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Richard Feynman on knowledge versus understanding
by Teaching staff
Who is Richard Feynman?
Richard Feynman, born in 1918, was a theoretical physicist whose work in quantum mechanics earned him the 1965 Nobel Prize in Physics.
according to nobleprize.org, Feynman received a bachelor’s degree. In 1939 at the Massachusetts Institute of Technology and studied at Princeton University where he earned a Ph.D. In 1942. “He was a research assistant at Princeton University (1940-1941), professor of theoretical physics at Cornell University (1945-1950), and a visiting professor and later appointed professor of theoretical physics at the California Institute of Technology (1950-1959). “
Feynman’s legendary intelligence – often mentioned alongside Isaac Newton and Albert Einstein – extends far beyond the theory and application of science. Feynman was also known for his ability to explain complex concepts with clarity and humor. His innovative teaching methods, characterized by intelligence and deep understanding of basic principles, inspire teachers worldwide. Feynman’s legacy emphasizes the importance of curiosity, imagination, and critical thinking.
The following is an excerpt from a lecture entitled “The Value of Science” given in New York City in 1955 at a meeting of the National Science Teachers Association.
See also What is the Feynman technique?
“Newton’s ideas about space and time agreed with experiment very well, but in order to obtain the correct motion of the orbit of Mercury, which was a very small difference, the difference in the nature of the theory required was enormous. The reason is that Newton’s laws were very simple and very ideal, and It led to specific results. In order to get something that would lead to a slightly different result, it had to be completely different. When you make a new law, you can’t make something perfect; you have to have something else perfect. So The differences in philosophical ideas between Newton and Einstein’s theories of gravity are enormous.
What are these philosophies? These are really difficult ways to calculate the consequences quickly. Philosophy, sometimes called understanding the law, is simply a way in which a person keeps laws in mind in order to quickly guess the consequences. Some people have said, and this is true in cases like Maxwell’s equations, “Don’t bother with philosophy, don’t bother with anything of that kind, just guess the equations.” The problem is only to calculate the answers so that they agree with experience, and it is not necessary to have a philosophy, argument or words around the equation.
This is a good thing, in the sense that if you just guess the equation you are not doing yourself any harm, and your guess will be better. On the other hand, philosophy may help you guess. It’s very difficult to say. For those who insist that the only thing that matters is that theory agrees with experience, I like to imagine a discussion between a Mayan astronomer and his student. The Maya were able to calculate predictions with great accuracy, for example, eclipses, the position of the Moon in the sky, the position of Venus, etc. This was all done by calculation. They counted a certain number, subtracted some numbers, and so on. There was no discussion about what the moon was. There was no discussion even about the idea of it spreading. They just calculated the time at which the eclipse would occur, or the time at which the full moon would rise, etc.
This is a good thing, in the sense that if you just guess the equation you are not doing yourself any harm, and your guess will be better. On the other hand, philosophy may help you guess. It’s very difficult to say.
Feynman
Suppose a young man goes to an astronomer and says: I have an idea. Maybe these things are rotating, and there are rock-like balls out there, and we can calculate how they move in a completely different way than just counting the time that they appear in the sky. The astronomer says: “Yes, and how accurately can you predict an eclipse?” “I haven’t developed this thing much yet,” he says. Then the astronomer says: Well, we can calculate the eclipse more accurately than you can with your model, so you shouldn’t pay any attention to your idea because obviously the mathematical scheme is better.
There’s a very strong tendency, when someone comes up with an idea and says: Suppose the world is like this, for people to say: What would you get as an answer to such-and-such a problem? ‘I didn’t develop it enough,’ he says. They say, “Well, we’ve already developed it further, and we can get the answers very precisely.”
So, it is an issue whether we should worry about the philosophies behind the ideas or not. Another way to work, of course, is to guess new principles. In Einstein’s theory of gravitation, he guessed, in addition to all other principles, the principle that corresponds to the idea that forces are always proportional to masses. He guessed the principle that if you are in an accelerating car you cannot distinguish that from being in a gravitational field, and by adding this principle to all the others, he was able to deduce the correct laws of gravity.
One of the most important things in “guessing – calculating consequences – comparing with experience” is knowing when you are right. It is possible to know when you are on the right track before checking all the consequences. You can recognize the truth by its beauty and simplicity. It’s always easier when you’ve made a guess, and done two or three little calculations to make sure it’s not obviously wrong, to know it’s right. When you do it right, it’s obviously right – at least if you have any experience – because what usually happens is that there are more going out than coming in. Your guess is that it’s actually something very simple. If you can’t immediately see that it’s wrong, that it’s simpler than it was before, then it’s right.
Inexperienced people, crazy people, and their ilk make simple guesses, but you can immediately see they’re wrong, so it doesn’t count. Others, inexperienced students, make very complex guesses, and it seems as if everything is fine, but I know that is not true because the truth is always simpler than you thought. What we need is imagination, but imagination in a terrible straitjacket. We have to find a new vision of the world that must agree with everything that is known, but differ in its predictions somewhere, otherwise it will not be interesting. In this dispute, he must agree with nature.
Others, inexperienced students, make very complex guesses, and it seems as if everything is fine, but I know that is not true because the truth is always simpler than you thought.
Viman
If you can find any other view of the world that agrees with the full range of things already observed, but differs elsewhere, you have made a great discovery. It is almost, but not quite, impossible to find any theory that agrees with experiments in the entire range over which all theories have been examined, and yet gives different results in another range, even a theory that does not show different results to agree with nature. It is very difficult to think of a new idea. It takes a great imagination…”
Video copied courtesy of Reddit user Reltpid
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