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4.22 AVERAGE
4.22 AVERAGE
I wanted to have to give this book five stars but I couldn’t. I liked the fact that he is presenting his view of physics not yet settled. I liked the references to Democritus and the other ancients. I like the idea of science valuing reliability not certainy. An interesting journey but if the objective of this book is to impart an elementary understanding or appreciation of quantum gravity I’m not sure I wuite got there. I did learn a lot and Rovelli is a great guide to all things quantum. I much preferred his Seven Brief Lessons on Physics.
I love books by Carlo Rovelli, and I will definitely be reading every other book he's written and will write in the future. He writes so beautifully about such big, confusing things. And while I won't even pretend to ACTUALLY understand everything he is trying to explain, I think he does a great job of bringing these huge ideas 'down to Earth' - describing them in ways that us non-physicists can sort of understand.
Beyond just telling us what scientists know today, Rovelli describes what some THINK may be the case, based on current knowledge, despite not yet having any hard evidence. And I think that's my absolute favorite part about books by Rovelli and other researchers; seeing that there is so much left to learn is exciting.
Beyond just telling us what scientists know today, Rovelli describes what some THINK may be the case, based on current knowledge, despite not yet having any hard evidence. And I think that's my absolute favorite part about books by Rovelli and other researchers; seeing that there is so much left to learn is exciting.
Beautiful and easy to understand as always. A great introduction to quantum gravity. First half was a bit basic but the explanation of the current thoughts on quantum gravity (vs string theory) was interesting and challenging.
challenging
informative
inspiring
reflective
medium-paced
This is a departure from most of the current physics/cosmology books I've read, it deals with Loop Quantum Gravity and is a very interesting take on the current state of physics and cosmology with which I was unfamiliar.
As a mathematician, I've never really warmed to physics as a subject, it's frankly to practical for a pure mathematician. In this book, Carlo Rovelli move from physics you knew in school through to mathematics through to philosophy in a very satisfying way.
I can't pretend that I really followed some of the finer points of his thesis, but it seems to be that in the 20th century physics has realised what mathematicians have always known - that discrete objects are pretty much interchangeable as far as doing equations is concerned, as are continuous things, however the two kinds of stuff have really very different properties, so it's important to know which kind of thing you are dealing with. The insight of relativity, quantum etc.. seems to boil down to the idea that you can apply the same set of mathematical equations to space as to time as to particles as to forces which implies they are all discrete. The fact that there is an exception in gravity is not really a mathematical surprise as it could well be the case that it is governed by a continuous function which will always have different rules to discrete quanta - which may mean that the search for a unifying theory in physics is doomed to failure.
The final chapters become a little more speculative and drift off into philosophy positing that actually all these discrete fields are in some essential ways the same thing - "covariant fields" - in a similar way to how Einstein theorised that space and time are actually the same thing and we should more correctly talk about spacetime. In both cases, mathematically, I think there is some more unpacking to be done - just because the same rules can be applied to counting apples and oranges doesn't make them the same thing, or (in a rather more technical analogy), the field of rational numbers is nested within the field of real numbers which is itself nested within the field of complex numbers, the fact that there are a subset of functions (e.g. adding and subtracting) that you can apply to all of these fields and see the same type of consistent predictable algebraic behaviours doesn't make these fields interchangeable or indistinguishable from one another- they are mathematically very much different things with entirely different properties. This is actually a deeper and "truer" truth than the fact that apples and oranges are different things, even though they both happily sit around to be counted and both describe the same parabolic arcs when used as missiles.
Maybe in relativity or quantum loop theory there are valid reasons for concluding that same rules = same thing, but the logic remains somewhat hidden from me.
I can't pretend that I really followed some of the finer points of his thesis, but it seems to be that in the 20th century physics has realised what mathematicians have always known - that discrete objects are pretty much interchangeable as far as doing equations is concerned, as are continuous things, however the two kinds of stuff have really very different properties, so it's important to know which kind of thing you are dealing with. The insight of relativity, quantum etc.. seems to boil down to the idea that you can apply the same set of mathematical equations to space as to time as to particles as to forces which implies they are all discrete. The fact that there is an exception in gravity is not really a mathematical surprise as it could well be the case that it is governed by a continuous function which will always have different rules to discrete quanta - which may mean that the search for a unifying theory in physics is doomed to failure.
