So what really works? Treatments in jail do some good, but it’s mostly too late: finding a family and a job or just growing older make most prisoners eventually give up crime.

It is now possible to quantify people’s levels of happiness pretty accurately by asking them, by observation, and by measuring electrical activity in the brain, in degrees from terrible pain to sublime joy.

The strongest predictor of unhappiness is anyone who has had a mental illness in the last 10 years. It is an even stronger predictor of unhappiness than poverty – which also ranks highly.

My mother begged doctors to end her life. She was beyond the physical ability to swallow enough of the weak morphine pills she had around her. When she knew she was dying I promised to make sure she could go at a time of her choosing, but it was impossible. I couldn’t help.

How do you make any sense of history, art or literature without knowing the stories and iconography of your own culture and all the world’s main religions?

Islam, Christianity and Judaism all define themselves through disgust of women’s bodies.

Nothing keeps people together like the exalted conviction that they alone are to be spared that eternal anguish of hell fire to which everyone else will be condemned.

Islam, Christianity and Judaism all define themselves through disgust of women's bodies.

Feminism is the most revolutionary idea there has ever been. Equality for women demands a change in the human psyche, more profound than anything Marx dreamed of. It means valuing parenthood as much as we value banking.

What is all that ministerial toil and effort for, if not a constant attempt to allow the greatest number to live in as much happiness as possible?