You do not know anything until you have practiced.

If you don't like it, go somewhere else, to another universe where the rules are simpler.

My rule is, when you are unhappy, think about it. But when you're happy, don't. Why spoil it? You're probably happy for some ridiculous reason and you'd just spoil it to know it.

I don't have to be good because they think I'm going to be good.

There is no learning without having to pose a question. And a question requires doubt.

Experiment is the sole judge of the validity of any idea.

Observation, reason, and experiment make up what we call the scientific method.