Today is Ed Witten’s birthday, apparently. I recently completed S. Weinberg’s book “To Explain the World”, so I will instead collect some excerpts from that book here. Let’s start with one from near the beginning of the book.
There remains a poetic element in modern physics. We do not write in poetry; much of the writing of physicists barely reaches the level of prose. But we seek beauty in our theories, and use aesthetic judgments as a guide in our research.
I like the phrase “barely reaches the level of prose”. It really made me laugh out loud, while reminding me of a quote by Francis Crick:
There is no form of prose more difficult to understand and more tedious to read than the average scientific paper.
There will be seen [in this book] demonstrations of those kinds which do not produce as great a certitude as those of Geometry, and which differ much therefrom, since whereas the Geometers prove their Propositions by fixed and incontestable Principles, here the Principles are verified by the conclusions to be drawn from them; the nature of these things not allowing of this being done otherwise.
I like this “way of doing science” as it is how I think about theoretical physics research, especially high energy physics. Of course, the sentiment above is as valid for any theorist or experimentalist or phenomenologist or someone in-between. Because in my view, the phrase “⋯Principles are verified by the conclusions⋯” is so broad that the “conclusions” include everything from experimental results (Gedanken or physical or any other kind one could think of) to results in terms of equations (Abstract or useful or any other kind one could think of). This broad view further enforced by the next phrase “⋯nature of these things not allowing of this being done otherwise”, puts into perspective that the “dated” view of scientific method (Hypothesis → Experiment → Confirmation? → Theory or Re-Hypothesize!) is indeed “dated”. The scientific method should instead be thought of as “Principles → ??? → Consequences”. [A better discussion along similar lines can be found here.] The “???” could be anything from a one-page mathematical proof to a simple thought-experiment to a backyard contraption to a billion-dollar lab experiment to a decades-long development of a theoretical framework. The former view of a scientific method is good enough to be discussed in a nursery class where kids don’t even realize that something could be subtracted from 0 whereas the latter is what actually happens in the real world of scientific research. Though, even the real researchers could be in denial of this fact most of the time, because the early nursery education is quite hard to override, even by the time one becomes a faculty member. A personal example of this: after I finished my talk on “3d supersymmetric localization” at SNBose and asked one of the senior professors what he thought about the talk, he replied, “I am a real physicist”! I laughed out loud, and thought, “Oh, he’s that kind of a physicist!”. By “that kind” I, of course, mean someone who hasn’t been able to move past the above-mentioned nursery education.
Someone at this point will surely interject and say something like, “what about the real world?” or “what about this thing’s usefulness?” or “what about the real world applications?” or “when will I actually need this in my real life?”. For all those interjectors, I point my index finger towards the future posts which I will write on this blog slowly and steadily, but surely, as I continue burning various bridges. Because why not? In short, here are my two cents: Have you seen the real world recently? Why the hell would I ever think about it, except in my nightmares? Supersymmetry and Superspace is a much better and nicer place to live in and it turns out to be quite useful to avoid the real world, and that’s all I need in my real life!
That went off in a different direction than intended so let’s get back on track with another excerpt from the book.
The search for knowledge of practical value can serve as a corrective to uncontrolled speculation, but explaining the world has value in itself, whether or not it leads directly to anything useful.
This again echoes what I said above or rather, what I said above echoes these thoughts of Weinberg. Of course, it’s the latter.
We get intense pleasure when something has been successfully explained, as when Newton explained Kepler’s laws of planetary motion along with much else. The scientific theories and methods that survive are those that provide such pleasure, whether or not they fit any preexisting model of how science ought to be done.
Weinberg so eloquently expresses the need to throw away the “outdated” view of the scientific method, which according to him, had outlived its usefulness already at the time of Newton. And finally,
The rejection of Newton’s theories by the followers of Descartes and Leibniz suggests a moral for the practice of science: it is never safe simply to reject a theory that has as many impressive successes in accounting for observation as Newton’s had. Successful theories may work for reasons not understood by their creators, and they always turn out to be approximations to more successful theories, but they are never simply mistakes.
Well-said but it seems this moral is not taken seriously even by many self-appointed real physicists in this day and age!
That’s quite a long post which I definitely did not intend for it to be. So let’s leave it there, as I move on to another book of Weinberg: