Feynman Lectures on Physics (1964) | Hacker News Reader

Feynman Lectures on Physics (1964)

feynmanlectures.caltech.edu

222 pointssethbannon67 comments

> Feynman Lectures on Physics now online

It's been online since 2013. [1][2]

[1]: https://www.openculture.com/2013/09/the-famous-feynman-lectu...

[2]: https://en.wikipedia.org/w/index.php?title=The_Feynman_Lectu...

Coincidentally 2013 is also the copyright date of that announcement site. So if we assume that "now online" was refering to the time the page was published in 2013, they are spot on.

For the rest of is this serves as a reminder that we should also think about how our texts read a decade in the future.

Its Volume III (quantum mechanics) that really changed physics education, imho.

It dispensed with a long tradition of continuous PDE's (Schrödinger equation) based approaches (which needlessly obscured the essence of quantum behavior) and brought to the fore discrete systems (like spin) and the beautiful Dirac notation (so he, too, stood on giant's shoulders).

Feynman really is the grand-master of KISS and the nemesis of obfuscation.

We should all be a little bit like Feynman.

If you folks have any questions about the Feynman Lectures Website, the online edition of The Feynman Lectures on Physics, the current ("New Millennium") printed edition (or ePub or Mobi editions), then you can ask me. I am the person who is primarily responsible for them. The same goes for the previous ("Definitive") edition. I've been working with The Feynman Lectures on Physics for about 23 years.

Very cool! I'm a huge Feynman fan, and he has a dedicated corner in my library. If I'm not mistaken, I probably own a book you coauthored with him. Thank you for the all the effort you've put into making the Feynman Lectures accessible to anyone with an internet connection.

This is not a question about the website, but I think there might be a chance you know something about it. In Feynman's "Cargo Cult Science" speech [1], there's this anecdote about ways we might fool ourselves in science, using measurements of the elementary charge as an example:

> We have learned a lot from experience about how to handle some of the ways we fool ourselves. One example: Millikan measured the charge on an electron by an experiment with falling oil drops and got an answer which we now know not to be quite right. It’s a little bit off, because he had the incorrect value for the viscosity of air. It’s interesting to look at the history of measurements of the charge of the electron, after Millikan. If you plot them as a function of time, you find that one is a little bigger than Millikan’s, and the next one’s a little bit bigger than that, and the next one’s a little bit bigger than that, until finally they settle down to a number which is higher.

> Why didn’t they discover that the new number was higher right away? It’s a thing that scientists are ashamed of—this history—because it’s apparent that people did things like this: When they got a number that was too high above Millikan’s, they thought something must be wrong—and they would look for and find a reason why something might be wrong. When they got a number closer to Millikan’s value they didn’t look so hard. And so they eliminated the numbers that were too far off, and did other things like that. We’ve learned those tricks nowadays, and now we don’t have that kind of a disease.

Do you happen to know anything about this plot of measurements of elementary charge? There have been some efforts to reproduce it [2], but IMO they don't really match Feynman's description.

[1]: https://calteches.library.caltech.edu/51/2/CargoCult.htm

[2]: e.g. https://scipython.com/blog/measurements-of-the-electron-char...

Thanks for buying my book. You're very welcome for the website. I don't know specifically to what plot Feynman was referring, but it may have been one he made himself.

Is it worth putting a link to the “lectures on computation” and “lectures on gravitation” books on the site? Unless I’ve missed it they don’t seem to get a mention.

Given that these are ~60 years old by now, can someone that knows both the fields they cover and has gone through them explain what, if anything, they are missing ?

Maybe some mention of quantum information science / cosmology / biophysics. But it is probably ok to not include these things in an intro sequence. I am saying this as someone that used these lectures to prepare for the physics Olympiad, then went on to a PhD in Physics, and is now a professor.

I think tomes 1 and 2 are still awesome ways to study the given topics. I do not feel as strongly about tome 3, but I still do like it.

This kind of demonstrates that at the fundamental level, physics has been stagnating for quite a while, no?

Imagine, during the time the Feynman Lectures were created, trying to study using 60-year-old material. Utterly unthinkable. You wouldn't even know about neutrons. In fact, you would barely be able to understand what an atom is. You would be completely ignorant of quantum mechanics. Relativity would be cutting edge, with many important models not yet known.

But today, despite immense research effort over decades, using some of the most expensive equipment ever built, there isn't much fundamentally new to add to the Lectures, except a few more particles and a couple new quantum phenomena.

You could say the same for many fields, even computer science: a textbook from the 1960s would cover data structures, compilers, filesystems, common algorithms and numerical methods, boolean algebra, etc. - not too different from what one would learn today.

