This article is about humans as a species.
The most momentous thing in human life is the art of winning the soul to good or evil .- (pythagoras)
(War is a state of armed conflict between societies. It is generally characterized by extreme aggression.)
why do we go to war? The cost to human society is enormous, yet for all our intellectual development, we continue to wage war well into the 21st century.
If group violence has been around for a long time in human society then we ought to have evolved psychological adaptations to a warlike lifestyle.
humanity could bring about its own destruction
(Nuclear armageddon)
The Cold War may be over, but we're not out of the nuclear woods just quite yet. In fact, the worst is likely still to come. The most frightening aspect of nuclear weapons, aside from their awesome power, is that it's old technology. The Bomb was developed back in the 1940s for goodness sakes — and it's no small miracle that proliferation hasn't been worse. It'll only be a matter of time before nation states hell bent on becoming nuclear capable will do so (Iran and North Korea being the best current examples). Part of the problem is that we live in the information age where the blueprints for these things are readily available for anyone who wants them — including non-state actors.
(Global Ecophagy)
Affectionately known as the "grey goo" scenario, this nightmarish possibility was first described by Eric Drexler in his seminal 1986 book, Engines of Creation. The basic idea is that, either by accident or deliberate intent, self-replicating nanobots could convert the entire planet into a useless pile of mush. Drexler wrote:
"Plants" with "leaves" no more efficient than today's solar cells could out-compete real plants, crowding the biosphere with an inedible foliage.
I don't recall him saying that. I DO recall other's, alarmists who have very little grasp of the technology saying something like that. Drexler said that the likelyhood of 'grey goo' is less likely than your car going feral. Imagine your car, one night, breaking out of the garage and crashing fences and eating grass. Imagine your car browing leaves off trees.
NOT gonna happen? Right. Neither will nanobots be likely to do that either.
Why do humans war? It has to do with them vs us. Humans can only hold a certain number of "us" in their heads at one time. See monkeysphere for a good explanation of how that works.