Appeals to the ‘common sense’, or ‘naïve’, or ‘folk’ concept of time, and the purported phenomenology as of time passing, play a substantial role in philosophical theorising about time. When making these appeals, philosophers have been content to draw upon their own assumptions about how non-philosophers think about time. This paper reviews a series of recent experiments bringing these assumptions into question. The results suggest that the way non-philosophers think about time is far less metaphysically demanding than philosophers have assumed.

Many physicists have thought that absolute time became otiose with the introduction of Special Relativity. William Lane Craig disagrees. Craig argues that although relativity is empirically adequate within a domain of application, relativity is literally false and should be supplanted by a Neo-Lorentzian alternative that allows for absolute time. Meanwhile, Craig and co-author James Sinclair have argued that physical cosmology supports the conclusion that physical reality began to exist at a finite time in the past. However, on their view, the (...) beginning of physical reality requires the objective passage of absolute time, so that the beginning of physical reality stands or falls with Craig's Neo-Lorentzian metaphysics. Here, I raise doubts about whether, given Craig's NeoLorentzian metaphysics, physical cosmology could adequately support a beginning of physical reality within the finite past. Craig and Sinclair's conception of the beginning of the universe requires a past boundary to the universe. A past boundary to the universe cannot be directly observed and so must be inferred from the observed matter-energy distribution in conjunction with auxilary hypotheses drawn from a substantive physical theory. Craig's brand of Neo Lorentzianism has not been sufficiently well specified so as to infer either that there is a past boundary or that the boundary is located in the finite past. Consequently, Neo Lorentzianism implicitly introduces a form of skepticism that removes the ability that we might have otherwise had to infer a beginning of the universe. Furthermore, in analyzing traditional big bang models, I develop criteria that Neo-Lorentzians should deploy in thinking about the direction and duration of time in cosmological models generally. For my last task, I apply the same criteria to bounce cosmologies and show that Craig and Sinclair have been wrong to interpret bounce cosmologies as including a beginning of physical reality. (shrink)

According to the No Alternate Possibilities argument, if time passes then the rate at which it passes could be different. Thus, time cannot pass, since if time passes, then necessarily it passes at a rate of 1 second per second. One response to this argument is to posit hypertime, and to argue that at different worlds, time passes at different rates when measured against hypertime. Since many A-theorists think we can make sense of temporal passage without positing hypertime, we pursue (...) a different response. We describe several worlds that do not contain hypertime, but do contain differential passage: worlds where time passes at different rates in different subregions within the same world. Hence we argue that even if we focus just on the set of worlds that do not contain hypertime (whether this is all, or only some of the worlds) we find that not all these worlds are such that time passes at a rate of 1 second per second. Thus the No Alternate Possibilities argument fails even when restricted to just this set of worlds. (shrink)

Eternalism is the view that all times are equally real. The relativity of simultaneity in special relativity backs this up. There is no cosmically extended, self-existing ‘now.’ This leads to a tricky problem. What makes statements about the present true? I shall approach the problem along the lines of perspectival realism and argue that the choice of the perspective does. To corroborate this point, the Lorentz transformations of special relativity are compared to the structurally similar equations of the Doppler effect. (...) The ‘now’ is perspectivally real in the same way as a particular electromagnetic spectrum frequency. I also argue that the ontology of time licensed by perspectival realism is more credible in this context than its current alternative, the fragmentalist interpretation of special relativity. (shrink)

The aim of this doctoral dissertation is to closely explore the nature of Einstein’s block universe and to tease out its implications for the nature of time and human freedom. Four questions, in particular, are central to this dissertation, and set out the four dimensions of this philosophical investigation: (1) Does the block universe view of time follow inevitably from the theory of special relativity? (2) Is there room for the passage of time in the block universe? (3) Can we (...) distinguish past from future in the block universe? (4) Is there room for human freedom in the block universe? Although the answer of most philosophers would be yes, triple no, my own answer, controversially, is no, triple yes. -/- I thereby challenge the status quo with respect to each of these metaphysical questions, and argue that none of these questions can be answered from looking at physics alone. Physics may constrain our metaphysics, but it certainly does not settle it. What is needed in order to answer these questions, are additional metaphysical assumptions that fall outside the scope of modern physics. My primary goal in this dissertation, therefore, is not to settle the debates on the nature of time and human freedom, but to clarify them by expliciting the metaphysical assumptions that are otherwise left implicit. (shrink)

