The indispensability of reason does not imply that individual people are always rational or are unswayed by passion and illusion. It only means that people are capable of reason, and that a community of people who choose to perfect this faculty and to exercise it openly and fairly can collectively reason their way to sounder conclusions in the long run. As Lincoln observed, you can fool all of the people some of the time, and you can fool some of the people all of the time, but you can't fool all of the people all of the time.

You know that when Irving puts the dog in the car, it is no longer in the yard. When Edna goes to church, her head goes with her. If Doug is in the house, he must have gone through some opening unless he was born there and never left. If Sheila is alive at 9 A.M. and is alive at 5 P.M., she was also alive at noon. Zebras in the wild never wear underwear. Opening a jar of a new brand of peanut butter will not vaporize the house. People never shove meat thermometers in their ears. A gerbil is smaller than Mt. Kilimanjaro.

Reason is non-negotiable. Try to argue against it, or to exclude it from some realm of knowledge, and you've already lost the argument, because you're using reason to make your case. ... We don't "believe" in reason.

What is true for the emotions may also be true for the intellect. Some of our perplexities may come from a mismatch between the purposes for which our cognitive faculties evolved and the purposes to which we put them today.

There's a common criticism of evolutionary psychology that it's fatalistic and it dooms us to eternal strife, 'Why even try to work toward peace if we're just bloody killer apes and violence is in our genes?'

Of course genes can’t pull the levers of our behavior directly. But they affect the wiring and workings of the brain, and the brain is the seat of our drives, temperaments and patterns of thought. Each of us is dealt a unique hand of tastes and aptitudes, like curiosity, ambition, empathy, a thirst for novelty or for security, a comfort level with the social or the mechanical or the abstract. Some opportunities we come across click with our constitutions and set us along a path in life.

We really are creatures of a violent world, biologically speaking - watching violence and learning about it is one of our cognitive drives.