Parents provide their children with genes as well as an environment, so the fact that talkative parents have kids with good language skills could simply mean that and that the same genes that make parents talkative make children articulate.

With violence, as with so many other concerns, human nature is the problem, but human nature is also the solution.

Being smarter gives you a tailwind throughout life. People who are more intelligent earn more, live longer, get divorced less, are less likely to get addicted to alcohol and tobacco, and their children live longer.

Perhaps the most extraordinary popular delusion about violence of the past quarter-century is that it is caused by low self-esteem. That theory has been endorsed by dozens of prominent experts, has inspired school programs designed to get kids to feel better about themselves, and in the late 1980s led the California legislature to form a Task Force to Promote Self-Esteem. Yet Baumeister has shown that the theory could not be more spectacularly, hilariously, achingly wrong. Violence is a problem not of too little self-esteem but of too much, particularly when it is unearned.

In fact, without a specification of a creature's goals, the very idea of intelligence is meaningless. A toadstool could be given a genius award for accomplishing with pinpoint precision and unerring reliability, the feat of sitting exactly where it is sitting. Nothing would prevent us from agreeing with the cognitive scientist Zenon Pylyshyn that rocks are smarter than cats because rocks have the sense to go away when you kick them.

I don't think aggression works like thirst or sleep. I think aggression is more elicited by particular situations. I think it can be mitigated.

Why are empirical questions about how the mind works so weighted down with political and moral and emotional baggage?