Tag Archives: Loop Quantum Gravity

BB #78: Relational Theories

I read Three Roads to Quantum Gravity (2001), by Lee Smolin, a theoretical physicist whose thoughtful style I’ve always appreciated. I don’t always agree with his ideas, though. This book is about Loop Quantum Gravity, in which Smolin has invested considerable effort, and that idea I’m utterly neutral on. It does seem to make more sense than string theory.

One notion I have a lot of trouble swallowing (like a cup of coffee with eight lumps of sugar) is the relational view. (As a philosophy, relationism. Al stayed home.) It’s a fundamental aspect of LQG.

But I (and apparently Kant agrees) think Leibniz was wrong.

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BB #77: Smooth Spacetime

I read Three Roads to Quantum Gravity (2001), by Lee Smolin, a theoretical physicist whose thinking I’ve appreciated since I read his 2006 book, The Trouble with Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next.

Three Roads, as the title suggests, is about the efforts to reconcile quantum mechanics and General Relativity, our two best physical theories. String theory is one road, Loop Quantum Gravity (Smolin’s preferred approach) is another. The third road is complete theory reconstruction (such as discussed by Philip Ball in his book Beyond Weird).

None of that is the subject of this post.

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BB #76: The Holographic Theory

I finished reading Three Roads to Quantum Gravity (2001), by Lee Smolin, a theoretical physicist whose general sensibility I’ve always appreciated. I don’t always agree with his ideas, but I like the thoughtful way he expresses them. Smolin brings some philosophical thinking to his physics.

While he added a lengthy Postscript to the 2017 edition, the book is outdated both by time and by Smolin. In 2006 he published The Trouble with Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next, which explored issues in the practice of theoretical physics. But in 2001 he still thought string theory was (at least part of) The Answer.

Almost none of which is the subject of this post.

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Rovelli: Reality Lessons

Sunday I breezed through Seven Brief Lessons On Physics (2014), by Carlo Rovelli. It’s a quick read of only 96 pages that still manages to touch on some of the key aspects of physics.

His much longer book, Reality Is Not What It Seems: The Journey to Quantum Gravity (2014), covers the same territory in greater detail (and greater length: 288 pages). After I finished what amounted to an appetizer, I tucked into the main course. I’m about 30% through it and am enjoying it quite a bit more than I have his work so far.

Both books, but especially the longer one, explore the theory of Loop Quantum Gravity (LQG), of which Rovelli is a co-founder.

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