Feynman Quotes

It was found [in the 1970s], unexpectedly and without anyone really having a concept for it, that the rules of perturbation theory can be changed in a way that makes relativistic quantum gravity inevitable rather than impossible. The change is made by replacing point particles by strings. Then Feynman graphs are replaced by Riemann surfaces, which are smooth - unlike the graphs, which have singularities at interaction vertices. The Riemann surfaces can degenerate to graphs in many different ways. In field theory, the interactions occur at the vertices of a Feynman graph. By contrast, in string theory, the interaction is encoded globally, in the topology of a Riemann surface, any small piece of which is like any other. This is reminiscent of how non-linearities are encoded globally in twistor theory. (Edward Witten)

Replacing particles by strings is a naive-sounding step, from which many other things follow. In fact, replacing Feynman graphs by Riemann surfaces has numerous consequences: 1. It eliminates the infinities from the theory. ...2. It greatly reduces the number of possible theories. ...3. It gives the first hint that string theory will change our notions of spacetime. Just as in QCD, so also in gravity, many of the interesting questions cannot be answered in perturbation theory. In string theory, to understand the nature of the Big Bang, or the quantum fate of a black hole, or the nature of the vacuum state that determines the properties of the elementary particles, requires information beyond perturbation theory... Perturbation theory is not everything. It is just the way the [string] theory was discovered.

Edward Witten

... I would rather have questions that I can't answer than answers that I can't question. (variation of a remark by Richard Feynman)

Max Tegmark

The story that Dick Feynman could open safes whose combinations had been forgotten by their owners is true.

Stanislaw Ulam

I wonder how Feynman would feel if he had to be talking to not just a few nuts of this kind but e. g. to 2,500 similar nuts who would be moreover described by the media as good scientists, if not the best ones in the world.;-) Good for him that he managed to die in time.

Luboš Motl

Feynman was not a theorist's theorist, but a physicist's physicist and a teacher's teacher. Feynman's theoretical concepts opened up research opportunities for experimenters, and his approach to physics dignified the role played by their work.

Valentine Telegdi

There are two kinds of geniuses: the ‘ordinary' and the ‘magicians.' an ordinary genius is a fellow whom you and I would be just as good as, if we were only many times better. There is no mystery as to how his mind works. Once we understand what they've done, we feel certain that we, too, could have done it. It is different with the magicians... Feynman is a magician of the highest caliber.

Mark Kac

Richard Feynman presciently stated... that ‘There's Plenty of Room at the Bottom'. ...within this vast room ... there will be a requirement for communication.

Stephen F Bush

[Richard Feynman] truly believed that if you couldn't explain something simply, you didn't understand it.

Leonard Susskind

My friend Richard Feynman said, "I don't know." I heard him say it several times.

Penn Jillette

It's a simple statement of fact. When Richard Feynman didn't know, he often worked harder than anyone else to find out, but while he didn't know, he said, "I don't know." (Penn Jillette)

There has never been just one best way to teach quantum mechanics. My goal is neither to sow nostalgia for the philosophically engaged style of Oppenheimer and Nordheim, nor to condemn the pragmatic approach of Fermi, Bethe and Feynman. It is rather to highlight the choices that physicists must always make when stepping into the classroom. Choices of topics to discuss and problems to assign reflect deeper decisions about the ideal type of physicist one seeks to train. Should the new generation be philosophically attuned, concerned with minute details of conceptual interpretation? Or should physicists hone their ability to calculate, pushing Heisenberg's and Schrödinger's equations into the service of ever more elaborate problems to solve and phenomena to analyse? Competing ideals have flourished under different pedagogical conditions.

David Kaiser

Feynman uses Dirac's notation to describe the quantum mechanics of stimulated emission... he applies that physics to... dye molecules... In this regard, Feynman could have predicted the existence of the tunable laser.

F. J. Duarte

Thirty-one years ago [1948], Dick Feynman told me about his "sum over histories" version of quantum mechanics. "The electron does anything it likes," he said. "It just goes in any direction at any speed, forward or backward in time, however it likes, and then you add up the amplitudes and it gives you the wave-function." I said to him, "You're crazy." But he wasn't.

Freeman Dyson

The Feynman [Problem-Solving] Algorithm: (1) Write down the problem. (2) Think real hard. (3) Write down the solution.

Murray Gell-Mann

[W]hat I had been missing... and what Feynman realized: physics is the ultimate intellectual adventure, the quest to understand the deepest mysteries of our Universe. ...[I]t makes us see more clearly, adding to the beauty and wonder of the world ...[T]he lens of physics adds more beauty to the world ...

Max Tegmark

Let there be light, says the Bible. All the firmaments of technology, all our computers and networks, are built with light, and of light, and for light, to hasten its spread around the world. Light glows on the telescom's periphery; it shines as its core; it illuminates its webs and its links. From Newton, Maxwell, and Einstein to Richard Feynman and Charles Townes, the more men have gazed at light, the more it turns out to be a phenomenon utterly different from anything else. And yet everything else - every atom and every molecula - is fraught with its oscillating intensity.

George Gilder

Richard Feynman became so exasperated [at the National Academy of Sciences] that he resigned his membership, saying that he saw no point in belonging to an organization that spent most of its time deciding who to let in.

Richard Feynman

Feynman uses Dirac's notation to describe the quantum mechanics of stimulated emission. ... He applies that physics to several physical systems, including dye molecules. ... In this regard, Feynman could have predicted the existence of the tunable laser. Furthermore, Feynman made accessible Dirac's quantum notation via his thought experiments on two-slit interference with electrons.

Richard Feynman

Feynman has no interest in scholastic arguments. He is concerned only with human problems. He has a deep respect for religion, because he sees it as helping people to behave well toward one another and to be brave in facing tragedy. He respects religion as an important part of human nature. He does not himself believe in God, but he has no wish to destroy other people's belief.

Richard Feynman

Architect of quantum theories, brash young group leader on the atomic bomb project, inventor of the ubiquitous Feynman diagram, ebullient bongo player and storyteller, Richard Phillips Feynman was the most brilliant, iconoclastic, and influential physicist of modern times. He took the half-made conceptions of waves and particles in the 1940s and shaped them into tools that ordinary physicists could use and understand. He had a lightning ability to see into the heart of the problems nature posed. (Richard Feynman)

Feynman was fond of saying that all of quantum mechanics can be gleaned from carefully thinking through the implications of this single experiment, so it's well worth discussing.

Richard Feynman

Feynman is becoming a real pain in the ass.

Richard Feynman

Several conversations that Feynman and I had involved the remarkable abilities of other physicists. In one of these conversations, I remarked to Feynman that I was impressed by Stephen Hawking's ability to do path integration in his head. "Ahh, that's not so great", Feynman replied. "It's much more interesting to come up with the technique like I did, rather than to be able to do the mechanics in your head." Feynman wasn't being immodest, he was quite right. The true secret to genius is in creativity, not in technical mechanics.

Richard Feynman

In 1948 John Archibald Wheeler, in a telephone conversation with his student Richard Feynman, proposed the delightful hypothesis that there is just one electron in the universe.

Brian Hayes (scientist)