Our Mathematical Universe

-1 to the author's giant ego, -1 to some parts being non-science while presented as science

Pretty interesting. You'll probably learn a lot, assuming you aren't an expert in cosmology already. It's pretty dense, so not the easiest read to get through. I like that the author lays out at the beginning which parts of the book are controversial, and which uncontroversial, at the beginning of the book.

It's arguable that I'll actually hold on to any of the physics discussed in its pages, but good to peer into the mind of a top cosmologist.

Max Tegmark says that there are three stages of any significant physical or mathematical theory - first its insignificance (Einstein's famous papers on special relativity languished for years in relative obscurity before he was propelled to fame), then its controversy (Everett and parallel universes, or even Schrödinger and his equation), and finally acceptance - as much as quantum physics doesn't make ‘sense', it is at more or less a consensus to which an alternative has yet to be found.

This piece is a study of the author's own theory, which I would say is stuck between the first and the second stages (above). To many, it is simply a way of life that math more or less explains the universe and/or multiverse - why, though? Tegmark's simple but highly controversial answer, to which he devoted the book, is that we, as in the entirety of everything there was, is and ever will be, are self-aware parts of a mathematical structure.

To put it even more dramatically, Tegmark says that time is an illusion, and we might as well be living in a Mandelbrot set fractal for all we know. Segregating reality into four parts with humans being in one corner of the lowest level is a sobering thought, to say the least. However, he repeatedly hammers the point that we might be the luckiest creatures in existence, as the existence of a particular reality is not a guarantee for the existence of sentient intelligence as well.

Sprinkled with personal anecdotes which only humanise the staggering conclusions, this is a book meant to be absorbed, not devoured. Reading it in a day might not do it justice, as this has no Math whatsoever, but is still technical enough to get the point across - so you are free to ruminate on the possible conclusions.

I am excited to see where Tegmark's Mathematical Universe Hypothesis (MUH) is going to go, notwithstanding it being proven or disproven (although I would bet on the former). There are very few books that I have read that rekindle my interest in the world around me (such as Asimov, Feynman and Penrose), and this is one of those. A must-read.