Enrico Fermi

Never underestimate the joy people derive from hearing something they already know.

Oh, anything with a probability of less than 20%.

I remember my friend Johnny von Neumann used to say, 'with four parameters I can fit an elephant and with five I can make him wiggle his trunk.'

It does not say in the Bible that all laws of nature are expressible linearly!

Where is everybody? Humans could theoretically colonize the galaxy in a million years or so, and if they could, astronauts from older civilizations could do the same. So why haven't They come to Earth?

When asked what characteristics Nobel prize winning physicists had in common I cannot think of a single one not even intelligence.

Never make anything more accurate than it needs to be.

Young man, if I could remember the names of these [muons, pions, etc.] particles, I would have been a botanist.

One might be led to question whether the scientists acted wisely in presenting the statesmen of the world with this appalling problem. Actually there was no choice. Once basic knowledge is acquired, any attempt at preventing its fruition would be as futile as hoping to stop the earth from revolving around the sun.

Ignorance is never better than knowledge.

It is not possible that such a small difference in the atomic weights of hydrogen and helium could have such tremendous consequences.

I hope it works.

The world has been changed, for good or ill.

The bomb will never go off, and I speak as an expert in explosives.

It is not good to be the only intelligent man in the world.

Before the test, I was nervous and had a very bad night. But when I saw the explosion, I became very calm.

Don't ever do a calculation without knowing the answer.

The fundamental problem is that the world is not simple. It is complex, and we are trying to understand it with simple ideas.

I remember my first impression of the Trinity test. It was a terrifying spectacle.

It was a beautiful phenomenon, a terrifying spectacle, and a profound experience.