It is surely important that the differences between coma, deep sleep, being under anesthesia, on the one hand, and being alert on the other, all involve changes in the brain.

It is important to understand that while oxytocin may be the hub of the evolution of the social brain in mammals, it is part of a very complex system. Part of what it does is act in opposition to stress hormones, and in that sense release of oxytocin feels good - as stress hormones and anxiety do not feel good.

I am less attracted to guesses about what cannot be done, than about making progress on a problem.

Early studies of sleep and dreaming were crucially dependent on waking subjects up during sleep to find out whether they are dreaming or not. Using that strategy, it was found that when the eyes are rapidly moving (REM sleep) people are usually dreaming; when the eyes are not moving, there may be some mentation, but little in the way of visually rich dreams.

Knowing about the neurobiological and evolutionary basis for social behavior can soften the arrogance and self-righteousness that often attends discussions of morality. It may help us all to think a little more carefully and rationally.

If I want to know how we learn and remember and represent the world, I will go to psychology and neuroscience. If I want to know where values come from, I will go to evolutionary biology and neuroscience and psychology, just as Aristotle and Hume would have, were they alive.

Theorizing is of course essential to make progress in understanding, but theorizing in the absence of knowing available relevant facts is not very productive.