On the Origin of Time: Stephen Hawking's Final Theory Hardcover – April 11, 2023

After reading Hawking’s *A Brief History of Time*, and Kipp Thorne’s *Black Holes and Time Warps*, I had the impression that Hawking is not only a great scientist but also a deep philosopher of science. He is a rare breed of scientist who combines solid technical skills with profound insights. He is able to see both the forest and the trees. All this with little “ego” to be seen in his writings or in his followers. Hertog’s book confirms these conclusions.Hertog is a student-cum-fellow of Stephen Hawking. He is an outstanding physicist that knows what he is writing about. The book analyzes how scientific debate is motivated by philosophical positions. In particular, the book explains the journey that Hawking traveled from the position of Einstein to that of Lemaître. I will not summarize these positions so as not to spoil your appetite to read the book! It is an interesting journey that is worth the struggle.The book elegantly weaves scientific theories with the history of science. The style and prose are simple and clear.The discussion of time is subsumed into the discussion of quantum holography. The author emphasizes that spacetime and gravity are “emergent phenomena.” “Holography ingrains a fundamental element of emergence into the very roots of physics—into the fabric of spacetime itself.” According to the author, “Holographic cosmology excises the multiverse like Ockham’s razor.” An important insight is that “there is an upper bound on the amount of information that black holes can store.” In contrast, “multiverse cosmology assumes that our cosmological theories can contain an arbitrarily large amount of information without affecting the cosmos they describe. But holographic cosmology paints a very different picture.”The last chapter is mostly philosophical. The main message is that we ought to be “At Home in the Universe.” This is quite enlightening. But the discussion overall is not as stimulating as the rest of the book. The author probably needs to take another look at that chapter.Overall, despite the many books on black holes, relativity, and quantum physics, this book presents a unique perspective. It also shows the profound value of Hawking’s contributions to modern science and philosophy.

I have read a number of similar books over the years, and this is by far the best one. Not only is it cutting edge, the author knows what he is talking about and knows how to explain it. Very clear cut, but it helps if you have a basic understanding of science and are a visual thinker. Until I read this book, I had problems grasping and accepting some of the new ideas in cosmology until the author explained them logically in a way that made perfect sense. I really loved that some of the new things I was reading in the book agreed with some of my insights which was an immense joy to show to my sons who think their dad is crazy.Buy the hardcover, this one is a keeper that you will want to go back to for reference and review. I believe this book may very well be the zenith of general market cosmology books.

Most books on physics for the layman must include some history; ideas in science are built on the shoulders of historical giants (and a few dwarves). Thomas Hertog does a good job of including the background necessary for his tale without digressing too much. But like all physicists who write such books, his greatest challenge is to translate the Hawking team's work from the language of physics -- complex mathematics -- into language composed of words. He does quite well, I think.I felt there was perhaps a little too much bashing of the Anthropic Principle (AP). In it's simplest form the AP is a tautology: humans cannot find themselves in a universe where the physical laws make it impossible for life to exist, and therefore we see a universe in which the laws are compatible with us. I think Hertog's (and Hawking's) objection to the AP is that, when coupled with a cosmology which posits multiple universes, it appears to make cosmology untestable -- scientifically moot and therefore somewhat useless. I'm not entirely convinced; there have been hypotheses considered similarly untestable which clever investigation has found ways to test experimentally. But others besides Hertog and Hawking have voiced these concerns about the AP and a multiverse, so I can't ding them too much.While most cosmologies start as far back into the origin of our Universe as possible and then find equations to describe how its physics evolved from there, Hawking's idea here is to start with the known physics of our Universe and work backwards to derive a mathematical framework -- a wave function of the Universe -- describing how it began. He calls it a "worm's-eye view" instead of a "god's-eye view", meaning visualizing our Universe from the inside rather than from a god-like "outside". In Hertog's telling, taking the known physical laws as initial parameters for the math gives a different formulation of the wave function than starting with the Big Bang and evolving the equations from there. When worked this way, according to Hertog (and Hawking), the equations end up quite descriptive of our Universe. I'm not at all competent to address the real physics here, though. For laymen such as myself, it's crucial to remember that Hawking, Hertog, and their team worked rigorously inside the mathematical framework of physics. Their proposal had to fit with the math of General Relativity, quantum field theory, etc. It's not just something they dreamed up over pizza and a few beers. At one point Hertog mentions that a photo in the book shows some of their early equations on a blackboard behind Stephen Hawking. I wish he had emphasized the mathematical process more.Overall, it's another interesting and challenging idea from the workshop of Stephen Hawking. I know I've sold "Origin" short in many respects. I only hope I haven't misstated its thesis.Excellent reading to complement "The Origin of Time" would be Brian Greene's "The Hidden Reality", which explains the inflationary multiverse and other cosmological hypotheses. And of course Hawking's "A Brief History of Time", which gives an overview of cosmology, and of Hawking's prior no-boundary proposal. The no-boundary proposal as originally stated by Hawking was disappointing (according to Hertog) because it predicted a universe quite unlike ours; the proposal in "The Origin of Time" works backwards to the no-boundary condition and, as mentioned, appears to give a much better description of our Universe. And for those who don't know deep physics but would like a view into the equations, the indefatigable science author Sean Carroll is writing a trilogy of books to do just that. The first is "Time, Space, and Motion", dealing with classical physics equations from Newton to Einstein; the second (coming in May, 2024) is "Quanta and Fields"; and the third will be "Complexity and Emergence". Keep reading.Incidentally, I bought a paperback copy of "Origin", and got about 2/3 of the way through before the glue in the binding failed. Glued it back together and continued, of course. But disappointing.