JULIAN BAGGINI

Do you know the real reason why the Normans won in 1066? The night before the battle of Hastings, the French gathered together and prayed for victory. The English gathered together and got drunk.

OK, there were other reasons, too, and I haven't exactly double-checked my sources on this - but, let's face it, it wouldn't be surprising if this were true. The only thing new about binge drinking is the phrase itself. And, in this respect if not any other, Scotland is no different from England.

The question of how to deal with the problem has been debated across the country following the death of Garry Newlove. This week, Ken Jones, the president of the Association of Chief Police Officers, said teenage drinking had reached epidemic proportions. There have been calls not only for the legal age at which alcohol can be puchased to rise to 21, but for alcohol prices to rise steeply.

It would be good if we could apply some sort of consistent principle to determine how the law should be, because it certainly seems we're currently in total contradiction. We live in a country in which the Bruichladdich distillery in Argyll can win the Queen's Award for Industry for its high-class alcohol-dealing, but the meaning of Her Majesty's Pleasure for entrepreneurs trying to do the same for cocaine or marijuana is quite different.

Scotland led England in liberalising drinking hours, but then also led it in clamping down on smoking in enclosed public places. So what principle is at work here: freedom of individual choice or benign paternalism?

It's not surprising there is this tension in the law because the same tension exists in moral theory. On one side there are those who think the right course of action is that which improves the welfare of as many people as possible, and if this means taking away a few choices from people, that's fair enough.

On the other, you have those who say what takes pole position in moral deliberation is people's right to choose how to live their own lives. It doesn't matter if this makes them less happy, because taking choice away would make them less human, which is a much worse fate.

The same dichotomy plays out in the intellectual tug-of-war over how much we should limit access to dangerous drugs. The general welfare pulls against the freedom of the individual, only to get pulled back if it manages to win too much ground.

Such a contest will never be won, because neither position is adequate by itself. John Stuart Mill seemed to recognise this. He is famous for promoting utilitarianism, the doctrine that what is right is what promotes the greatest happiness of the greatest number. The principle is often invoked to justify curbs on freedom. But he also advocated the "harm principle", which states that we are never justified in infringing the liberty of another against his or her will, other than to protect others. What people do to themselves is their own business.

Mill thought these two principles of harm and utility were perfectly consistent, but perhaps he was too optimistic. Maybe personal freedom and general welfare are two desirable goods that we cannot always have.

Alcohol might be one such case in point. I'm a regular drinker, but I can see that we might be a happier lot if the whole brewing industry was shut down, such is the misery caused by excessive drinking. The number of fatal accidents, murders, attacks and premature deaths caused by excessive drink is staggering.

So how to balance the claims of liberty and welfare? Another key concept in ethics is autonomy: the capacity we have to govern ourselves. Autonomy, however, is not just something we exercise in the absence of constraint: it is something that can be fostered or diminished. For instance, alcoholics are not exercising their autonomy when they pour another drink, because it has actually been eroded by their addiction.

Once you see this, it should be obvious that autonomy is not the same as unfettered freedom. That's why it is right sometimes to ban things which threaten to chip away at it.

Public policy, therefore, is not so much a mass of contradictions as an attempt at a morally difficult balancing act. Anyone who thinks freedom or the general good is a trump card that can magically dissolve this difficulty is guilty of simplistic thinking about a horribly complex issue.

Julian Baggini begins a regular column with The Herald later this month.