TERRORISM, writes AC Grayling, is the aggression of the weak. It is "impotence made terribly potent by what... malignant rage is prepared to do".

So begins a concise little essay on Vengeance which runs to not much more than a page and yet is devastating for the calm precision with which its author sets out the right response to terrorism. Civilised society, Grayling writes, involves a fundamental contract between its citizens by which they agree to live and which enables them to co-exist peacefully. An act of terrorism is a vile attack on that contract.

There are several correct responses, he says - bringing the perpetrators before a court of law and making them suffer the penalties of the contract they tried to destroy; offering friendship to the communities from which terrorism sprang; and refusing to give way to fear of further terrorist attacks.

And there is one wrong response. "The wrong response is to resort to meet terrorism with terrorism - for that also destroys the contract on which civilisation rests, and which is more important than present anger or past offences."

Vengeance is just one of 60 essays in The Reason Of Things, a new collection of the philosopher's work which brings the same calm rationality to a consideration of many of the issues which face us today. Grayling writes with devastating clarity on everything from religion, evil, sex and morality to anger, politics, justice, liberty and loss.

An antidote for the ill-considered ranting which too often passes for argument in these days of instant opinion - and a joy to read.

Updated: 08:59 Wednesday, August 06, 2003