Book Review: Reality Is Not What It Seems — The Road to Quantum Gravity

ByGeorges Lteif

1. Who Should Read “Reality Is Not What It Seems — The Road to Quantum Gravity“

Having read Reality Is Not What It Seems — The Road to Quantum Gravity twice, I believe it is a worthwhile read for any science enthusiast interested in physics, Quantum Mechanics, the Theory of Relativity in general and Loop Quantum Gravity in particular.

Much like many of Rovelli’s popular science books, I found the material skinny, often hovering around the subject from a distance and occasionally presenting exceptional insights. These brilliant insights, however, make this book an enjoyable read.

2. Themes

  • Electromagnetism and Maxwell’s field theory
  • Light and photons
  • Quantum Mechanics
  • Special and General Theory of Relativity
  • Spacetime and gravitational fields
  • Quantum Field Theory
  • Space Quantisation
  • Feynman diagrams
  • Planck scale
  • Spin networks
  • Loop Quantum Gravity and its experimental verification

3. What Is Great About “Reality Is Not What It Seems“

If between two things, there is nothing, Aristotle reasoned, then there is nothing. How can there be at the same time something (space) and nothing? What is this empty space within which particles move? Is it something or is it nothing? If it’s nothing, it doesn’t exist, and we can do without it. If it’s something, can it be true that its only property is to be there, doing nothing?

— Carlo Rovelli, Reality Is Not What It Seems

  • Authority: Dr Carlo Roverlli is an expert on Loop Quantum Gravity and is the best person to discuss it in a popular science book.
  • Originality: Loop quantum gravity is not a common topic and is one of the frameworks that allows the unification of Einstein’s theory of relativity with quantum mechanics. The other framework is String Theory, which is superbly presented in David Peat’s book Superstrings and the Search for the Theory of Everything. The ideas on the quantisation of space, the non-existence of a time variable on the smallest scales (the story of Galileo and the chandelier), and the resolution of the infinities problem were brilliant.
  • Writing style: Rovelli’s style is smooth and flowing, making the book an enjoyable and easy read.

4. What Was Not Great About “Reality Is Not What It Seems“

But it is also difficult to understand how to interpret this equation [Wheeler-DeWitt], to know what it means. Among its disconcerting aspects is the fact that it no longer contains the time variable.

— Carlo Rovelli, Reality Is Not What It Seems

  • Content: The book contains much less physics material than I was expecting. Rovelli seems to have decided to sacrifice precision and rigour in favour of accessibility. This would have made sense if this was an introductory book on quantum mechanics or general relativity. The final chapters on the experimental verification of Loop Quantum Gravity and the philosophy and nature of science were sketchy.
  • Conciseness: The book goes off on too many tangents on Greek philosophy, Greek science, and Greek philosophers than what is strictly relevant to the story. These served as distractions rather than guides to the story Rovelli was trying to tell.
  • Accessibility: Half the book is dedicated to classical mechanics, relativity theory, and quantum mechanics. The other half presents Loop Quantum Gravity. The first half is sketchy, not enough, in my opinion, for someone who is not already familiar with the topics, in which case, you feel like you just want to skip through to the interesting chapters. For example, the concept of an extended present would be tricky to digest if you are unfamiliar with lightcones and spacetime geometry.

5. Alternative Recommended Reads

The interested reader has a few options regarding either String Theory or Loop Quantum Gravity. In particular, we found Superstrings and the Search for the Theory of Everything by David Peat to be a fantastic exploration of String Theory. Dr Lee Smolin’s work titled Three Roads to Quantum Gravity is also highly recommended.

A third book is also on my shortlist, and I have high expectations: Dreams of a Final Theory by Steven Weinberg. Finally, The Character of Physical Law by none other than Richard Feynman is a fantastic exposition of the nature of physical laws and the philosophy of science.

6. Short Biography of the Author

Carlo Rovelli, born on May 3, 1956, in Verona, Italy, is a prominent theoretical physicist renowned for his contributions to quantum gravity and efforts in popularizing science. Rovelli obtained his PhD in 1986 from the University of Padua, under the guidance of Abhay Ashtekar, where he focused on the loop quantum gravity approach.

His significant work includes the development of loop quantum gravity, a theoretical framework seeking to reconcile general relativity and quantum mechanics. Rovelli has published numerous research papers and co-authored the seminal work “Loop Quantum Gravity,” contributing substantially to advancing our understanding of the fundamental nature of space and time.

Apart from his contributions to theoretical physics, Rovelli is widely recognized for his role as a science communicator. He has authored several books, including the acclaimed “Seven Brief Lessons on Physics” and “The Order of Time.” These publications distil complex scientific concepts into accessible narratives, catering to a broader audience and fostering an appreciation for physics.

Rovelli’s engaging writing style and ability to convey intricate scientific ideas to the layperson have made him a popular figure in the realm of science communication. Through his books, lectures, and media appearances, he continues to bridge the gap between the scientific community and the general public, making profound concepts in theoretical physics more comprehensible to a wider audience.

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