Richard Feynman on knowing and understanding
go through Teach ideological personnel
Who is Richard Feynman?
Richard Feynman (born 1918) was a theoretical physicist whose work in quantum mechanics earned him the 1965 Nobel Prize in Physics.
According to Nobelprize.org, Feynman received his B.A. at MIT in 1939 and at Princeton University, where he received his Ph.D. in 1942. “He served as a research assistant at Princeton University (1940-1941), professor of theoretical physics at Cornell University (1945-1950), visiting professor, and later was appointed professor of theoretical physics at Caltech (1950-1959).”
Feynman’s legendary wisdom – often mentioned alongside Isaac Newton and Albert Einstein – transcended the theory and practice of science. Feynman was also known for his ability to explain complex concepts with clarity and humor. His innovative teaching methods, characterized by wisdom and a deep understanding of fundamental principles, inspire educators around the world. Feynman’s legacy emphasized the importance of curiosity, imagination, and critical thinking.
The following is an excerpt from a speech entitled “The Value of Science” given at the National Science Teachers Association conference in New York City in 1955.
See What is the Feynman Technique?
“Newton’s ideas about space and time agreed very well with experiment, but in order to get the correct motion of Mercury’s orbit, which was a very, very small difference, the difference in the characteristics of the theory required was huge. The reason is that Newton’s laws were so simple and perfect, and they produced definite results. In order to get something that would produce slightly different results, it had to be completely different. In stating a new law, you can’t make an imperfection in a perfect thing; you have to have another perfect thing. So the difference in philosophical thought between Newton’s and Einstein’s theories of gravity is huge.
What are these philosophies? They are really tricky ways to calculate consequences quickly. Philosophy is sometimes called the understanding of the law, it is simply a way for a person to keep the law in mind in order to quickly guess the consequences. Some people have said, and this is true in cases like Maxwell’s equations, “Never mind philosophy, never mind any such thing, just guess at the equations.” The problem is simply to compute the answers so that they agree with experiments, and there need be no philosophy, arguments, or writing about the equations. “
This is good in the sense that if you just guess the equation, you won’t bias yourself and you will guess better. On the other hand, maybe this philosophy can help you guess. It’s hard to say. For those who insist that the only thing that matters is that theory matches experiment, I would like to imagine a discussion between a Mayan astronomer and his students. The Mayans were able to calculate predictions with great accuracy, such as solar eclipses, the position of the moon in the sky, the position of Venus, etc. This is all done through arithmetic. They counted a number and subtracted some, and so on. There is no discussion of what the moon is. The idea of it spreading wasn’t even discussed. They just figured out when a solar eclipse would happen, or when the moon would rise, and so on.
This is good in the sense that if you just guess the equation, you won’t bias yourself and you will guess better. On the other hand, maybe this philosophy can help you guess. It’s hard to say.
Feynman
Suppose a young man goes to an astronomer and says: ‘I have an idea. Maybe these things are moving around, and there are some rock-like spheres out there, and we can calculate how they move in a completely different way, rather than just calculating the time they appear in the sky. “Yes,” said the astronomer, “can you accurately predict a solar eclipse?” “I haven’t gotten very far with this yet,” he said. Then the astronomers said, “Well, we can calculate eclipses more accurately than you can with your model, so you don’t have to focus on what you think, because obviously the math scheme is better”.
There is a very strong tendency, when someone comes up with an idea and says, “Let’s suppose the world is like this,” and people say to him, “What answer would you get to such and such a question?” He says, “I haven’t developed it far enough.” They said, ‘Well, we’ve developed it further and we can get the answer very accurately’.
So whether to worry about the philosophy behind the ideas is a question. Of course, another way of working is to guess at new principles. In Einstein’s theory of gravity, among all other principles, he speculated on a principle corresponding to the idea that force is always proportional to mass. He guessed at the principle that if you were in an accelerating car, you couldn’t tell it apart from being in a gravitational field, and by adding that principle to all the other principles, he was able to derive the correct law of gravity.
One of the most important things in this “guess – calculate – compare with experiment” business is knowing when you are right. You can tell when you’re right before you examine all the consequences. You can know truth by its beauty and simplicity. It’s always easy when you make a guess and do two or three small calculations to make sure it’s not obviously wrong and know it’s correct. When you get it right, it’s obvious it’s right – at least if you have any experience – because what usually happens is more comes out than goes in. In fact, your guess is, something is pretty simple. If you can’t immediately see that it’s wrong and it’s simpler than before, then it’s right.
Inexperienced people, lunatics and the like make simple guesses, but you can tell right away they’re wrong, so they don’t count. Others, inexperienced students, make complicated guesses that may seem okay, but I know it’s not true because the truth is always simpler than you think. What we need is imagination, but imagination wears a terrible straitjacket. We have to find a new worldview that is consistent with everything known but in some places different from what it predicts, otherwise it’s not interesting. In this disagreement it must conform to nature.
Others, inexperienced students, make complicated guesses that may seem okay, but I know it’s not true because the truth is always simpler than you think.
Feynman
If you can find any other worldview that agrees across the entire range of things that have been observed, but disagrees elsewhere, then you have made a great discovery. It is almost impossible (but not entirely) to find any theory that agrees with experiment over the entire range in which all theories are tested, but gives different results in other ranges, even a theory whose different results are inconsistent with nature. A new idea is extremely difficult to come up with. This requires a lot of imagination…”
Video transcription provided by Reddit user Reltpid
