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Roger Penrose's book

  1. Jul 6, 2006 #1
    Not sure where to have posted this..
    but has anyone read..."The road to reality: a complete guide to the laws of physics" by Roger Penrose. (massive book)
    what are your views on it?
    not sure whether I should carry on reading it, leave it for another day? (very big book) havn't even finished 1st chapter, but i did just buy it today.
    I got other books to that look really interesting that I'm eager to get on to reading.
  2. jcsd
  3. Jul 6, 2006 #2


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    It depends on your background. I have read reviews by people who had loved Brian Greene's books but *hated* Penrose's book.

    I, on the other hand adore Penrose's book!! It is so full of insights and fresh presentations of a huge range of subjects. It is wonderful to see his views on all those topics. I consider it a gold mine. *But*, I have a PhD and postdoc experience in theoretical particle physics and that is part of the reason that I enjoy so much his book. This is not a book, imho, good to learn things from scratch because one needs to do calculations to get used to a new formalism. But it's a wonderful book to give a deeper understanding if one has already some basic knowledge of the topics covered.

    My two cents

  4. Jul 6, 2006 #3
    I really like the book, written by a great mathematician!

    I would have prefered not to see Penrose's platonic views on math with relation to reality in this book. I have no problems with his views on that but he could have written that in another book "Penrose's metaphisics" or so. :wink:

    Hopefuly in a next edition the publisher will hire a professional illustrations team, here is a great opportunity to make the book even better.
  5. Jul 7, 2006 #4
    It's definitely not aimed at the general public I think. Though it starts simply, it gets horribly complicated very quickly. It took 3.5 years of a maths degree before I hit stuff like differential geometry or black holes and he covers it in what might take a quick reader only a few days.

    Definitely something to get a maths or physics undergrad interested in more than just their own area of interest but to the uninitiated, it's like a HUGE textbook of ideas but goes through them so quickly it's not even close to 'easy reading' like 'The DaVinci Code' is (ie, that's an incredibly simple book).
  6. Jul 7, 2006 #5
    I find the book to be very helpful as a tour guide of physics. Since I am still new to physics, I read a chapter (or even less), then look for textbooks or online sources that reinforce this knowledge with calculations and problems. This makes for very slow progress (I've been working for a month or so, and I'm only on chapter 5!) but I have a more solid understanding of the topics.

    If you want to learn what the book is telling you, then I highly recommend doing the exercises. It really helps you to understand what you're reading, even if you never get the right answer (I sure don't).
  7. Jul 8, 2006 #6
    "(I've been working for a month or so, and I'm only on chapter 5!)" - Saketh........wow, well ive managed to finish first chapter, thought it was really good, especially the way he described mandelbrot?. set like it exist out of space and is timeless, and linking mathematical word to the physical and 'mental' word, but started second chapter maths has started to creep up, he did say 1st 16 chaps are on maths o well, Im not afraid of maths. I'll give it ago. I've done A Level maths and physics...maybe I'll be ok? I always wanted to find a book like this one that tells the physics aswell as showing the maths behind so i can understand it, hard to find these kinds of books as most popular ones are without maths.
    Last edited: Jul 8, 2006
  8. Jul 8, 2006 #7


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    The maths sometimes is beyond A-level so you may struggle there but his explainations are lengthy and very good. Thats not to say that you may have to read them twice.
  9. Jul 10, 2006 #8
    ok...i was working on one of his excersises (sp? ugh) he asked to prove...
    Area of a spherical triangle is = R^2( alpha + beta + gamma - pi)...he gave a picture of a sphere with the triangle on it to help.
    (can't get the hang of latex) where alpha, beta, gamma are angles of the spherical triangle...
    i managed to get to..
    Area = R^2( pi/a + pi/b + pi/c -pi) i introduced the 1/a and 1/b, 1/c initially as the fraction of the total area of the surface area of the sphere, i can justify replacing 1/a with alpha, etc...because each fractional area will have a corresponding angle (of the triangle/angle of segment of sphere) which its directly proportional to. but im confused as to where the pi comes into, i know pi rad =180 deg. so thats like saying fraction of total angle of euclidean triangle...anything ? sorry if i confused you.
  10. Jul 12, 2006 #9
    never mind I think i got it., i was wondering does the pi in 4pi.r^2 got anything to do with pi radians? of just a constant.
  11. Aug 3, 2006 #10
    I'm upset that the answers to the problems in the book are actually not online (like the book says they are, and how reviewers said they were, and how the Amazon.com product description said they were)! I was so excited to work on challenging problems and test my abilities in a vigorous approach. Alas, over a year and still no problem solutions. This book lost more than half its value when I realized that the solutions were just not coming. Those little smilie faces at the bottom of so many pages appear to taunt me. :frown:

    Anyway, even though this is my first exposure to some of these areas of mathematics, it's pretty obvious that he skipped many, many important things critical to understanding Riemann surfaces, groups, and complex manifolds. I understand the need for brevity, of course. But without the answers to those problems, I am left at a loss for what it is I should actually be learning from this book.

