I think it's much more interesting to live not knowing than to have answers which might be wrong. I have approximate answers, and possible beliefs, and different degrees of uncertainty about different things, but I am not absolutely sure of anything. There are many things I don't know anything about, such as whether it means anything to ask "Why are we here?" I might think about it a little bit, and if I can't figure it out then I go on to something else. But I don't have to know an answer. I don't feel frightened by not knowing things, by being lost in the mysterious universe without having any purpose - which is the way it really is, as far as I can tell.

Ordinarily it would take me about fifteen minutes to get a hallucination going," wrote Feynman, "but on a few occasions, when I smoked some marijuana beforehand, it came very quickly.

Work as hard and as much as you want to on the things you like to do the best.

The whole question of imagination in science is often misunderstood by people in other disciplines. ... They overlook the fact that whatever we are allowed to imagine in science must be consistent with everything else we know.

Know your place in the world and evaluate yourself fairly, not in terms of the naïve ideals of your own youth, nor in terms of what you erroneously imagine your teacher's ideals are.

We find that the statements of science are not of what is true and what is not true, but statements of what is known with different degrees of certainty: "It is very much more likely that so and so is true than that it is not true".

There is no harm in doubt and skepticism, for it is through these that new discoveries are made.