Anarchy, according to Merriam Webster, is "a utopian society of individuals who enjoy complete freedom without government." My libertarian friends, who rightly call for a reduction of the federal leviathan, go to far when they advocate it's death.
Liberty unconstrained is no liberty at all. Why? Because if everyone does whatever they want, then only one rule applies. The law of the jungle. Those who can, will rape and pillage, and no individual can stop them.
The solution is to form pacts with your fellow man in order to protect each other from the aggression of others. By doing this, you voluntarily trade liberty for security. And you do this freely, because like any transaction in a free market, you value what you get more than what you give.
These associations of mutual protection, known as government, are the free market's solution to the problem of human nature. Real liberty lies somewhere in the middle of no government and too much.