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4.22 AVERAGE
4.22 AVERAGE
challenging
informative
inspiring
medium-paced
This is a good book, I guess... I just couldn’t care less about the subject matter.
challenging
informative
slow-paced
Can't really say I understood all this book serves up, but I do think I understood more than I didn't, and it would be a real feat making this stuff any easier to understand than how it's done here. I'm quite sure my brain has been rearranged in some small way. Granularity's where it's at, man! Kudos to the translator as well!
Rovelli can be quite poetic and beautiful, but for the most part, the writing here is clear and direct and all the more mind-expanding for it. At the heart of Quantum Theory are some big mysteries and it will be fun to come back to this in 20 or 50 years or however long it takes to compare what we think we understood to what we now understand.
informative
lighthearted
reflective
medium-paced
First two thirds were great, very illuminating and lighthearted. He lost the pacing a bit in the last part, became more reflective and philosophical, presumably because he’s talking about even-more-theoretical theoretical physics, which was a bit of a let down for me.
This nonprofessional, who would rate his understanding of modern physics in the top 10 percent of laypeople, found this book relatively easy to understand.
If you're in my general area, you can skip the first one-quarter of the book and start with the start of modern physics and go from there.
Some specific notes.
First, this is obviously NOT about string theory. If that's a reason for you to complain about the book, erm ... I suggest you lessen your enamoration with string theory.
Second, he notes that recent findings, and recent NON-findings, at CERN, notably the finding of the Higgs boson but the NON-finding of other particles for which string theorists have been hoping, is a matter of concern for various versions of that theory.
As for the other physics?
His discussion of the quantization of spacetime was understood by this nonprofessional, as was the basic gist of the idea that LGQ meant we could ultimately move past the idea of time, AND kill the renormalization equations of Feynman in QED. I don't understand QED, but I do understand what it is, which is enough.
That said, while people at my layperson's level of understanding have heard of string theory, and of LGQ, Rovelli doesn't note in detail that other theories attempting to quantize gravity also exist, though he does hint at that when he describes LGQ and strings as the two most common theories. See Wikipedia: https://en.wikipedia.org/wiki/Quantum_gravity
This, and his somewhat impressionistic presentation of the material, almost get the book pulled back to a fourth star at this point. But, I keep it at 5 for its relatively simple explanatory level overall, even if a bit impressionistic, and even more for laying out the gist of a credible alternative to string theory. (Whether or not it turns out to be more credible than the other alternatives at the Wikipedia link is still up for debate.) Also, for his reference to eliminating the need for renormalization, which would seem to be an Occam's razor benefit.
His explanation of why we perceive what we call time, because whenever "we describe (a) system by means of averages of many variables,we have a preferred variable that functions like time," is interesting. Even more, that "time is information we don't have."
I will fault him more for one other issue than his assumption that we can focus just on strings and LQG in theories of quantum gravity.
That is when he talks about the relational theory of quantum mechanics. He doesn't say whether or not, this, or any particular theory of QM, is fundamental to LQG. Nor does he note that there are more than a dozen different theories of QM. Again, see Wiki: https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics
Even worse, perhaps, is that Rovelli doesn't tell us that he's the inventor of this particular interpretation.
And, with all of THAT, yes, it falls to four stars. There's no way of making a better judgment of the likelihood of LQG without knowing if it's that dependent on one theory of QM or not.
(I personally tilt toward the consistent histories theory or something similar.)
If you're in my general area, you can skip the first one-quarter of the book and start with the start of modern physics and go from there.
Some specific notes.
First, this is obviously NOT about string theory. If that's a reason for you to complain about the book, erm ... I suggest you lessen your enamoration with string theory.
Second, he notes that recent findings, and recent NON-findings, at CERN, notably the finding of the Higgs boson but the NON-finding of other particles for which string theorists have been hoping, is a matter of concern for various versions of that theory.
As for the other physics?
His discussion of the quantization of spacetime was understood by this nonprofessional, as was the basic gist of the idea that LGQ meant we could ultimately move past the idea of time, AND kill the renormalization equations of Feynman in QED. I don't understand QED, but I do understand what it is, which is enough.
That said, while people at my layperson's level of understanding have heard of string theory, and of LGQ, Rovelli doesn't note in detail that other theories attempting to quantize gravity also exist, though he does hint at that when he describes LGQ and strings as the two most common theories. See Wikipedia: https://en.wikipedia.org/wiki/Quantum_gravity
This, and his somewhat impressionistic presentation of the material, almost get the book pulled back to a fourth star at this point. But, I keep it at 5 for its relatively simple explanatory level overall, even if a bit impressionistic, and even more for laying out the gist of a credible alternative to string theory. (Whether or not it turns out to be more credible than the other alternatives at the Wikipedia link is still up for debate.) Also, for his reference to eliminating the need for renormalization, which would seem to be an Occam's razor benefit.
His explanation of why we perceive what we call time, because whenever "we describe (a) system by means of averages of many variables,we have a preferred variable that functions like time," is interesting. Even more, that "time is information we don't have."
I will fault him more for one other issue than his assumption that we can focus just on strings and LQG in theories of quantum gravity.
That is when he talks about the relational theory of quantum mechanics. He doesn't say whether or not, this, or any particular theory of QM, is fundamental to LQG. Nor does he note that there are more than a dozen different theories of QM. Again, see Wiki: https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics
Even worse, perhaps, is that Rovelli doesn't tell us that he's the inventor of this particular interpretation.
And, with all of THAT, yes, it falls to four stars. There's no way of making a better judgment of the likelihood of LQG without knowing if it's that dependent on one theory of QM or not.
(I personally tilt toward the consistent histories theory or something similar.)
felt circular in the need for experiments vs data section, but loop quantum gravity sounds cool. will need to reread at some point to fully grasp all of it.
From what I can tell as someone in the humanities, this book does a very good job explaining quantum mechanics, Einstein's theory of general relativity, and the idea of quantum gravity. The books is concise and clear in many instances, which I appreciated. Many of the chapters would be useful if assigned along with fiction in a science fiction course. Two things, however, might be improved. First, the discussion of the shape of the universe and the 3-sphere was inadequate and very hard to follow. Maybe I don't know enough about topology? Anyone have a recommendation for a good explanation of this? Either way, Rovelli or his translator could have worked on this section. Second, the book contains a few chapters that involve a lot of pontificating about religion--both in terms of the ways that the historical development of Christianity downplayed important (and accurate!) developments in physics and the way that Christianity has given us the wrong impression of the universe. While I would appreciate a book that considers that question, it doesn't seem to be the purpose of _Reality is Not What it Seems_ and feels too polemical for the kind of work that Rovelli is doing in other chapters. Overall, though, this is a good source for the layperson who want to learn more about physics.
I love the way this author makes such complicated subjects so easy to understand. He starts at a very simple level in the beginning and slowly builds on it throughout the book and I actually learned a lot despite never taking a physics class. I just took it one page at a time and made sure I understood everything I read before moving on to the next page. I would definitely reread this and take some more detailed notes