Lee Smolin — Theoretical physicist and co-inventor of loop quantum gravity, known for contributions to cosmology, quantum foundations, and the philosophy of science. Author of The Trouble with Physics and Einstein's Unfinished Revolution.
The gist
Lex Fridman talks with theoretical physicist Lee Smolin about the deepest questions in physics: what is real, what is time, and what is space. Smolin defends realism, the belief in an objective world independent of perception, and argues that time and causality are fundamental while space is merely emergent. He explains the unfinished revolution begun by Einstein, the gap between quantum mechanics and general relativity, and the measurement problem. The conversation also covers the sociology of physics, the many-worlds interpretation, his critique of string theory, and his idea of cosmological natural selection.
Big reveals
- Smolin says he does not believe there is a scientific method, citing philosopher Paul Feyerabend.
- He claims it is 'probably much worse' than God playing dice: he thinks the fundamental laws of physics can change over time.
- Smolin states time is fundamental and 'goes all the way down,' while space is not fundamental but emergent.
- He asserts the future does not exist; only the present and past are real.
- He admits the many-worlds interpretation does not appeal to him and does not answer the questions he cares about.
- He reveals The Trouble with Physics was originally a methodology book, flipped to lead with string theory on a publisher's suggestion.
- Smolin says his critique of string theory applies equally to his own quantum-gravity community, which he regrets not stating explicitly.
Things worth remembering
- Smolin cites Eric Weinstein's observation that no one thought to put wheels on luggage for centuries despite it being right in front of everyone.
- Quantum entanglement lets two particles share a property that belongs to neither particle individually.
- Bell's locality inequality has been tested and found to fail 'by many sigma' in experiments with photon pairs.
- Smolin says Sean Carroll told him something in June 2016 that changed his whole approach to a problem, but he must tell Sean first.
- Smolin borrowed the concept and the word 'landscape' from theoretical biology to describe how the universe could evolve.
- His idea of cosmological natural selection proposes universes reproduce and evolve toward maximizing fitness, yielding testable predictions.
- Einstein's method was to first discover principles, then build models applying them to experimental situations.
- Young physicists are increasingly uninterested in tribal loops-vs-strings arguments and want unified quantum-gravity conferences.
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The Trouble with Physics
Lee Smolin
“he's the author of several books including one that critiques the state of physics and string theory called the trouble with physics” — Lex Fridman 00:00:00Find it on Amazon
Einstein's Unfinished Revolution: The Search for What Lies Beyond the Quantum
Lee Smolin
“his latest book Einsteins unfinished revolution the search for what lies beyond the quantum” — Lex Fridman 00:00:00Find it on Amazon
The Life of the Cosmos
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“when I first book in 1997 the life of the cosmos was explicitly about that and I was very clear that what was important” — guest 01:02:31Find it on Amazon