Scientists generally explore the biggest, most fundamental questions first, which ends up being foundational knowledge for students generations later. Most of the modern advances in physics have been past the undergraduate level.

Physics is centuries old though. Computer science is not. That physics changed so dramatically in the first half of the 20th century is certainly surprising, considering that the field already had a long history behind it.

Precisely because physics is centuries old, you'd expect that the things we teach beginners are settled. We teach them even though we know they're wrong, but there is pedagogical value in teaching it this way. I doubt we'll be teaching quantum gravity to freshmen in 100 years (assuming we'll have it solved by then), they'll still learn classical mechanics first.

Newtonian mechanics is still sufficient for almost all the engineering needs we have today.

What about electrical/EM, electronics, semiconductor and chemical engineering, SR and QM enter those fields?

The EM and thermodynamics from 1899 is enough for most of these fields' day-to-day work. Even transistors which are inherently-quantum-mechanical need zero quantum mechanics for their application. You do need quantum mechanics to discover the transistors though.

However, there were pedagogical discoveries since then. We have better mathematical notation / conventions / naming for some of these topics that makes them easier to teach today.

The lectures predate the standard model, so your assessment is incorrect. Fundamental physics has advised in the mean time.

But should you expect advances in physics to affect an introductory physics resource? It's not like people learning general physics are exposed to quantum field theory in any case.

There is a lot of material the lectures do not go anywhere near, they're for first years in modern terms at least.

> This kind of demonstrates that at the fundamental level, physics has been stagnating for quite a while, no?

Yes just like computers. Since 70 years they still fetch instructions and execute them, no improvement in this field. /s

That's good, isn't it? It means we've discovered the actual fundamentals of several areas. People still need to know how forces work, thermodynamics, that kind of thing.

New areas build on those areas so we don't expect them in a course about the fundamentals.

It would be concerning if every 20 years the lessons got completely turned upside down.

Exactly. No one complains about the lack of breakthroughs in geography.

Well, people complain about the unmapped areas of the ocean floor (the vast majority of it) all the time. [1]

[1]: https://www.earthdate.org/episodes/our-unmapped-ocean

> It means we've discovered the actual fundamentals of several areas.

But there is some evidence that this is not the case. For example, quantum field theory and general relativity are not quite compatible. [1][2] The mechanism for charge formation in triboelectric effect (when you rub things together) isn't well-understood. [3][4] Turbulence still cannot be analyzed satisfactorily. [5] This last one is even mentioned in the Feynman Lectures [6].

Also, generally, I think we should be very skeptical of the claim that we live at the pinnacle of human achievement and the end of the history. It seems quite arrogant to me, and it's against the spirit of the Copernican principle.

[1] https://www.npl.washington.edu/av/altvw204.html (Renormalization: Dodging Infinities)

[2]: https://arxiv.org/abs/1009.2157 (The Problem of Time in Quantum Gravity)

[3]: https://en.wikipedia.org/w/index.php?title=Triboelectric_eff...

[4]: https://link.springer.com/article/10.1007/s40820-020-0373-y

[5] https://arstechnica.com/science/2018/10/turbulence-the-oldes...

[6]: "Finally, there is a physical problem that is common to many fields, that is very old, and that has not been solved. It is not the problem of finding new fundamental particles, but something left over from a long time ago—over a hundred years. Nobody in physics has really been able to analyze it mathematically satisfactorily in spite of its importance to the sister sciences. It is the analysis of circulating or turbulent fluids." (https://www.feynmanlectures.caltech.edu/I_03.html)

> Also, generally, I think we should be very skeptical of the claim that we live at the pinnacle of human achievement and the end of the history. It seems quite arrogant to me, and it's against the spirit of the Copernican principle.

Did someone claim this?

> Did someone claim this?

Not you, but I think it's a common sentiment.

The rate of discovery in physics is pretty slow over the years - since it's a pretty old science (I'm being very broad)

I think we have a skewed view of physics research because many discoveries were simply done by sharing between fields and generally global instantaneous communication/universal access to information - before we had the phone or the internet, good luck learning about as many things as you could in the 60's - or today!

The last century was kind of science on steroids, since for the first time in history everyone could connect many others ideas - everyone suddenly was standing on the shoulders of all the giants the wanted. But at some point, we'll have went through everything there is to see up there, and we'll need to go down, and look for new heights.

It's entirely possible that we've ran through the " low hanging fruit" of physics discoveries, as there are virtually no barriers between individuals and information since a good two decade I'd say, and sharing globally for about 100 years.

