In general we look for a new law by the following process. First we guess it. Then we compute the consequences of the guess to see what would be implied if this law that we guessed is right. Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what his name is

We've learned from experience that the truth will come out. Other experimenters will repeat your experiment and find out whether you were wrong or right. Nature's phenomena will agree or they'll disagree with your theory. And, although you may gain some temporary fame and excitement, you will not gain a good reputation as a scientist if you haven't tried to be very careful in this kind of work. And it's this type of integrity, this kind of care not to fool yourself, that is missing to a large extent in much of the research in cargo cult science.

That is all there is to it. No doubts, no discussion of earlier affairs, no to-ing and fro-ing, no physical experiment beyond a kiss, none of the complex voodoo which is thought necessary in even the most perfunctory modern novel to clap two ninnies together.

When we’re dancing, the struggle is gone.

An instinct is an urge inherent in organic life to restore an earlier state of things

We know less about the sexual life of little girls than of boys. But we need not feel ashamed of this distinction; after all, the sexual life of adult women is a 'dark continent' for psychology.

Meditation on the chance which led to the meeting of my mother and father is even more salutary than meditation on death.

No human being escapes the necessity of conceiving some good outside himself towards which his thought turns in a movement of desire, supplication, and hope. consequently, the only choice is between worshipping the true God or an idol. Every atheist is an idolater — unless he is worshipping the true God in his impersonal aspect. The majority of the pious are idolaters.

Very few people, including authors willing to commit to paper, ever really read primary sources—certainly not in necessary depth and comtemplation, and often not at all… When writers close themselves off to the documents of scholarship, and then rely only on seeing or asking, they become conduits and sieves rather than thinkers. When, on the other hand, you study the great works of predecessors engaged in the same struggle, you enter a dialogue with human history and the rich variety of our own intellectual traditions. You insert yourself, and your own organizing powers, into this history—and you become an acive agent, not merely a reporter.

Wallace's error on human intellect arose from the inadequacy of his rigid selectionism, not from a failure to apply it. And his argument repays our study today, since its flaw persists as the weak link in many of the most modern evolutionary speculations of our current literature. For Wallace's rigid selectionism is much closer than Darwin's pluralism to the attitude embodied in our favored theory today, which, ironically in this context, goes by the name of Neo-Darwinism.

On seeing the Enterprise's warp engine while visiting the set of Star Trek: The Next Generation (where he would briefly play himself in the 1993 episode Descent, Part I), Hawking smiled and said: I'm working on that.

I guess the good news is that we didn't make any big mistakes in the design of earlier versions of Mathematica that we'd have to go back on now.

The thing that got me started on the science that I've been building now for about 20 years or so was the question of okay, if mathematical equations can't make progress in understanding complex phenomena in the natural world, how might we make progress?

Ours is a government of liberty by, through, and under the law.

Our smile affirms our awareness and determination to live in peace and joy.

Clever men are good, but they are not the best.

I have often thought that if heaven had given me choice of my position and calling, it should have been on a rich spot of earth, well watered, and near a good market for the productions of the garden. No occupation is so delightful to me as the culture of the earth, and no culture comparable to that of the garden. Such a variety of subjects, someone always coming to perfection, the failure of one thing repaired by the success of another, and instead of one harvest, a continued one thro' the year. Under a total want of demand except for our family table. I am still devoted to the garden. But tho' an old man, I am but a young gardener.

I hope we shall crush in its birth the aristocracy of our moneyed corporations, which dare already to challenge our government to a trial of strength and bid defiance to the laws of our country.

No free man shall ever be de-barred the use of arms [within his own lands]. The strongest reason for the people to retain their right to keep and bear arms is as a last resort to protect themselves against tyranny in government.

After the conversations about Indian philosophy, some of the ideas of Quantum Physics that had seemed so crazy suddenly made much more sense.