Time and Identity

1 Temporal Reality

Nonphilosophers, if they think of philosophy at all, wonder why people work in metaphysics. After all, metaphysics, as Auden once said of poetry, makes nothing happen (Auden 1940). Yet some very intelligent people are driven to spend their lives exploring metaphysical theses. Part of what motivates metaphysicians is the appeal of grizzly puzzles (like the paradox of the heap or the puzzle of the ship of Theseus). But the main reason to work in metaphysics, for me at least, is to understand the shared world that we all encounter and interact with. And the shared world that we all encounter includes us self-conscious beings and our experience. The world that we inhabit is unavoidably a temporal world: the signing of the Declaration of Independence is later than the Lisbon earthquake; the cold war is in the past; your death is in the future. There is no getting away from time. The ontology of time is currently dominated by two theories: presentism, according to which “only currently existing objects are real” (Sider 2001, 11), and eternalism, according to which “past and future objects and times are just as real as currently existing ones” (ibid.).1 In my opinion, neither presentism nor eternalism yields a satisfactory ontology of time. Presentism seems both implausible on its face and in conflict with the special theory of relativity, and eternalism gives us no handle on time as universally experienced in terms of an ongoing now. (There is a third theory, the “growing block universe,” according to which the past is real but the future is not; but it also conflicts with the special theory of relativity.2 ) So, I shall bypass these theories for now and return to them later. This chapter has two parts. Part I aims to develop a way to understand time that is adequate both to physics and to human experience. It begins with McTaggart’s framework of the A-series and the B-series—the framework that underlies both presentism and eternalism.3 I shall set out a theory (that I call “the BA-theory”) that shows how the A- and B-series are related without reducing either to the other. Then, I shall draw out some 1 Temporal Reality Lynne Rudder Baker 28 L. R. Baker metaphysical implications of the view. Part II is a discussion of time and existence; more particularly, it is a discussion of the relation between the temporal world and the nontemporal domain of the unrestricted existential quantifier. I shall argue that the world—though not the domain of the unrestricted existential quantifier—is ontologically different at different times. I The A-Series and the B-Series There are two distinct ways in which we conceive of time: in a “tensed” way, in terms of past, present, and future (“You will be dead in 60 years,” “It’s now 4:00,” “The earth is millions of years old,” “The play has just started”) and in a “tenseless” way, in terms of clock times (“The play starts at 8:00 PM”) and relations of succession and simultaneity (“The sinking of the Titanic is earlier than the beginning of World War I.”) McTaggart named these two ways of temporally ordering events the “A-series” and the “B-series,” respectively.4 Events change with respect to their A-properties (pastness, presentness, futurity). For example, the death of Queen Anne was once in the future, then it was present, then past. So, there are really many different A-series, not just one. By contrast, events do not change with respect to their B-relations (earlier than, simultaneous with, later than). For example, if the signing of the Declaration of Independence is later than the Lisbon earthquake, then the signing of the Declaration of Independence is always later than the Lisbon earthquake. The term ‘tenseless’ refers to the fact that B-relations between events do not change over time: once “earlier than,” always “earlier than.” Although the expressions ‘past’, ‘present’, and ‘future’ are characteristic of the A-series, those expressions may be used to designate B-series relations . For example, ‘in the past’ is an A-series term only if it’s used with a shifting reference—as in ‘The McCarthy era is in the past’, where ‘in the past’ is relative to now. If ‘past’ is used relationally—as in ‘The McCarthy era is in the past in 2005’—‘past’ has nothing to do with the A-series. ‘The past at t’ is a...