[thelastguy]

>They don't act in their own self interests.

Actually, they do. For example, when a criminal steals, he's acting purely in his own interest. He doensn't care about anyone else's interests. He doesn't care about his victim's interest. He only care about his own interest. Which is why he steals. For his own self interest.

The problem is, society also has it's own interest. And it's in the best interest of society to jail the thief.

Anyway, I think you meant to say that criminal doesn't think about the consequences of their actions. Again, because everything criminals do are for their own self interest. Even doing something stupid like drugs, is for their own self interest (in this case, he does it because his interest is to feel high).