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Prerequisites to truly enjoy the Feynman Lectures?

  1. Jun 8, 2012 #1
    Hello all!

    I'm just out of high school and have got a few months before college begins. I think I'm fairly good in high school math, and now I've just started self-learning Single Variable Calculus (Calc I) from MIT OCW Scholar.

    I love Physics, and aim to be a physicist someday. I recently obtained the Feynman Lectures from my town library, and really enjoyed Prof. Feynman's quirky, yet detailed way of explaining Physics.

    But as I glanced some of the later chapters, I found the math to be quite unfamiliar compared to what I've learnt so far.

    So I was wondering, upto what level of math do I need to be proficient in, to truly understand the Feynman Lectures?

    Thanks in advance!
  2. jcsd
  3. Jun 8, 2012 #2
    Feynman builds up the math as he goes along (or maybe he relies on a math class being tought in parallel). That may not be quite enough to fully understand everything right through the end, but I would not care at the moment. Just keep reading and enjoying.

    Even if you don't grasp the details you will get an overview, and that is extremely useful when you are following a detailed university class.

    If you have specific questions about anything you can always ask here.
  4. Jun 8, 2012 #3
    I would suggest to continue: if you have successfully completed Calc I and understand derivatives/integrals in at least a basic form, then you should be OK. A lot of what is presented is basically a 'change of form' more than any new technique. You may have to do some self-investigation to translate what form he is using to one you understand, but that is a difference you will have to learn to deal with anyhow. You may find that you'll do some checking on a derivation he did and realize you knew what he was doing - he just wrote it in a slightly different way than you are used to or perhaps used a property/shortcut that you weren't aware of.

    Even if you don't do the extra little 'translation' to fully understand the math - the high level concepts still are very important. It drives my wife nuts, but I listen to Feynman lectures in the car on long trips - even if it's just in the background
  5. Jun 8, 2012 #4
    M Quack writes:
    I frankly could not agree less with M Quack's pedagogical advice. Physics is a mathematical description of Nature. If you do not follow the mathematics in FLP (or any other physics textbook), then you are not really learning physics, and can very easily misinterpret what you are reading. Glossing over the mathematics leads to confusion, which I would not characterize as "extremely useful." You should not only read and understand each lecture in its entirety, including the mathematics, if you really want to learn something from it, you should also work on solving related physics problems; That is the only way to insure that you understand what you read in more than a superficial way.

    mege writes:
    I am mystified by what "change of form" in the mathematics of FLP requires "translation" in order to understand it. The mathematics is not in some special notation that Feynman made up, which needs translation, but in standard notation that is in common use. And again, the notion that one can understand FLP (or any physics textbook) without understanding the mathematics in it is false. "High level concepts" derived from such an incomplete reading can reflect only a superficial understanding.

    The students who took this course from Feynman in 1961-63 were, like you, just out of high school when it began. Most of them had not studied any calculus; almost everyone in the class was taking a 1-yr introductory calculus course concurrently. So, you will find some discussion of mathematics in FLP (for example, there are brief discussions of differential and integral calculus in chapter 8, vectors and vector algebra in chapter 11, complex numbers in chapter 22, differential equations in chapters 23-25), but it isn't enough on its own. You will need a practical understanding of basic differential and integral calculus if you want to read (and understand) FLP Volume I from beginning to end.

    Michael A. Gottlieb
    Editor, The Feynman Lectures on Physics
    Last edited: Jun 8, 2012
  6. Jun 8, 2012 #5
    Prerequisites to enjoy??? Its like asking what are the prerequisites to enjoy the Shakespeare or Dostoevsky. If you can read English or Russian, you should be able to enjoy it. This is not to say that translations are not enjoyable.

    As to the understanding, FLP are the type of books that will keep certain secrets away from you during your first, second and even third passages. However, they will teach you more and more (like good books should) as you re-read them. So, who cares what other people tell you??? Dive right in!

    I will leave you with a quote by RPF himself: “Study hard what interests you the most in the most undisciplined, irreverent and original manner possible.” I really wish I could put this quotation as an answer to all the posts on here that ask in an insecure manner whether one is "fit" to do physics or math or whatever else. Who cares??? If you enjoy it enough, do it!
  7. Jun 8, 2012 #6
    I agree with you completely. To appreciate Shakespeare (in the original) you need to be able to read and understand (16th century) English. Similarly, to appreciate FLP, you need to be able to read and understand the mathematics in it.
    Of course if all you are doing is having fun it does not really matter whether or not you have a deep or superficial understanding of what you read - if you are confused, who CARES? - you probably won't even be aware of it. But, you see, I was assuming that the original poster, who is preparing for college and plans to become a physicist, actually wanted to learn physics, and not become confused. (Learning physics is not all fun. It is often very hard work.)
    I will leave you with (a more directly relevant) quote from Section 1-3, Mathematics for Physics, in Feynman's Tips on Physics: A problem-solving supplement to The Feynman Lectures on Physics by Feynman, Gottlieb, and Leighton. It comes from a review lecture Feynman gave to his undergraduate students in 1961, shortly before their first mid-term exam in the course whose lectures were later used to create FLP:

    1-3 Mathematics for physics

    So, this guy comes into my office and asks me to try to make everything straight that I taught him, and this is the best I can do. The problem is to try to explain the stuff that was being taught. So I start, now, with the review.