Maybe sharing and learning from one another is not fertile anymore, and we need to support smaller quirkier experiments and fundamental research to discover more tidbits to connect and make new discoveries.

Has math not changed because freshman calculus hasn't changed in the same amount of time?

Judging a field by what's taught to freshman is a poor metric for progress on the frontier.

"I do not feel as strongly about tome 3, but I still do like it."

Is that because QM has moved on or is it now viewed from a somewhat different perspective and thus taught in slightly different ways?

I personally just did not use it as much, so I am not comfortable offering a review.

Thanks, that's as good a reason as any.

Actually, the treatment of QM there is still quite modern, if more “physical” compared, say, to Susskind’s recent book.

> Maybe some mention of quantum information science ...

Not quite "quantum information science" per se, but Feynman's "Lectures on Computation" (1996) provides fascinating insights into information theory as well as quantum physics in micro-chips. Again, as it is always the case with Richard Feynman, you will find lots of interesting non-trivial ideas in his books whether you are novice or expert.

I’d assume quantum gravity stuff?

The Feynman lectures are introductory courses, not comprehensive studies of all of physics. They don't even cover gravity (meaning General Relativity). Quantum Gravity is very advanced stuff, you wouldn't expect it in these books.

The quantum mechanics stuff misses EPR & Bell's theorem, which roughly says that the probabilities in quantum mechanics are essential. Experimental confirmation of this won the Noble Prize last year. Feynman famously counseled one of the winners not to work on it, as Feynman thought it wasn't interesting.

It also misses quantum seeing in the dark and the Elitzur–Vaidman bomb tester. In the two slit experiment, if you detect a particle where there's supposed to be a node, this means one of the slits is blocked. So, you can detect that one of the slits is blocked from a particle that went through the other slit.

A good modern textbook is Mastering Quantum Mechanics by Barton Zwiebach of MIT. His courses on MITx and open courseware are really great.

Edit: Also, all of computational physics.

There is something different about the way the Feyman lectures is written.

It's been years since I have read it, but I remember it explaining how one could derive the change in atmospheric pressure with altitude by just knowing a few properties of the gas.

I don't remember the derivation, and I am not sure I could reproduce it. But it changed how I thought about a lot of physical phenomena.

I really like the extra audio bits before and after the lectures proper - they were removed on the commercial CDs. (“Why don’t they turn up on time!”)

What sets physics apart from the other physical sciences that there are no "X Lectures on Chemistry" or "Y Lectures on Biology"? Surely if there was a will, there would be a way. Genuine question. Feynman's work may not be the be-all, end-all of physics, but it covers every base. Would it be possible to do that for other fields?

When I was in a condensed matter PhD program at Cornell they ran an excellent weekly Colloquium series which I always looked forward to even if the topic was astrophysics or particle physics.

I went looking and didn't find anything in Math, Chemistry or Computer Science that came close to the quality of the talks and the feeling that the large department was a community of interest.

I'm not sure if I understand what you're trying to convey with the following: "X Lectures on Chemistry" or "Y Lectures on Biology"? Chemistry and Biology are higher level abstractions of physics, Sure you can communicate the physical properties that are happening, but the abstractions we create help us to communicate the relevant physical properties we are trying to understand/ manipulate.

Also, I love Feynman's work, It's what made me see the beauty in physics, but to say that it covers every base is completely wrong and an injustice to his findings and the broad nature of the field.. Are you trying to say that he was great at communicating abstract concepts?

I think it's because what constitutes core physics is more standardised and less variables across universities. In addition, the core syllabus of physics tends to have concepts that build on the previous very nicely and ultimately combine. In constrast, I think other subjects tend to specialise more quickly than physics.

Fundamental physics has an extremely neat set of concepts and ideas at its core,, forming a kind of funnel, whereas chemistry and biology would be more like a plate.

Also the Feynman lectures are really a tour of basic undergraduate physics rather than literally all of physics so potentially it could be that no one bothered to make one. Physicists seem to enjoy the Shakespearean side of pedagogy a bit more than chemists.

I would recommend Eric Lander's introduction to biology course at MITx as the perfect counter-example. It is about as good as Feynman's lectures, whether one chooses to refer to it as "Lander's lectures".

It's worth pointing out that experts love Feynman's lectures. They're elegant and subtle, and are great for refreshing why and how you think about physics.

Pedagogically, Feynman's lectures were a failure. They aren't well structured to teach novices physics. Outstanding students might learn from them, but those same students would also learn from a ratty textbook.

I'm a physicist with a PhD, so I love Feynman's lectures. I also care about pedagogy and my students' development, so my copy of the lectures sits next to my copy of Jackson and Sakurai, on a high shelf that first-years can't reach!

