The Many Lives of Time: On Joseph Mazur’s “The Clock Mirage”

Joseph Mazur | The Clock Mirage | Yale University Press | April 2020 | 272 Pages

In 1922, Albert Einstein and Henri Bergson went head to head about the nature of time in a heated debate in Paris. During their discussion, Einstein famously declared that "the time of the philosophers does not exist."  Whether we agree with him or not, we can read his attack as a wise anticipation of time’s popular history. Throughout the twentieth century, the public’s fascination shifted away from the philosophical conundrums that had surrounded time since antiquity, turning towards the intricacies that modern physics taught us about its behaviour. Einstein himself did an admirable job in making time’s physics comprehensible, initiating a tradition taken up by Steven Hawking and, most recently, Carlo Rovelli. Indeed, who is not baffled by the strange things that physicists tell us about time? That it slows down close to heavy objects or as we move faster, that it gets trapped in black holes, that its passing might be a by-product of thermodynamics; the list goes on.

This rise of popular accounts of time’s physics demonstrated the power and possibilities of good science communication. It did, however, make us lose sight of some of the most fascinating facets of the science and philosophy of time. For what we mean by “time” cannot be exhausted relying only on the vocabulary at the hand of modern physics. Time has a psychology, a biology, and unique intersections with each and every one of our lives. Bringing together the many meanings and aspects of time, not as a challenge but a complement to picture seen through the lens of physical theory, consequently, has long been an overdue task for popular expositions of the subject. Joseph Mazur’s “The Clock Mirage” has achieved precisely that.

Mazur begins by offering us a brief tour through the many historical attempts at reliably measuring time. His discussion is highly informative and introduces the reader to an issue at heart of the book: concepts and conventions of temporality are required for an effective organisation of individual, communal, and societal “living rhythms.” Mazur’s historical narrative only leaves out one crucial option for improvement, as he pays little attention to the contextual diversity of time cultures. He correctly points out how the modern capitalist world brought us standardised and omnipresent time, emerging as consequences of the nineteenth-century telecommunication and transportation revolutions, as well as the globalisation of industrial factory labor. What, however, does not feature in his narrative are all the pockets of resistance and indifference where communities did not adopt this modern culture of time, which often reached them as a by-product of colonial state-building. In many parts of the world, cyclical or constructivist ideas of time thrive persistently. We should not see this as a weakness of Mazur’s book, who is not a historian but a mathematician and science journalist. After all, he opens up an intersection between time and social organisation that may lead the reader to further trace along the many cultural histories of time.

Following his brief history of time measurement, Mazur provides a discussion of the intellectual challenges at the intersection of time and motion. From Zeno’s paradox to Newton’s bucket, he offers a highly accessible exposition of the thought experiments that philosophers and scientists have been using to grapple with the behavior and nature of time. Together, these examples wonderfully elaborate of one of the most tricky and persistent problem of the philosophy of science and quantitative measurement. While we tend to think of some quantities as continuous, represented by the infinitely divisible intervals of the universe of real numbers, we can only measure them in bits and pieces. Can we ever justify the existence such continuity in nature or is it really just a cognitive tool for scientists? Mazur’s though-provoking presentation of historical opinions on the matter nicely set the floor for the following tour de force through time’s physics. Rather than focussing on the many issues surrounding time in quantum theory and its unification with relativity, he focusses on the secure ground provided by the latter. We leave behind the paradoxes that we met earlier when trying to understand the relationship between time and motion, confronting the best attempt we have yet available as a solution: the unified space-time of Einstein and Hermann Minkowski. Time is not only relative to our reference frames of timekeeping, but we can embed the transformations that occur when moving from one frame to another in a four-dimensional geometrical framework. This relativistic framework, Mazur reminds us, even eludes to such counterintuitive possibilities as time travel!

The strongest chapters of the ‘Clock Mirage’ are the last two, in which we learn how the abstract time of the physicist becomes intermingled with the practical time of everyday life. First, this intersection is presented through the lens of psychology and cognitive science. Our perception of time is not one of neatly separated moments, but rather one of time flowing by. We constantly experience time passing, but we can never pick out the individual precepts that make up its flow. Every supposed instance we focus on slips away and is inseparably intertwined with its preceding and subsequent happenings. Moreover, time perception slows down as we age and is constantly affected by our emotional and cognitive experience. While usually neglected in the physicists’ stories of time, all these little idiosyncrasies are indispensable to account for the semantics of the word “time”! Temporality enters our life not only through perception, however, but is already genetically inscribed into our bodies. Humans are evolutionarily fine-tuned for the cyclical rhythms of light and darkness provided by our solar systems and, nonetheless, surprisingly able in adapting to extreme changes in them. Mazur demonstrates these abilities through a wonderful array of examples, introducing us to captivating  experiments of living in cold caves below mountain ranges and in clock-less social isolation. Moreover, he dives into chronobiology – the biology of time – to explain what this fine-tuning looks like on the molecular level and in the big history of circadian synchronization on earth. Re-synchronizing our biological rhythms, moreover, poses one of the biggest, and most interesting challenge to the sci-fi dreams of once settling on exoplanets.

The most captivating part of The Clock Mirage, however, cannot be located in one specific chapter but is spread across the book. Between Mazur’s scientific and philosophical explorations, we find small interviews and monologues about the temporal experience of the author, long-haul truckers, astronauts, prison inmates, and Olympic sprinters. These thought provoking pieces not only glue together the historical, philosophical, physical, mathematical, psychological, and biological facets of time, but constantly remind us how each of them touches on human life.

Finally, Mazur does return to the big question of the philosophers and physicists in his epiloque. What, after all, is this thing called “time” we measure and model? Instead of providing an answer to the age-old riddle, he suggests that we ought to beg the question. There is no monolithic thing called “time,” it is a myth, a “clock-mirage.” Rather, he suggests, we ought to focus on all the different effects we associate with it, spread as they are across philosophy, the sciences, and everyday life. Begging the big question in this way, Mazur’s book teaches us, leaves us with way more than only one answer.

The Clock Mirage is a fantastically pluralistic exploration of all the phenomena we group together under the label “time”. It offers both a lively introduction the different scientific inquiries into these phenomena and a gripping reminder to the specialist (whether she is a philosopher, physicists, biologist, or psychologist) why time matters, for both the fabric of nature and our shared experience of life.

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