The tendency to be rational is the consistent and hence predictable element in human behavior. (p.4) - David D. Friedman

An ideal objectivist society with a limited government is superior to an anarcho-capitalist society in precisely the same way that an ideal socialist society is superior to a capitalist society. Socialism does better with perfect people than anarcho-capitalism with imperfect. And it is better to wear a bikini with the sun shining than a raincoat when it is raining. That is no argument against carrying an umbrella. (p.134)

I predict that, if anarcho-capitalist institutions appeared in this country tomorrow, heroin would be legal in New York and illegal in most other places. (p.128)

Economics is that way of understanding behavior that starts from the assumption that people have objectives and tend to choose the correct way to achieve them.