    I would tell this guy, “The first thing you must learn is the mathematics. And that involves, first, calculus. And in calculus, differentiation.”

    Now, mathematics is a beautiful subject, and has its ins and outs, too, but we’re trying to figure out what the minimum amount we have to learn for physics purposes are. So the attitude that’s taken here is a “disrespectful” one towards the mathematics, for sheer efficiency only; I’m not trying to undo mathematics.

    What we have to do is to learn to differentiate like we know how much is 3 and 5, or how much is 5 times 7, because that kind of work is involved so often that it’s good not to be confounded by it. When you write something down, you should be able to immediately differentiate it without even thinking about it, and without making any mistakes. You’ll find you need to do this operation all the time—not only in physics, but in all the sciences. Therefore differentiation is like the arithmetic you had to learn before you could learn algebra.

    Incidentally, the same goes for algebra: there’s a lot of algebra. We are assuming that you can do algebra in your sleep, upside down, without making a mistake. We know it isn’t true, so you should also practice algebra: write yourself a lot of expressions, practice them, and don’t make any errors.

    Errors in algebra, differentiation, and integration are only nonsense; they’re things that just annoy the physics, and annoy your mind while you’re trying to analyze something. You should be able to do calculations as quickly as possible, and with a minimum of errors. That requires nothing but rote practice—that’s the only way to do it. It’s like making yourself a multiplication table, like you did in elementary school: they’d put a bunch of numbers on the board, and you’d go: “This times that, this times that,” and so on—Bing! Bing! Bing!

    Michael A. Gottlieb
    Editor, The Feynman Lectures on Physics
  8. Jun 8, 2012 #7


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    My $0.02:

    If you read through Feynman now, there will be parts you don't understand, but there will be parts that blow your mind.

    If you read Feynman two or three years from now when you're in the thick of your undergrad years, you will understand most of the math, and there will still be parts that blow your mind.

    If you wait until after your grad school classes, you will understand all the math, and yet still there will still be parts that blow your mind.

    My advice: do all three. Read it now, again in a few years, and again a few years after that. Each time you will get something new out of it.
  9. Jun 8, 2012 #8


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    That's the best advice in this thread
  10. Jun 8, 2012 #9
    Thank you all for the replies! :)

    Ah, I believe I made a typo in the title there. Of course, I only meant my worries over really understanding the mathematical technicalities behind the physics. Who could possibly not enjoy Feynman? I read "Surely You're Joking, Mr. Feynman" completely in one sitting! :D

    From what you guys have told me, I've decided to simply continue reading and re-reading the Feynman Lectures without worrying much over the math. While at the same time, a clever guy once advised me, that in Physics, the math can never be ignored, it can at best be postponed. So, I'm going to improve my math skills simultaneously too, as I'm definitely going to need that, if I'm to be a physicist.

    Thank you all for helping me out! A special thanks to YAHA and lisab; your replies kinda opened my eyes. :D
  11. Jun 8, 2012 #10
    I would like to point out that FLP has three authors, Feynman, Leighton and Sands, all of whom made significant and original contributions to the book. The book would not exist at all without Leighton and Sands, who conceived and directed the program that created it - they did all the actual writing and illustration: Feynman didn't actually write a single word of FLP, though of course its chapters are based on tape recordings and photos of the lectures he gave.
    If you gloss over the mathematics in FLP, you won't get very far beyond the introductory (easy, non-mathematical) lectures before you find yourself hopelessly lost and confused, because one thing builds on another in FLP, and it all depends on mathematics. I strongly suspect the people who advise you to read FLP while ignoring the mathematics have never read the book from cover to cover themselves with comprehension.

    Please take a look these notes from Feynman's original course, which include the students' homework assignments, tests and quizzes. As you read FLP, you should be able to solve these problems too. The students in that course were no more mathematically sophisticated than you are now when they started it.
  12. Jun 8, 2012 #11
    You are welcome and enjoy! However, I want to make clear that math is crucial! Limited by the current understanding, it is the language that nature speaks in! I hope that as you read the lectures and encounter certain things like, say, tensors, it piques your curiosity and you investigate that area of math on your own or at least put it on your "to study" list. It is in this that I agree with codelieb. However, in the rest, he takes and overly didactic attitude and makes it seem like one shouldnt come around FLP until he obtained an MS in mathematics. Although I admit that such attitude (it maybe wrongly perceived on my part) subsided in the last post ;)
    Once again, enjoy
  13. Jun 9, 2012 #12
    I am NOT saying that one needs a an MS in mathematics or even a BS in mathematics to read FLP. FLP is a textbook based on a course taught to freshmen and sophomores at Caltech; It is appropriate reading for someone who has just graduated high school with little or no knowledge of calculus, if calculus is learned concurrently (as it was by Feynman's students). All I am saying is that the mathematics should be understood by someone who is reading FLP, and not glossed over. Half the book, or more, is mathematics. If you don't read the math (and understand it), then you are not reading FLP (or understanding it).
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