As an essay in history, this book starts off badly. In the first 25 pages there are four historical errors (on Aristotle, Ptolemy, Galileo and Kepler), anachronistic and naïve interpretations of history, and even a mistake in astronomy. (Mercury, not Mars, has the most eccentric orbit of the five visible planets.)
Thankfully, most of the rest of book is on contemporary cosmology, relativity theory, quantum mechanics, and fundamental particle physics -- the stuff of Ontario scientist Lee Smolin's trade.
Smolin is a theoretical physicist at the famed Perimeter Institute of Waterloo University, working in the forefront of cosmology and the endeavor to link gravity with quantum physics, the so-called unified theory of everything.
Journeying beyond the insular confines of abstruse physics, Smolin has spread his wings by writing non-technical books explaining his ideas on these matters to the scientifically curious reader. This is his fourth book in this genre.
His last book, The Trouble with Physics (2006), was a fervent critique of string theory, one of the major contemporary models of the fundamental structure of matter. In light of the early pages of Time Reborn, a better subtitle of this latest book might have been The Trouble with Physicists Writing History.
Nonetheless, as an essay on contemporary debates in important areas of physics, Time Reborn is up-to-date and chock-full of diverse hypothetical models put forth by a coterie of physicists having a go at discovering the ultimate theory, which, if successful, is an assured route to a Nobel Prize. To be sure, all this is filtered through Smolin's idiosyncratic viewpoint.
In addition to a critique of string theory, another topic that puts him at odds with many fellow cosmologists is his critique of the multiverse model, which has gained credence among cosmologists in recent years. The key concept in this model is that our universe is merely one of possibly an infinite number of universes co-existing at the same time.
Smolin, however, believes we live in only one universe, or, at least, one universe at a time -- one reason being that the multiverse model, as he interprets it, means that time is an illusion. This idea, he argues, is the culmination of a process of eliminating time in physics that goes back to Newton, yet which he believes is wrong. Time, instead, is real: hence Time Reborn.
Despite Smolin's previous efforts to solve the unification puzzle, in Time Reborn he calls off that chase, believing that a more fundamental approach is required to bring real time back into physics. A possible model that accomplishes this is what he calls "cosmological natural selection," in which a universe is created from of a black hole.
In such a model the laws of nature evolve over time -- real time. The evolution of the universe along the so-called arrow of time, as set out in the entropy law of thermodynamics, is further evidence for Smolin of the reality of time.
From a historical and philosophical viewpoint, what is fascinating about this idea is that physics is drawing on methodology from biology rather than the other way around, as in traditional reductionism.
Finally, in his endeavor to eliminate flawed cosmological hypotheses, Smolin repeatedly returns to the principle of sufficient reason, an idea from the 17th-century mathematician-philosopher Gottfried Leibniz.
This idea that nothing in nature can exist without a rational explanation also influenced Einstein who flirted with it as a methodological approach. All of which shows how enduring and recurring are some basic conceptual ways that humans think about the world.
David Topper is senior scholar in history at the University of Winnipeg. His latest book, How Einstein Created Relativity, was recently published by New York-based Springer Publishing.