Time by Heather Dyke (Cambridge University Press, 2021).

The topic of this book is vast. The author Heather Dyke has less than 80 pages to expound on the nature of time. Her starting point is the distinction between the common-sense conception and the scientific conception of time. The former includes two points: a special present moment and the understanding that time is dynamic. The latter eschews both points. Time begins with a brief historical exposition on the competing stances in the metaphysics of time. Dyke contrasts the Eleatic antichange view with Heraclitean realism about change. McTaggart’s challenge to the reality of time is mentioned and his standard distinction between the A-series and the B-series is discussed throughout the work. Dyke introduces two philosophical tendencies that are in tension. On the one hand, there is the third-person conception of the world, which aims at a subject-neutral characterization of reality. On the other hand, there is the first-person conception of the world, which is about a subjective-relative understanding. In virtue of this distinction, Dyke pursues a top-down analysis of time: ‘Our aim should be to resolve this tension by achieving an understanding of time as it is independently of us, which also accommodates and explains our experience of, and perspective on, time’ (p. 3). Her preferred metaphysics centres on the B-theory. The folk theory of time privileges the present. Whereas one might think that the place ‘here’ is dependent upon a specific location, and hence that it is essentially perspectival, the time ‘now’ is thought to exist independently of location. The absolute ‘now’ is not all that exists, as in that case we could not experience a changing world. There must be change as to what time is ‘now’. There is a continuous transformation between future, present, and past. This aspect is captured by notions like ‘Time marches on’ and ‘Time flows’. Dyke acknowledges that there are other features in the folk conception of time, but takes temporal passage as its central feature. When considering scientific approaches to time, Dyke starts with physics. It is evident that this science, and what it tells about time, has changed in the course of history. Yet she notes, in reference to Callender (2017), that whether we deal with Aristotelian, Newtonian, relativistic, or quantum physics, the ‘now’ has no