The final chapters become a little more speculative and drift off into philosophy positing that actually all these discrete fields are in some essential ways the same thing - "covariant fields" - in a similar way to how Einstein theorised that space and time are actually the same thing and we should more correctly talk about spacetime. In both cases, mathematically, I think there is some more unpacking to be done - just because the same rules can be applied to counting apples and oranges doesn't make them the same thing, or (in a rather more technical analogy), the field of rational numbers is nested within the field of real numbers which is itself nested within the field of complex numbers, the fact that there are a subset of functions (e.g. adding and subtracting) that you can apply to all of these fields and see the same type of consistent predictable algebraic behaviours doesn't make these fields interchangeable or indistinguishable from one another- they are mathematically very much different things with entirely different properties. This is actually a deeper and "truer" truth than the fact that apples and oranges are different things, even though they both happily sit around to be counted and both describe the same parabolic arcs when used as missiles.
Maybe in relativity or quantum loop theory there are valid reasons for concluding that same rules = same thing, but the logic remains somewhat hidden from me.
I wish he had spent much more time on the LQG explanations than he did. What he did explain struck me as being a very mathematical way of looking at reality - not in the sense of equations, but a style of description or thinking. And from that point of view, I liked the definition of the basic constituent of spacetime and of the evolution of time - essentially a graph whose components can interact, and whose very interactions create the phenomenon of time passing. But given that I could describe its essence so compactly, I suspect there's more to it which would have been explainable in a non-jargony way with a little more space - but maybe I'm wrong and that's really it.
Amazing! From a comprehensive overview of natural science's history up to the cutting edge of fundamental physics. I am no physicist, and I don't think this book gave me a clear understanding of the world we live in (what book could possibly?). But let it be clear that this is no criticism. On the contrary, I think Rovelli achieved what he set out to do. He convinced me of the strangeness of the world we interact with. I think the last chapter summarizes this very neatly:
"A scientist is someone who lives immersed in the awareness of our deep ignorance, in direct contact with our own innumerable limits, with the limits of our understanding."
Now I don't consider myself a scientist quite yet, but I think this book did put me in direct contact with our innumerable limits. It certainly made me aware of my deep ignorance. This book is one of the few pop science books written by a distinguished physicist that dares to talk about theories and problems that still lack consensus in the scientific community. It shows us a glimpse, fully aware of the uncertainty of the matters, of today's mysteries and tomorrow's breakthroughs.
Rovelli brings his expertise, presents it so accessibly but simultaneously dripping in childlike passion and excitement.
You'll finish this book dazed and confused, richer with countless new concepts and theories you are only just barely beginning to grasp, but you'll be immersed, impressed and excited. Hungry for knowing how the world works.
"A scientist is someone who lives immersed in the awareness of our deep ignorance, in direct contact with our own innumerable limits, with the limits of our understanding."
Now I don't consider myself a scientist quite yet, but I think this book did put me in direct contact with our innumerable limits. It certainly made me aware of my deep ignorance. This book is one of the few pop science books written by a distinguished physicist that dares to talk about theories and problems that still lack consensus in the scientific community. It shows us a glimpse, fully aware of the uncertainty of the matters, of today's mysteries and tomorrow's breakthroughs.
Rovelli brings his expertise, presents it so accessibly but simultaneously dripping in childlike passion and excitement.
You'll finish this book dazed and confused, richer with countless new concepts and theories you are only just barely beginning to grasp, but you'll be immersed, impressed and excited. Hungry for knowing how the world works.
challenging
informative
inspiring
reflective
slow-paced
Explains something really abstract in a super digestible way. I learned so much from this one. Really fun to get a little high to. Blew my mind a few times.