Why doesn't rioting happen more often?
Many commenting on the recent riots and looting in England betrayed a short-term and local perspective.
They asked how such a thing could have happened, as if peace and good order are the natural condition of men, so that departures from it need some special explanation, such as the injustice of cutting government spending or the racism of the police.
Yet rioting and looting are profitable but enjoyable. Indeed, enjoyable may be putting it too politely.
Creating mayhem, inducing fear in others and destroying what they have laboured to build are intoxicating experiences, especially for young men. The mystery is not how an eruption of such passions could have happened at all, but why it does not happen all the time.
"What needs explaining is why they don't occur, not why they do occur. And they don't occur in England, on the whole," observes philosopher Roger Scruton.
A modern Briton enjoys a level of security - both in his person and his property - that would strike our distant ancestors, and many people living in other parts of the world today, as near miraculous. How have we achieved it?
Not through simple authoritarianism. It would take only a small percentage of the population to become lawless all at once, to take what they like and damage what they dislike, and the police would be overwhelmed.
We enjoy civil order in Britain only because people choose to follow the rules. We live in a society of voluntary co-operation, neither chaotic nor oppressive. This is an extraordinary achievement, which must be understood to be maintained.
Many left-wing commentators, including Harriet Harman, the deputy leader of the Labour Party, claimed that the recent riots were caused by the "social injustice" of cutting government spending from 48% of gross domestic product (GDP) to 46%, as the government plans to do over the next four years. Implicit in this is the idea that civil order depends on social justice.
The idea here cannot be that material hardships cause unruly behaviour. Those who rioted in England in August are much better off than more law-abiding people in other countries and more law-abiding Englishmen from earlier decades.
No, the thesis must be psychological. It must be that the perceived injustice of society causes the unwillingness to play by the rules. The political philosopher George Klosko put it the other way round: "A necessary condition for people to be willing to obey the law is their perception that the political system - the overall system of distribution of benefits and burdens - is acceptably fair."
I don't buy it. For a start, people disagree so much about what is fair and what not, that we might expect a large minority of the population to consider any social arrangement unfair. Yet only a tiny minority of Britons fail generally to abide by the rules.
It is precisely because our sense of fairness is insufficient to prevent us from coming into potentially lethal conflict with each other that we need a system of laws, enforced by some third party.
This was the fundamental insight of Thomas Hobbes, the 17th Century philosopher, who argued in his Leviathan that the proper function of the state was to protect us from the horrors of living without one.
In a state of nature, he argued, life would be "nasty, brutish and short". Our sense of fairness cannot stop us from coming into conflict with each other because we all want roughly the same things, resources are scarce and we are all of roughly equal power. (No matter how strong you are, I can still kill you while you sleep.)
In a state of nature we would all be at war with each other.
"Hobbes' answer is a thought experiment," explains political philosopher Quentin Skinner, "It is as if we each agreed with each other upon a representative - someone whose will shall count as our will. Now, we could agree that that person - it's obviously a fictional person - is all of us. That would be democracy.
"Or we could agree on some person - that would be monarchy; or a group - that would be aristocracy. So representation is tied as closely as possible to authorisation. Now you see ingeniously why you have a moral obligation to obey the state because it's almost a rational obligation. The agent of the state when he or they or she acts is performing your will."
We benefit from setting aside our native sense of justice and complying with a system of laws. At least we do if we can expect others also to comply with those laws.
And we can expect others to do so only if the law is consistently enforced. In this way, coercion is the foundation of our voluntary cooperation.
This is not an argument for authoritarianism or for the absolute power of sovereigns, as Hobbes believed it to be.
On the contrary, a liberal legal regime, which constrains people no more than required to keep us safe from each other, is most likely to sustain voluntary compliance.
We live in a society where most of us need fear neither our neighbours nor the police. That is a precious achievement.
Maintaining it requires politicians, judges and policemen to remain committed to the rule of law. They must defend our expectation that others will be held to the rules that we voluntarily abide by.