September 11, 2001 certainly gave America a wake up call, it was not invincible afterall. But what was the message that they got and was it the correct one?

Whilst taking analogies too far is clearly dangerous and absurd, used in a restrained manner they can help clarify a complex issue. It is with this in mind that I risk the analogy of the USA with a man in his mid-20's. America is a young nation but past it's infancy and possibly at the height of its powers, like many young men, it had a view of itself as invincible.

Regardless of what they might think, young men are not invincible, and it is often the smallest of organisms, bacteria, that demonstrate this in the most devastating fashion. So it was with America, it was not a superpower, or even a smaller nation, that demonstrated to America that they could be damaged but a group of a dozen or so men.

America's response was also sadly typical of many young men when their vulnerability is made apparent to them and that is dangerous and reckless bravado to prove that they have not been cowed by the misfortune that has befallen them.

There is always more than one way to view an event of course and another way of viewing the 9/11 tragedy is as a natural disaster. It may be a strange and difficult concept but the reality is that acts of terrorism obey the same laws of nature as other disasters, such as the recent tsunami. Analysis by Aaron Clauset and Maxwell Young of the University of New Mexico, Albuquerque has shown that world wide acts of terrorism follow the law of nature known as "power-law" relationship. Put simply the severity of an attack is inversely proportional to the time between attacks.

For those of a mathematical persuasion the ratio is x^-1.85.

Based on this approach we can expect another terrorist attack of the magnitude of 9/11 within the next 7 years.

If you are finding this concept somewhat difficult to accept then it may be that you are still thinking on the human race as being apart from nature and somehow not governed by its rules. Immanuel Kant was not burdened with this handicap. In 1784 he wrote

Individual men, and even whole nations, little think, while they are pursuing their own purposes...that they are advancing unconsciously under the guidance of a purpose of nature which is unknown to them.

This arises because we are talking of a sample of 6 billion individual organisms and the vagaries of small sample sizes simply do not apply.

This does not mean that we should stop trying to prevent terrorist attacks, that is part of the dynamic and is factored into the seven year estimate. It does however place a different perspective of the rhetoric relating to "the war on terror" that has been serving so effectively to re-elect conservative governments in the west. It is not a war, to win or lose, but a natural process in which we are all participants.

Read more in Nature