Echoes of History

How do I model excellence?  I’ve been reading some ideas on how to model the performance of successful people and wanted to translate this into scientific discovery and physics.  If I want to model the physics discovery capabilities of one of the greats—Einstein, Newton, Noether, Fermi, Meitner, etc.—how exactly do I do that?  My natural response was to read biographies and historical analyses of how the discoverers made their discoveries.  My thinking was that by reading enough of these biographies I could distill contexts, triggers, events, habits that could be molded into modern practices.  But who to start with?  Maybe be biased by childhood serendipity and pick Newton or Einstein?  Or pick a neutrino pioneer like Pontecorvo or Pauli?  And then it occurred to me to just ask Google: “famous physicists’ ideas on discovery”.

It turns out Google AI came up with a pretty good answer, given by Feynman himself.

Richard P. Feynman is a well-known historical physicist who, in 1965, won the Nobel Prize in Physics among other things.  Feynman is a famous figure in the annals of scientific discovery, almost as famous as Einstein (though Einstein has figurines and action-figures while Feynman does not).  Like Einstein, Feynman was equally generous in communicating his insights and methods to his colleagues and the public at large.

In 1964, Feynman gave a series of seven public lectures at Cornell University, taped by the BBC and published as transcripts, “On the Character of Physical Law.”  The seventh lecture is titled “Seeking New Laws” which opens:

“What I want to talk about in this lecture is…what we think we know, what there is to guess, and how one goes about guessing.  Someone suggested that it would be ideal if, as I went along, I would slowly explain how to guess a law, and then end by creating a new law for you.  I do not know whether I shall be able to do that.”

(Feynman, “Seeking New Laws”, p. 1)

Upon reading this I felt as if the Google search bar had become a magic lamp and granted me my first wish: an interview with a physicist who knows how to discover things and where he gives advice about how to discover things!

Feynman suggests that to look for a new law, “First we guess it” (p. 156).  Then you calculate the result of the mathematical translation of the law and compare it to experiment.  Now guessing as adeptly as Feynman did, without guidance, is a bit intimidating, but luckily he goes on:

“Because I am a theoretical physicist…I want to now concentrate on how you make the guesses.  As I said before, it is not of any importance where the guess comes from; it is only important that it should agree with experiment, and that it should be as definite as possible…[One might think that] guessing is a dumb man’s job.  Actually it is quite the opposite, and I will try to explain why.  The first problem is how to start.”

(Feynman, “Seeking New Laws”, p.160)

Two pages later Feynman offers some practical advice on how, precisely, to start:

“One way you might suggest is to look at history to see how the other guys did it.  So we look at history.  We must start with Newton.”

(Feynman, “Seeking New Laws”, p.162)

Now at this point I’m delighted, Feynman thought of this historical digging idea too!  So the approach seems less frivolous now and I don’t feel so guilty for Googling; even Feynman might have tried it.  In fact, Feynman goes on to summarize his perception of the approaches used at five key turning points in physics history, which I’ll swiftly recap here (p. 162-163, P. 170):

1. Newton—guess a deeper law by cobbling together mathematical ideas close to experimentally observed data
2. Maxwell/Special Relativity—guess a deeper law by cobbling together mathematical ideas that other people have devised, see where they disagree, and invent whatever it takes to make them all agree
3. Quantum Mechanics—guess the right equation and make it ruthlessly accountable to measurement
4. Weak Particle Decays—guess the right equation and be willing to challenge the contradictory experimental evidence
5. Einstein—guess a new principle and add it to the known ones

But now that we’ve mined history, Feynman goes on to paradoxically conclude that:

“I am sure that history does not repeat itself in physics…  The reason is this.  Any schemes – such as ‘think of symmetry laws’, or ‘put the information in mathematical form’, or ‘guess equations’ – are known to everybody now, and they are all tried all the time.  When you are stuck, the answer cannot be one of these, because you will have tried these right away.  There must be another way next time.  Each time we get into this log-jam of too much trouble, too many problems, it is because the methods that we are using are just like the ones we have used before.  The next scheme, the new discovery, is going to be made in a completely different way.  So history does not help us much.”

(Feynman, “Seeking New Laws”, p. 163-164)

At which point I’m plunged into annoyance: Feynman thinks the only way to discover something new, is to discover something new to make new discoveries with!

After Feynman throws out this chicken-and-egg type paradox about how to discover something new, his  exact ideas get tricky and paraphrasing fails to do justice to the direction the rest of his lecture takes (the original transcript is worth a read).  But from a practice point of view, my previous numbered list drives home Feynman’s echoing refrain: guess.  That leaves two questions (1) how to guess and (2) how to evaluate if a guess is any good, assuming you ignore the historical options in the list above as Feynman suggests will be necessary.

According to Feynman, “You can have as much junk in the guess as you like, provided that the consequences can be compared with experiment” (p.164).  He goes on to suggest that sometimes the guess will revolve around deciding to keep some assumptions and throw others out.  He also suggests that having multiple theories or representations for the same outcome can help:

“By putting the theory in a certain kind of framework you get an idea of what to change…[If you have two theories A and B,] although they are identical before they are changed, there are certain ways of changing one which looks natural which will not look natural in the other.“

(Feynman, “Seeking New Laws”, p.168).

He also seems to weigh in against ad hoc add-on guesses:

“For instance, Newton’s ideas about space and time agreed with experiment very well, but in order to get the correct motion of the orbit of mercury…the difference in the character of the theory needed was enormous [i.e., you needed Einstein’s general relativity].  The reason is that Newton’s laws were so simple and so perfect…In order to get something that would produce a slightly different result it had to be completely different.  In stating a new law you cannot make imperfections on a perfect thing; you have to have another perfect thing.”

(Feynman, “Seeking New Laws”, p.169).

So, no tweaking, fudging, or knob turning allowed.  Lastly, Feynman discusses how to evaluate if a scientific guess is good or bad:

“It is always easy when you have made a guess, and done two or three little calculations to make sure that it is not obviously wrong, to know that it is right.  When you get it right, it is obvious that it is right – at least if you have any experience – because usually what happens is that more comes out than goes in.”

(Feynman, “Seeking New Laws”, p.171).

So, Feynman’s take on the mental work that goes into discovery is that it is a persistent, strategic, guessing game.  The only way to succeed is to keep guessing until you get it right by learning something new:

“We must, and we should, and we always do, extend as far as we can beyond what we already know, beyond those ideas that we have already obtained.  Dangerous?  Yes.  Uncertain?  Yes.  But it is the only way to make science useful.  Science is only useful if it tells you about some experiment that has not been done; it is no good if it only tells you what just went on.  It is necessary to extend the ideas beyond where they have been tested.”

(Feynman, “Seeking New Laws”, p.164).

So that’s the pursuit of discovery as our friend Feynman sees it: if at first you don’t succeed, guess, then guess again.  It’s often hard when mining the echoes of history to know which conversations to shout forward and which to let fade out.  It’s also rare that I quote so much from one voice.  But as advice from one insightful scientist to future generations, Feynman’s reflections on the art of scientific discovery are still a conversation worth hearing.