I think therefore I am, I think

But the American neuroscientist Benjamin Libet has shown that before every such movement, there is a distinctive build-up of electrical activity in the brain. And this build-up happens about half a second before your conscious ”decision” to move your arm. So by the time you think, ”OK, I’ll move my arm,” your body is halfway there. Which means your conscious experience of making a decision - the experience associated with free will - is just a kind of add-on, an after-thought that only happens once the brain has already set about its business. In other words, your brain is doing the real work, making your hands turn the pages of this magazine or reach over for your cup of tea, and all the time your conscious mind is tagging along behind.

But if this is true, the implications for our systems of morality, of crime and punishment, are shattering. We only punish those we think voluntarily did wrong - not those who literally had no choice but to act as they did. But if there is no free will, then no one has ever had a choice but to act as they did. That Eve ate the apple was as predetermined as the leaves falling to the ground in autumn. None of us could ever truly be said to be responsible for our actions. In very different ways, three new books tackle the question of whether we are free and what it means if we are not.

There is already ample evidence that prison is effectively where society sends those whose brains do not work properly. A report released last month suggested over a quarter of the UK’s almost 80,000 prison population have an IQ of lower than 80 and suspected learning disabilities, such as forms of autism and dyslexia. Another study carried out at the Young Offenders’ Institute in Aylesbury showed that if prisoners were given minerals and fatty acids essential for proper brain functioning, they committed 37 per cent fewer violent offences.