Adrian Bardon’s recent book A Brief History of the Philosophy of Time offers a historical, scientific, and philosophical exploration of some of the key issues in philosophy of time, joining the ranks of Travels in Four Dimensions by Robin LePoidevin (Oxford University Press, 2003) and Everywhere and Everywhen by Nick Huggett (Oxford University Press, 2010). It provides a good introduction to traditional topics such as Zeno’s paradoxes, McTaggart’s paradox, temporal passage, and the arrow of time while indicating their relation to broader issues such as the nature of experience, moral responsibility, and personal identity. It also manages to initiate its readers into some of the most interesting contemporary debates in the field. Throughout the book, both historical and contemporary positions are categorized in terms of three recurrent and evolving positions: idealism, realism, and relationism.

The book begins by introducing the connection between time and change—a common point of entry both historically and intuitively. He begins with a discussion of Zeno’s paradoxes of motion (and the resulting idealism) and Aristotle’s relationist response, along with a brief description of how contemporary mathematics contributes to the debate. This is followed by an examination of a lovely fragment from Parmenides, which presents the case for the illusoriness of change. Bardon analyzes this in terms of temporal passage and an event’s evolution from being future, to being present, to being past, foreshadowing issues raised in chapter 4 concerning temporal passage and McTaggart’s paradox. The chapter concludes with a discussion of Augustine, who is sympathetic to idealism yet perplexed by the origin of our ideas of past, present, and future.

In the second chapter, we are introduced to Locke’s empiricism and the trouble it poses for his temporal realism. Since change requires two different, successive states, the source for our idea of change would seem to be two different, successive experiences. Yet those experiences would only be of the individual states, not the change itself. Therefore, it seems that we have no simple and direct experience of change. This problem points toward the formation of Kant’s idealism, which Bardon lays out quite clearly. He then returns to a defense of realism, where he considers the possibility of an extended experienced present that could accommodate a single experience of successive events. The chapter concludes with a consideration of the phi-phenomenon, flash-lag effect, cutaneous rabbit phenomenon, and cross-saccadic perceptual continuity, in order to show the pervasiveness of construction in human perception and the problem this poses for realists.

Chapter 3 attends to competing scientific images of time, beginning with Newton’s absolutism (a form of temporal realism) and Leibniz’s relationism, before offering a clear and nicely illustrated explanation of Einstein’s special theory of relativity (STR). In his explanation of STR, Bardon demonstrates the relativity of simultaneity and the rejection of a unique and privileged present. Lastly, he questions the status of these models of space-time beyond their predictive and explanatory use, introducing scientific instrumentalism and its contrast with scientific realism.

Chapter 4 deals with the topic of temporal passage. Bardon provides a clear account of McTaggart’s paradox, introducing the reader to the A- and B-series and the corresponding dynamic and static theories of time they imply. Drawing on Parmenides’s and McTaggart’s paradoxes, he shows how the determinations of past, present, and future engender contradiction and thus cannot be real features of reality. Next, he returns to the scientific model of space-time found in STR, showing that the relativity of simultaneity removes the possibility of an objective past, present, and future. As it is considered here, temporal passage is reliant on these determinations, so it too must be abandoned as a feature of reality. He balances these logical and scientific criticisms of temporal passage with a section emphasizing the grip that experience has on our way of thinking about time and the difficulty faced by the static theorist in accounting for that experience. In the last section of the chapter he attempts to reconcile the tension between the experiential intuition that time passes and the scientific image of time. It is in this chapter that Bardon exposes the reader to some of the most recent topics of inquiry regarding our temporal experience, including the brain’s construction of dynamic continuity as considered by Sean Kelly, psychological projection as addressed by Robin LePoidevin and D. H. Mellor, the role of our spatiotemporal limitations discussed by Quassim Cassam, and evolutionary considerations explored by James Maclaurin and Heather Dyke.

Chapter 5 focuses on the arrow of time and various attempts to locate the source of this directionality. Bardon gives a clear, nontechnical explanation of both the thermodynamic and causal arrow and shows how explanations for both are dependent on a presumed temporal asymmetry. The psychological arrow is identified as the source for our belief in the direction of time and shown under some accounts to be dependent on the thermodynamic arrow. These considerations lead Bardon to conclude that time itself may have no direction, a conclusion he reinforces with the notion of psychological projection and underscores with the appeal to retrocausation found in Huw Price’s interpretation of certain quantum phenomena.

The final three chapters of the book examine time travel, free will, and the possibility of a beginning or end to time, respectively. Here Bardon addresses the standard problems raised by these topics. In his chapter on time travel, he lays out the distinction between logical, physical, and practical possibility and discusses the grandfather paradox, the double-occupancy problem, and the twin paradox. He effectively brings this all to bear on the debate between the static and dynamic theories, which nicely segues into his chapter on free will. In the chapter on free will he provides a clear and thorough account of various different positions, including logical, metaphysical, and theological fatalism; causal determinism; compatibilism; and libertarianism. He examines the problems faced by each and their proposed solutions. In his chapter on the possible beginning or end to time, he considers Aristotle’s relationism, Kant’s idealism, and modern scientific realism.

In the epilogue, Bardon turns to the apparently fundamental question, “what is time?” Here he returns his focus to the relationship between science and experience and considers the value and inescapability of each. Interestingly, he proposes that the question as posed may be the wrong one, suggesting that “time is not so much a ‘what’ as a ‘how,’ and not so much a question as an answer” (175). Time, for Bardon, is the way we organize our experiences and model events. The discussion concludes with an examination of the ways in which relationism, idealism, and realism each offers helpful insights into the “how” of time.

Bardon’s overall framing of the debates in terms of realism, idealism, and relationism has its advantages and disadvantages. On the one hand, employing these categories serves as a useful pedagogical tool for corralling the various debates and imposing some easily recognizable order on them. On the other hand, casting them in these terms sometimes threatens to distort the actual character of the debates. At the end of the book, he seems to imply that one can pick and choose from the three, acknowledging the relationist idea that our measures of time are necessarily tied to change, espousing idealism in regard to temporal passage and direction, while accepting realism when it comes to models of space-time that have a good deal of explanatory and predictive import.

We see a similar division of labor in chapter 4, where he states, “Our conclusion to the issue of reconciling our perception of time with the logic and science of time must be to accept that there will never be some sort of final unification of experience and reality. Logic and science will tell us one thing about reality, even as our perceptual and cognitive faculties shall—and must—insist otherwise” (110). However, it seems a mistake to draw such a rigid distinction between the picture of the world we get through experience and that which we get through science and logic since, as Bardon acknowledges in the epilogue, all we know of the world is filtered through our experience. It strikes me as a worthy pursuit to attempt to develop a rich and unified understanding of the range of our experiences, from common everyday perceptions to our scientific observations.

In particular, as he points out, scientific explanations appeal to the evolution or dynamic change of a system, and yet this is done against the backdrop of static space-time. His frequent reference to the static account of change as “timeless” ignores the very important role time plays in that account and how often we think of change in terms of it. Perhaps teasing apart the experience of things dynamically changing and the experience of time passing would enable us to give an account of the former that is compatible with the scientific image of time.

Overall, however, this book offers a stimulating look at cutting-edge investigations in temporal experience, while providing a nice introduction to many of the topics found in philosophy of time both historically and currently. Bardon manages to provide the reader with a wide variety of possible solutions to the various questions, while keeping the debates open and engaging.