This is a book review of On the Origin of Time: Stephen Hawking's Final Theory by Thomas Hertog.
On the Origin of Time: Stephen Hawking's Final Theory, by Thomas Hertog (Transworld), 2023. Pp. 326, 23.4 x 15.2 cm. Price £10.99 (paperback, ISBN 978180499112 1).
Belgian cosmologist Thomas Hertog was one of Hawking's last collaborators; the book was written, at Hawking's request, to popularize their joint work, which goes against some of Hawking's earlier work. Hertog, after working in the USA, France, and Switzerland, returned to Leuven as a professor in 2011 (and is now head of the theoretical-physics group at the department of physics and astronomy). His collaboration with Hawking extended essentially until the latter's death in 2018.
The basic idea of Hawking and Hertog (H&H) is that, similar to biological evolution, the Universe — not just the outcomes of the laws of physics but the laws themselves — is best understood as the contingent result of (quantum) branchings during its history (perhaps influenced by future events), rather than something which one could, at least broadly, derive from first principles, thus going beyond the classical difficulty of computing deterministic outcomes in practice and even beyond quantum indeterminacy. If that sounds vague, then that is because it is, at least to me. Those interested in a short summary (but too long to reproduce here) by Hertog himself can read the section starting with the last third of p. 188.
Hertog does a good job of providing a necessary overview of the history of cosmology, especially since the advent of relativistic cosmology somewhat more than a century ago, with the narrative becoming narrower and deeper as the main topic of the book is approached. I didn't find the book convincing; whether that is the fault of Hertog or my own I don't know. The work of H&H not only goes against some earlier work by Hawking but also takes a definite stance on two rather hotly debated topics, namely the AP and the Multiverse. Despite my reservations, the book succeeds in its goal of presenting the basic idea of top-down cosmology for a more general readership and can be a first step for those interested in the topic — it just shouldn't be the last step as well, but a big jump will be needed between the first and last steps. Other modern ideas such as the holographic principle and the black-hole information paradox are explained well, so it can be a jumping-off point for those interested in modern ideas in quantum cosmology and related fields.