I think that a lot of social movements, political movements, powerful ones - certainly they form, collectively, an idea of the truth which becomes hard to question. It becomes a dogma, and from the inside it starts to look like common sense.

Science works because the phenomenon being described can be relied on to remain the same. Even in quantum physics, where phenomena are changed by observation, the way in which observation interferes is regular and falls within a limited range of possibilities. Human culture, however, has the nasty habit of never staying the same for very long.

Being virtuous is wonderful thing, but feeling virtuous is a shortcut to vice.

The idea that the mind can extend even beyond the body is an intriguing one, and is bound to become more pressing as we increasingly develop technologies that augment our natural abilities.

Progress is more of a challenge for the cynic but also more important and urgent, since for the optimist things aren't that bad and are bound to get better anyway.

There are many things you shouldn't measure. Don't, for example, try to measure how much you love your wife!

Whatever your religious persuasion, if you believe that the universe is governed by benign forces, at some point you have to explain why there is so much suffering, misfortune and misery in the world.