In honor of his centennial, the Top 10 Feynman quotations

Famous physicist speaks from the grave with wisdom, insight and advice

Richard Feynman

Richard Feynman offered insights on the nature of reality, science and technological progress — as well as on human nature.

Tamiko Thiel/WikiCommons (CC BY-SA 3.0)

As Richard Feynman once said, “a man cannot live beyond the grave,” and so surely Feynman could not speak from the grave, either. Except that actually, he did.

For years after his death in 1988, books appeared with collections of Feynman’s articles, talks and other miscellaneous writings. Together with his two autobiographical books and his famous lectures on physics, those works offer an enormous corpus of wisdom, advice, opinion and insight into nature, science, life and society. His words are widely quoted, and in fact his most noteworthy quotations fill up a fat book edited by his daughter Michelle, The Quotable Feynman (Princeton University Press, 2015).

You could read that whole book if you like, of course. But if you’re short on time, you could just peruse the Top 10 Feynman Quotes below, selected from his works to commemorate the 100th anniversary of Feynman’s birth on May 11. (At least they’re my favorite 10. He might have ranked them differently.)

10. “If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis … that all things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another.”

From the famous Feynman Lectures on Physics, this statement exemplifies Feynman’s gift for distilling the essence from complicated science and expressing it colloquially. His words really ought to be inscribed somewhere in a permanent form, just in case.

9. “There is nothing that living things do that cannot be understood from the point of view that they are made of atoms acting according to the laws of physics.”

A further expression of the importance of atoms from the opening pages of Feynman’s lectures. If anyone still disagrees with this sentiment, they should watch Westworld.

8. “For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.”

This statement was Feynman’s succinct way of telling NASA to clean up its act after the explosion of the space shuttle Challenger in 1986.

7. “From my knowledge of the world that I see around me, I think that it is much more likely that the reports of flying saucers are the results of the known irrational characteristics of terrestrial intelligence than of the unknown rational efforts of extra-terrestrial intelligence.”

In a set of lectures compiled in book form as The Character of Physical Law, Feynman discussed scientific exploration as not seeking certainty, or proving some things impossible, but identifying what is probable. Flying saucers are possible, but are not therefore likely to exist; they are much more probably figments of overactive human imaginations (or deliberate attempts at deception).

6. “Most likely anything that you think of that is possible isn’t true. In fact that’s a general principle in physics theories: no matter what a guy thinks of, it’s almost always false.”

From another series of lectures, compiled as The Meaning of It All, in which Feynman expanded on the probabilistic nature of scientific knowledge. Many more things are possible than reality can accommodate; statistically, therefore, most possibilities are actually not true. That explains why so much that so many people say is so wrong.

5. “What is necessary ‘for the very existence of science,’ and what the characteristics of nature are, are not to be determined by pompous preconditions, they are determined always by the material with which we work, by nature herself.”

Also from The Character of Physical Law, this Feynman sentiment should remind scientists blinded by philosophical predispositions that defining “science” is not up to people, whether lexicographers or philosophers. Nature writes the rules. Science is the process of finding out what its own rules need to be to decipher the rules for the universe that nature has written.

4. “There’s plenty of room at the bottom.”

This simple statement was the title of a talk Feynman delivered in 1959, widely regarded today as the original inspiration for the origin of nanoscience and nanotechnology. Feynman recognized that miniaturization in recording information was limited only by the size of atoms, and he even imagined that atoms could someday be manipulated individually. And they have been.

3. “Nature isn’t classical, dammit, and if you want to make a simulation of nature, you’d better make it quantum mechanical.”

Feynman wasn’t the first to consider the idea of a quantum computer, but his words (from a 1981 talk, published in 1982) inspired some physicists to take the idea seriously. Feynman had no idea how to actually build a quantum computer, and serious work on real designs didn’t begin until the late 1990s. Today’s primitive versions of quantum computers can solve some simple problems and may soon be able to outperform standard computers on some types of problems, many experts believe. And perhaps such computers will, in fact, be able to simulate how nature works. (By the way, this statement is misquoted in The Quotable Feynman. As Feynman would have advised, always check things out for yourself.)

2. “I think I can safely say that nobody understands quantum mechanics.”

As Feynman said in The Character of Physical Law, many people understand other sophisticated physical theories, including Einstein’s relativity. But quantum mechanics resists an equivalent depth of understanding. Some disagree, proclaiming that they understand quantum mechanics perfectly well. But their understanding disagrees with the supposed understanding of others, equally knowledgeable. Perhaps Feynman’s sentiment might better be expressed by saying that anyone who claims to understand quantum mechanics, doesn’t.

1. “The first principle is that you must not fool yourself — and you are the easiest person to fool.”

The best Feynman quote of all (from a 1974 address), and the best advice to scientists and anybody else who seeks the truth about the world. The truth may not be what you’d like it to be, or what would be best for you, or what your preconceived philosophy tells you that it is. Unless you recognize how easily you can be fooled, you will be. 

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Tom Siegfried is a contributing correspondent. He was editor in chief of Science News from 2007 to 2012 and managing editor from 2014 to 2017.

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