Our mathematical universe

What's it about?

Max Tegmark, a renowned Swedish cosmologist, works at MIT, has been interviewed by Morgan Freeman, and collaborates with major figures like Hugh Everett, one of the pioneers of the many-worlds theory. Moreover, Tegmark is listed among the 100 most influential people in AI according to Time.

This book explores the bold idea that the universe is a mathematical object. Tegmark goes beyond merely describing physical phenomena with mathematics: he argues that mathematics doesn't just describe reality, it is reality. He suggests that mathematical concepts exist independently of matter or consciousness perceiving them. According to him, all mathematical structures exist, and among them, one represents our universe, complex enough to contain conscious agents like us.

While this hypothesis is radical, it could solve many problems in physics. However, Tegmark acknowledges that demonstrating this theory experimentally is difficult, if not impossible, to prove or disprove. Some aspects of it are unfalsifiable, making the final chapters of his book feel closer to science fiction than pure science. Nevertheless, it presents a reflection on the world that, while challenging the imagination, opens up fascinating perspectives.

This book straddles the line between non-fiction and fiction. Just as Bernard Werber sprinkles his fictional tales with scientific reality, Tegmark sprinkles reality with his boundless imagination.

What I liked

• Tegmark clearly distinguishes between established, widely accepted science and his more speculative conjectures.
• Discussing parallel universes always has an irresistible appeal.
• Clear diagrams help make the most complex concepts accessible.

What I disliked

• The final third is dense and requires more time and effort to digest than the beginning.
• The concept of a mathematical universe is mind-boggling. Surprisingly, there are few philosophical implications discussed, which leaves a disorienting impression.

Notable Quotes

If the mathematical universe hypothesis is true, this is big news for science, because it opens up the possibility of an elegant unification of mathematics and physics, leading us to understand reality more deeply than we ever hoped. I believe that the theory of a mathematical multiverse is the best theory we could wish for.