Talking about Epicureanism at The Idler Academy last night, I was encouraged that people responded warily to Epicurus' attitude towards friendship. It is radically self-interested. Though he can celebrate friendship 'dancing around the world' announcing blessedness, and he wrote a moving letter to a friend on the day he died, his friendliness is as egoistic as his hedonism: value your friends only insofar as they can help you.

Is that really friendship, individuals worried? Isn't it rather using others for your own good? Well yes, I replied, but don't think that is so unusual.

Yesterday too, a report on 'nudge' and behavioural change was published. Nudge is radically Epicurean when it comes to using others. Are you obese? Ditch your fat friends and take up with thin ones: that's more effective than any diet. Do you smoke? Shun smokers - yes, particularly those in your family. Or more generally, do you want to enhance your wellbeing? Cross to the other side when approached by anyone who doesn't smile.

And in the process, the world fills up with self-interested, happiness maximisers who are as cruel and calculating as a News of the World journalist. 'Love' others and secure your own needs, it teaches - in the name of making the world a better place. It fails to add, and watch your supposed friends ditch you for not satisfying their own egoistic concerns.

Emerson, for one, had a much better plan. If you want to have a friend, he advised, be a friend.