    I tend not to continue reading part of a book or piece of literature, if, after a while, I do not have the sense that I am understanding something. Instead, I will stop and read a page or a chapter over and over again until I understand it. That is the wrong way to read this book. Just keep reading. If you don't understand anything, that's actually a good sign. It's a sign that you should keep walking down this "road to reality," and what you should be doing along the way is looking for other signs that will help you along. :smile:
    Last edited: Aug 3, 2006
  12. Aug 3, 2006 #11
    I just started reading this also. I'm definitely no physicist, but I'm interested in the subject. I love a challenge, which i know this book is to me, but I do have one complaint. The book doesn't flow logically for beginners. I can follow him perfectly to a point, then he'll throw in an idea or equation that is completely foreign and say , 'This will be explained throughly in chapter XX'. In the meantime (the next 10 or 15 chapters) I have no idea what the hell was going on. It's almost like you should breeze through the book once, get an idea of what's going to happen, and then start over and buckle down.
    Regardless, I think Penrose writes well and I've never seen such a comprehensive book. I really want to dig in and LEARN things that most people in the field only memorize and regurgitate.
    If anyone is interested in corresponding it might make it easier to plug through this book. I'm only on CH 3 and would love to discuss following chapters with others. Maybe we could help each other when we get stuck. It's tough to go through these books when you're not in a classroom environment.
  13. Sep 7, 2006 #12
    I brought the book about a few months ago, though I have stopped reading it since then to try and read something else which I hope should help me understand this book a bit better.
    I've only read the first chapter so far, and found it very challenging but im slowly getting there. I found the part about axioms and platonic views really intereseting. I have wondered the same, does all mathematics have a relation to the physical world?

    Sounds like a good idea to me! I'll deffinetly need some help at some point while reading this book.
  14. Sep 7, 2006 #13


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    How does it differ from The Emporer's New Mind.

    I'm rereading ENM - it's a nice walk through the world of classical to modern physics, with specifics to computation.

    Does the Road to Reality specilise in something different?
  15. Sep 7, 2006 #14
    I haven't read ENM, but RTR is sort of a thorough guide to all of physics... or at least that's what it seems like.

    I like it, and have read some bits, but I really haven't understood much. I have 4 bookmarks in various parts where I have dipped in, but I can barely get through it as it is so tough. Maybe one day I'll read the whole thing through, and understand it, and learn a lot from it, but until then, it's just going to sit on my shelf. University is enough of a challenge as it is.
  16. Sep 7, 2006 #15
    yea good idea denni, id like to know the answers to those questions too, ive tried a few...mostly 'prove this' types so i can see if im there or not.
  17. Sep 8, 2006 #16


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    Is there an underlying theme, like computability in ENM?

    (ENM also contains a nice history of physics from Newton/Galileo to Einstein/Poincare/Minkowski through to Quantum theory.)
  18. Sep 16, 2006 #17
    I think the book is awesome. I give Penrose the credit for my taking a chance at majoring in Physics. After reading his book, I just had to know the equations behind all the wonderful theories I've read in other books like Brian Greene's. I also gained an appreciation for math and how neat it can be. I have a fascination with the tensor notation now. lol It's definitely a tough book to understand, and I'd say you won't understand most of it if you don't have a background in math or physics. After Calculus, I was mostly gone, but I still pushed through. The Physics sections are a little easier to understand and follow, and I think he does a good job at explaning theories and their developemnt and possible flaws. I was actually losing some of my excitement about how wonderful string theory sounds and was reinvigorated by his writing on it, despite his opposition to it.

    I am also saddened by the fact that Penrose never did put up the answers to his problems even if I would have only understood a few of the earlier chapters. :( I plan to read this book a few more times and hope I learn more math in between each reading.
  19. Sep 16, 2006 #18
    An online reading discussion might be a bit like herding cats, but I'd like to see them for various books. I've always had an ambition to read through ALL of MTW for example.

    Put me down as interested. I don't even have the book yet, but it's cheap enough used.

    The paperback is coming out in January. Wonder if that'll have corrections.
    Last edited: Sep 16, 2006
  20. Nov 19, 2006 #19
    Dr. Penrose has wonderful insights, but you have to understand the material at some level before you can understand his book.

    You are not going to learn the math and physics from the "Road to Reality" unless you are some kind of genius. If you have completed complex analysis and tensors, you probably can struggle through it. Topology and Diff geometry would help too. In that sense it is a lot like Feynman's books. Learn your physics and math first and then go back and read them.
  21. Dec 1, 2006 #20


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    The homepage http://www.roadsolutions.ox.ac.uk/
    says "Please note that the corrections page has been updated 26/09/06" and points to
    http://www.roadsolutions.ox.ac.uk/corrections.html [Broken]
    which says "NEW CORRECTIONS (incorporated into new paperback editions from 2007)"

    I will have to print out this page and staple it to my hard cover edition.:grumpy:
    Last edited by a moderator: May 2, 2017
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