Exactly. Of course they're capable of it. That doesn't mean they will. They have a lot of incentives to behave badly, and there's no way to eliminate them all.
Even under our decidedly non-anarchic regime, people STILL find reasons to behave poorly. I can't imagine removing the disincentive of state punishment would benefit society very much.
Even under our decidedly non-anarchic regime, people STILL find reasons to behave poorly. I can't imagine removing the disincentive of state punishment would benefit society very much.