Thread by @arjunkhemani

The Meaning of It All by Richard Feynman; a summary:

Richard P. Feynman was one of the 20th century's most brilliant theoretical physicists and original thinkers. He all but rebuilt the theory of quantum electrodynamics. It was for this work that he shared the Nobel Prize in 1965.

"I have to understand the world, you see."

— Richard P. Feynman

Of course, Feynman is also famous for another reason: his practical jokes and jovial childlike character, revealed in stories and books like the famous collection of anecdotes Surely You’re Joking, Mr. Feynman!

The Meaning of It All is a collection of three public lectures Feynman gave to a lay audience at the University of Washington, Seattle, in April 1963. These lectures are timeless and their message critical for both science and society. Here is my summary of its first lecture:

In his first lecture, "The Uncertainty of Science", Feynman explains the nature of science. He points out that we shouldn't be too precise in defining words:

"A great deal has been made of this by philosophers, who say that words must be defined extremely precisely. Actually, I disagree with this; I think that extreme precision of definition is often not worthwhile, and sometimes it is not possible—in fact mostly it is not possible."

Feynman explains that science is a special method of "finding things out". Three aspects of science are then discussed.

1. The most observable characteristic of science is its application, the fact that as a consequence of science, one has the power to do things. But this power to do things carries with it no instructions on how to use it, whether to use it for good or evil.

2. The next aspect of science is its contents, the things found out. All the disciplined thinking and hard work is for this end. It is not for the sake of an application but for the excitement of what one discovers. Scientists seek good explanations for their own sake.

3. The third aspect, which I consider most important—is science as a method of finding things out. This method relies on observation as the judge of whether something is true. But "true" used in this way really means "not falsified".

(Contd.) In science, the exception tests the rule. Or, put another way, the exception proves the rule wrong (given, of course, that there is nothing wrong with the experimental conditions). That is the principle of science. Its objective is not to prove but to test theories.

"The scientist tries to find more exceptions and to determine the characteristics of the exceptions, a process that is continually exciting as it develops...

He does not try to avoid showing that the rules are wrong; there is progress and excitement in the exact opposite. He tries to prove himself wrong as quickly as possible."

Feynman further explains that the fact that something is not scientific (i.e., not testable) is not that it is wrong or stupid. It means just that. It is not scientific.

The importance of the explanatory content of a scientific theory is then stressed.

"...the more specific a rule is, the more interesting it is. The more definite the statement, the more interesting it is to test."

We can use an example to illustrate this point. If I propose a theory such as "It will rain," then I have made a somewhat empty and uninteresting claim. All sorts of questions of specificity arise. Where will it rain? When will it rain? How much will it rain?

My claim lacks explanatory content. It does not explain anything. Hence, it is automatically uninteresting to test.

However, if I propose my theory of the weather tomorrow as "It will rain between half a centimeter and a centimeter at 2:00 PM in Southern Mumbai due to moisture-laden air from the Indian Ocean," then I have made a hard-to-vary claim that is scientifically interesting to test.

The more specific the theory, the more powerful it is, the more liable it is to exceptions, and the more exciting and valuable it is to check.

Then Feynman speaks of the sources of ideas. People used to believe that the job of science was to make many observations and that those observations would themselves suggest the laws. But it does not work that way. As Feynman says, "It takes much more imagination than that."

"So the next thing we have to talk about is where the new ideas come from. Actually, it does not make any difference, as long as they come...

We have a way of checking whether an idea is correct or not that has nothing to do with where it came from. We simply test it against observation. So in science we are not interested in where an idea comes from."

There is no authority who decides what is a good idea. The old laws may be wrong. But how can an observation be incorrect? If it has been carefully checked, how can it be wrong? Why are physicists constantly having to change the laws?

Feynman explains this is because "first, the laws are not the observations and, second, that experiments are always inaccurate... You do not know what is going to happen, so you take a guess."

Feynman embraces the conjectural nature of all explanations and theories.

"It is necessary and true that all of the things we say in science, all of the conclusions, are uncertain, because they are only conclusions."

Scientists, therefore, are used to dealing with doubt and uncertainty. All scientific knowledge is uncertain.

Feynman explains this experience with doubt and uncertainty is of great value, and he believes one that extends beyond the sciences.

"I believe that to solve any problem that has never been solved before, you have to leave the door to the unknown ajar. You have to permit the possibility that you do not have it exactly right. Otherwise, if you have made up your mind already, you might not solve it."

"If we were not able or did not desire to look in any new direction, if we did not have a doubt or recognize ignorance, we would not get any new ideas. There would be nothing worth checking, because we would know what is true."

Feynman doesn't want us to forget the importance of the struggle that permitted this freedom to doubt.

"I feel a responsibility to proclaim the value of this freedom and to teach that doubt is not to be feared, but that it is to be welcomed as the possibility of a new potential for human beings. If you know that you are not sure, you have a chance to improve the situation."

Let me know if you would like me to post my summary of Feynman's second lecture in this collection "The Uncertainty of Values".

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