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.

Remember, in the heyday of vitalism, people said that when all the data are in about cells and how they work, we will still know nothing about the life force - about the basic difference between being alive and not being alive.

Humility bids us to take ourselves as we are; we do not have to be cosmically significant to be genuinely significant.

When that theory is isolated from known facts, it is likely not to be productive.

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.

It seems probable that humans have been on the planet, with much the same brain, for about 250,000 years.

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