, and urges Joe to order one, too. But Joe resists. He may think he exercised his free will and deserves some credit. No, Sapolsky would say: he was able to choose not to order the cake because of his genes, or perhaps because of the way he was brought up – in any case, because of factors over which he had no control.

Because our actions are determined, Sapolsky says, we are not morally responsible for them, and do not deserve praise or blame for what we do. He deplores the fact that all over the world, in everyday life, from courtrooms to classrooms, at award ceremonies and in eulogies, we cling, with “ferocious tenacity” to our belief in free will.

What is wrong with this argument is not the claim that everything has a cause, nor the belief that everything in the universe, including our behaviour, is determined. We can grant that if someone knew everything there is to know about our genes and our environment, they could predict our behaviour. The flaw in Sapolsky’s argument, and that of many others before him, is that he fails to recognise the distinction between behaviour that results from a choice we make and behaviour that does not.

Consider George and Mary. George develops a grudge against his neighbour, who often ignores him when they pass each other on the street. George knows that every morning the unfriendly neighbour goes to a nearby station to catch a train to work, and George decides that this creates an opportunity to get rid of him. George follows his neighbour to the platform, waiting for an opportunity to push him in front of the train as it arrives.

For several days, the neighbour stands too far back from the edge, and George cannot carry out his plan. But he persists, until one day the neighbour stands close enough to the edge for George to give him a hard push. The neighbour falls in front of the train and is killed.