Why Do Wealth and Peace Exist?

A friend asked this question, and I wrote an answer.

Wealth exists because we invented agriculture, which gave us year-round access to stores of food from which some people can exclude others. This is why poverty exists, too, incidentally. I see wealth and poverty as two aspects of the same thing: scarcity. Foraging societies (like the Hadza in Africa) don't have the artificial scarcity that we civilized folk have, because every individual (including even fairly small children) knows how to go out into the bush and get food, shelter, and friendship (the basics we all need for survival: they don't call this wealth; it is simply life).

Peace exists when depopulation (from disease, famine, or war) gives agricultural societies breathing space to grow their wealth without having to protect it from other people. I see peace and war as fundamentally the same thing, complementary expressions of agricultural demographics. When foraging societies settle down to live in villages and cities, they become more fertile (producing more people in less time: this is peace--e.g. the Ara Pacis in ancient Rome, with pictures of motherhood on it). More humans (the outcome of greater fertility) means we need more stuff (wealth). Since we are sedentary and can only get wealth by access to land that we own (fence and work extensively)--we have to go out of our native habitat (overcrowded and overworked as it is) and occupy other land (virgin land). Eventually, we encounter other people--and the outcome of that meeting becomes war (not just the feuds of individual hunters and clans, which transcend agricultural society, but the organized genocide that is civilized war: we don't want mere revenge or justice or whatever; we want your land, and its wealth). 

Mercantilism and colonialism (or in their latest guise, globalization) allow us to enjoy peace and war, poverty and wealth, simultaneously. I send troops to Peter's land to take it or its wealth for me, and then sell that wealth on a "free" market to Paul, who has no idea that his diamonds come from the death of child-soldiers abroad. Poverty and war are outsourced to the frontier of civilization, so that the rich urban center can enjoy wealth and peace. To quote one of my favorite historians on the essence of peace: Auferre, trucidare, rapere falsis nominibus imperium; atque, ubi solitudinem faciunt, pacem appellant.  

In sum: wealth and peace exist because somewhere someone died (often miserably and involuntarily, sometimes voluntarily or otherwise nobly).