For biology at least, my professors often said that by the time a textbook was published, it was 5 years out of date.

The writing style is practical, straight-forward to me. Such an inspiration to the world of Science.

I bought the printed versions about 15 years ago, not to prepare for anything but to "leisurely" read about Physics.

Richard Feynman had the uncanny ability to explain something at a level where it makes sense, and then back it all up for math.

I was saddened at the poor audio quality of the audio lectures. Surely someone could thrown AI at it to improve the quality.

Only the first one is pretty bad, the others are quite good in my opinion.

We are currently working on a 'reconstruction' of the first lecture recording, which we hope to publish at The Feynman Lectures Website later this year.

Oh nice, thank you for letting us know.

The FLP lecture recordings posted at The Feynman Lectures website are "archival" recordings derived from the original 1/4" reel-to-reel tapes, which were digitized at high-resolution in 2010. They are "archival" in the sense that no editing or audio-engineering was applied to them before they were reduced to podcast quality for publication online. We used the best OGG and AAC codecs available, and all but the first lecture, which was recorded poorly in 1961, are "good enough" in the sense that you can understand everything Feynman is saying - in fact I think they sound pretty good. Basic Books, the publisher of FLP, is currently working on a commercial edition of the lecture recordings, which will be edited and audio-engineered, so they should make audiophiles happier, but for the purpose for which they are intended, learning physics, I think the online versions (other than the first lecture) are more than adequate.

I remember having volume 1 on 6 cassette tapes for listening in the car. Peak entertainment in those days kids.

Can we get a 2013 added to the title?

The Feynman Lectures on Physics (1964) - https://news.ycombinator.com/item?id=30792902 - March 2022 (62 comments)

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Why do they repeat in the audio the lecture title and date three times?

I assumed that was to help get a reasonably long sound level check for the recording.

The title is misleading. That website has existed for a long, long time. I remember reading lectures there at least five years ago.

Unfortunately, I cannot prove it, because the domain has been excluded from the Internet Archive for some reason. But I can tell you with complete confidence that the lectures have not just "now" gone online.

Same. I do remember seeing them on cal tech website for free. Honestly amazed that such great content is out there for free.

We've changed the title now. (Submitted title was "Feynman Lectures on Physics now entirely online")

Supporting evidence: https://news.ycombinator.com/item?id=36018344

I think the audio recordings were added more recently than the text. I used to have to listen to my commercial CDs of the lectures while reading the online text.

The lecture recordings were added to The Feynman Lectures Website in 2021. It was not easy to convince the publisher (Basic Books) who licenses the exclusive publication rights for The Feynman Lectures on Physics (including the recordings) to allow us to publish them online for free listening. In fact it took many years of persistent pestering. :-)

The original Feynman Lectures Website was feynmanlectures.info, which went online in 2006. The online edition of The Feynman Lectures on Physics was published there in 2013, and also mirrored at a new Caltech website, feynmanlectures.caltech.edu. Some years later (I forget exactly when) feynmanlectures.info was shut down and its contents was moved to feynmanlectures.caltech.edu/info.

Is this new? I can't find previous version of this page on Internet archive and the page footer did not get updated since 2013 (at least it suggests that the content updated last time in 2013)

Edit: It seems that I'm wrong. There is mention that they updated Original Course Handouts in 2022

> 6. Updated in March 2022 with a new presentation featuring deep-zoomable images.

The "2013" is the copyright date of the initial publication of the online edition of The Feynman Lectures on Physics, but that edition (as well as the printed edition) and the Feynman Lectures Website where it is published is far from static. I have been working on it continuously since 2006 (with occasional help from volunteers), during which time a lot of improvements have been made and much new material has been added (to the website - we are not adding new material to the printed edition, though we have made, and continue to make, corrections, as needed).

"However, we want to be clear that this edition is only free to read, look at and listen to online, and this posting does not transfer any right to download all or any portion of the book The Feynman Lectures on Physics, its photos or tape recordings, for any purpose."

At the time my colleagues and I proposed creating an online edition of FLP, one could only read it in expensive printed editions or in (lousy-looking) pirated PDFs. It was not easy to convince FLP's publisher, which makes a lot of money from FLP sales, that a freely accessible online edition was a good idea! However, we persuaded them, arguing that increased exposure would lead to more, not fewer, book sales. They were still hesitant, but they allowed it, stipulating some conditions, one of which was that downloading/copying the content of the online edition for offline use or distribution would be forbidden. The text you are quoting, written by Caltech's Office of the General Counsel, appears in a footnote on the homepage of The Feynman Lectures Website for this reason.

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