The proposition here is that the human brain is, in large part, a machine for winning arguments, a machine for convincing others that its owner is in the right—and thus a machine for convincing its owner of the same thing. The brain is like a good lawyer: given any set of interests to defend, it sets about convincing the world of their moral and logical worth, regardless of whether they in fact have any of either. Like a lawyer, the human brain wants victory, not truth; and, like a lawyer, it is sometimes more admirable for skill than for virtue.
Robert Wright, The Moral Animal