In a recent article, Ned Markosian gives an argument against four-dimensionalism understood as the view that time is one of four identical dimensions that constitute a single four-dimensional manifold. In this paper, I show that Markosian attacks a straw man as his argument targets a theory known to be false on empirical grounds. Four-dimensionalism rightly conceived in no way entails that time is identical to space. I then address two objections raised by Markosian against four-dimensionalism rightly conceived.

La philosophie contemporaine du temps voit s’affronter deux conceptions du temps : celle du devenir qui identifie la réalité naturelle à un présent en constant renouvellement et celle de l’univers-bloc qui assimile la réalité naturelle à un espace-temps étendu dans quatre dimensions. Cette dernière approche implique notamment que les événements qui nous semblent passés et futurs sont tout aussi réels que les événements présents et que les êtres humains, bien que mortels, sont des êtres éternels. L’auteur défend cette théorie de (...) l’univers-bloc en montrant que le raisonnement philosophique et les avancées les plus récentes de la physique contemporaine s’accordent à montrer que ce monde quadri-dimensionnel est bel et bien le nôtre. (shrink)

Eternalism is a metaphysical view regarding the nature of time. It posits the equal existence of all times: the past, the present, and the future. Every event, from the big bang to the heat death of the universe, including our births and deaths, is equally real. -/- Under standard eternalism, temporal locations are somewhat akin to spatial locations. No place is exclusively real. When someone says that they stand ‘here’, it is clear that the term ‘here’ refers to their position. (...) ‘Back’ and ‘front’ exist as well. Eternalists stress that ‘now’ is indexical in a similar way. It is equally real with ‘past’ and ‘future’. Events are classified as past, present, or future from some perspective. -/- Eternalism is contrasted with presentism, which maintains that only present things exist and with the growing block view (also known as possibilism or no-futurism), which holds that past and present things exist but not future ones. The moving spotlight view suggests that all times exist but that the present is the only actual time. This view can be termed eternalist, but it preserves a non-perspectival difference between past, present, and future by treating tense as absolute. Additionally, the moving spotlight view retains some characteristics of presentism by maintaining that the ‘now’ is unique and privileged. -/- Broadly speaking, presentism is a common-sensical view, and so aligns with our manifest image of time. This view is, however, at odds with the scientific image of time. The primary motivation for eternalism arises from orthodox interpretations of the theories of relativity. According to them, simultaneity is relative, not absolute. This implies that there is no universal ‘now’ stretched out across the entire universe. One observer’s present can be another’s past or future. Assuming the universe is four-dimensional spacetime, then all events exist unconditionally. -/- The classical argument for eternalism was devised in the 1960s by Rietdijk in 1966 and Putnam in 1967, with subsequent follow-ups by Maxwell in 1985, Penrose in 1989, and Peterson and Silberstein in 2010. This argument and its ramifications remain the subject of ongoing debate. They shall be further explored in this entry, including their relation to other issues in the metaphysics of time and the philosophy of physics. (shrink)

The debate between Einstein and Bergson is a salient episode in the history of modern physics and a telling example of the interaction between science and philosophy. This paper initially discusses five reasons why Bergson criticised Einstein for giving up absolute time. The most important one was Bergson’s commitment to an intuitionist, anti-Kantian metaphysics informed by common sense. Apart from that, he knew that the theory of special relativity permits “duration” in the form of the passage of proper time, to (...) which Bergson referred as “real time”. Neither static eternalism nor dynamic eternalism are acceptable from Bergson’s philosophical perspective, which acknowledges the role of temporal experience and everyday thinking in addition to science and metaphysics. He understood temporal passage as creation of new existence, anticipating what later became known as the growing block theory of time. The pointy relativistic variant of this theory, which divides the universe into blocks of growing past light cones, does justice to large parts of his philosophy, including the distinction between the actual and the virtual. Supporters of Bergson’s account of duration should adopt this theory of time. (shrink)