Richard Feynman

The first principle is that you must not fool yourself - and you are the easiest person to fool.

Physicists like to think that all you have to do is say, these are the conditions, now what happens next?

Nature has a great simplicity and therefore a great beauty.

Philosophers say a great deal about what is absolutely necessary for science, and it is always, so far as one can see, rather naive, and probably wrong.

For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.

I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.

I was born not knowing and have only had a little time to change that here and there.

I was born not knowing and have had only a little time to change that here and there.

There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.

The worthwhile problems are the ones you can really solve or help solve, the ones you can really contribute something to.

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

Physics is like sex: sure, it may give some practical results, but that's not why we do it.

Physics is to math what sex is to masturbation.

We are at the very beginning of time for the human race. It is not unreasonable that we grapple with problems. But there are tens of thousands of years in the future. Our responsibility is to do what we can, learn what we can, improve the solutions, and pass them on.

You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts. I learned very early the difference between knowing the name of something and knowing something.

No problem is too small or too trivial if we can really do something about it.