Howard spoke to Salon from his home in West Berkshire, England, about the historical origins of peace, America's controversial and significant role in the international community and the prospect of peace in our post-heroic age.

If peace was "invented," are you saying that man is in his more natural state when he is at war?

Conflict is a natural state at every level of human life. Peace involves, over many years, structures, organizations and laws which exist to manage that conflict. That is not a natural condition. That is something which develops only over long periods of time with a great deal of hard work and many back-slippings. Peace is not a natural state of society, any more than war is a natural state of society. Conflict is what is endemic and, if you like, is natural. There is only going to be peace if those conflicts can be managed and subsumed. That is what peacemaking is really all about.

What is the difference between positive and negative peace?

Negative peace can be defined as the absence of war, when people are not actually fighting one another. It doesn't indicate that they're not likely to start fighting one another at any moment; it may be just a brief interval between conflicts. But at the same time, they're not actually trying to kill one another. Positive peace is a situation in which there is not any probability of conflict, where people do not have to prepare for it or think about conflict, where there is a stable organization of society in which there's neither need nor inclination to resort to violence.

How do some of the conditions of peace turn into war?

During peacetime, conflicts boil up which eventually do explode into war. It is the nature of the structure of society during peacetime. For example, in Europe, between the two world wars there was peace. Nonetheless, there were intensive rivalries and hostilities. Even in a democratic structure such as Weimar Germany, extremist movements could come to power which either could not achieve their objectives without war or which genuinely looked forward to war as an agreeable occupation.

You say that the idea of peace was more or less invented by the Enlightenment thinkers.

Yes. It was taken for granted, certainly within European society, that war was natural and inevitable and that society was organized for war. The people in charge of societies were warriors or the descendants of warriors who really regarded it as their job to prepare for and, if possible, to win the wars which were going to happen. Peace was just the intervals between wars which were very largely taken up with preparing for the next war. The idea that society could be organized without war at all -- without the possibility or probability of war happening -- was something which only developed with the 18th century Enlightenment and became, increasingly, the accepted view of Western societies. It took quite a long time for it to get through.

But new ideologies glorifying war did develop after the Enlightenment, didn't they?

In the 19th and the early 20th century, you get the philosophy of social Darwinism -- the idea that conflict is inevitable between people and between peoples, and unless you strive for dominance, you are going to be dominated. That was very much the sense before and during the First World War: Either you conquer or you are conquered. Therefore, fighting was not only natural but necessary and desirable. Men -- and it is a masculine, male-dominated society -- found their finest fulfillment and justification in fighting. They believed that peace was a bad thing and that in peace people rotted, they became decadent and societies degenerated.

Maya Angelou reads from "The Heart of a Woman"