It is going to be necessary that everything that happens in a finite volume of space and time would have to be analyzable with a finite number of logical operations. The present theory of physics is not that way, apparently. It allows space to go down into infinitesimal distances, wavelengths to get infinitely great, terms to be summed in infinite order, and so forth; and therefore, if this proposition [that physics is computer-simulatable] is right, physical law is wrong.

When you get as old as I am, you start to realize that you've told most of the good stuff you know to other people anyway.

If you thought that science was certain - well, that is just an error on your part.

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

When a Caltech student asked the eminent cosmologist Michael Turner what his "bias" was in favoring one or another particle as a likely candidate to compromise dark matter in the universe, Feynmann snapped, "Why do you want to know his bias? Form your own bias!"

I love only nature, and I hate mathematicians.

Why make yourself miserable saying things like, "Why do we have such bad luck? What has God done to us? What have we done to deserve this?" - all of which, if you understand reality and take it completely into your heart, are irrelevant and unsolvable. They are just things that nobody can know. Your situation is just an accident of life.