Presentism and Passage
Sydney :: Friday 6 May 2005
Click on titles for abstracts.
The Truth About the Past and the Future
This talk is about the truthmaker objection to Presentism. I will offer a reply to the truthmaker objection that has not been much discussed yet. The basic idea is that true propositions about the past and the future are made true by the way things (including the laws of nature) presently are. I will also discuss a potential problem with the formal semantics that go with my proposal, and I will show how that problem can be solved.
Temporal Representations and the Ontological Nature of Time
In an early incarnation the debate about the ontological status of tense had a structure common to many metaphysical disputes. They begin with existential questions: Are there Fs? One party to the dispute holds that there are Fs, and appeals to our ordinary language representations of reality, that involve apparent reference to Fs, to support it. The other party denies that there are Fs, and employs the method of paraphrase to show that apparent reference to Fs can be eliminated so that we are not committed, by the nature of ordinary language, to the existence of Fs. The debate over the ontological status of tense exemplified this structure, with one side, the A-theorists, arguing that our ordinary tensed sentences commit us to the existence of tensed facts, and the other side, the B-theorists, attempting to eliminate apparent reference to tensed facts using the method of paraphrase. However, in the early 1980s, this debate radically changed. A new position emerged in two distinct stages. The truth-conditional variant of the new B-theory, I will argue, showed that the original two positions were not exhaustive, as had been thought. However, it too was guilty, at some level, of confusing semantics with metaphysics. The truthmaker variant, on the other hand, successfully avoids reading its metaphysics off language. I will also show that the very possibility of advancing this position depends on rejecting a particular, flawed view about the relationship between temporal language and temporal reality.
Backwards Causation, Time and the Open Future
Here is an intuitive view about space-time. There is something substantially different about past, present and future locations in space-time. What is definitive of past temporal locations is that the events at those locations are fixed: nothing can change the past. What is definitive of future temporal locations is that events at those locations are not fixed: it is genuinely indeterminate which events will occur in the future. What is definitive of present temporal locations is that they mark the objective ontological border between past locations and future locations, and by doing so they instantiate a particularly salient phenomenological property of 'nowness'. Call the combination of the views according to which there exists an objective present, a fixed past and an open future, the intuitive view. I argue that given the intuitive view, the possibility of backwards causationand hence, for instance, backwards time travelis extremely problematic, if not incoherent. A proponent of the intuitive view must accept one of three deeply counterintuitive consequences as a result of embracing backwards causation. He must say either (i) causation is metaphysically indeterminate: at the time t at which some event E occurs, it is indeterminate whether some future event C causes E, while at t*, the time at which C occurs, it is determinate that C causes E, or (ii) it is determinately the case at t, that E is not caused by C, and it is determinately the case at t*, that E is caused by C or (iii) backwards causation is only possible in cases where it is determinate that C will exist: C exists on all future possible branches. Since none of (i)-(iii) are plausible, I conclude that the intuitive view is inconsistent with backwards causation.
Just Passing Through: Passage in a Block Universe
McTaggart's argument against temporal passage is far more convincing than his argument that passage is essential to the existence of time. If it were not, we would still be arguing about the metaphysical status of time itself rather than the status of passage. An interesting recent development is the emergence of views that implicitly reject not (only) McTaggart's requirements for the existence of time, but (also) his requirements for the existence of passage. These proposals, motivated by respect for contemporary physical theories of spacetime, are concerned with preserving genuine passage within a block universe. In this paper I argue that they all fail. I divide the proposals into two classesinflationist, which aim for a form of passage close to McTaggart's requirements; and deflationist, which aim for a weaker form of passage. I argue that inflationists face insurmountable difficulties, to which the only recourse is a collapse into deflationism; and that deflationism is nothing but a soothing, though metaphysically inert, gloss on the standard block universe. I conclude that McTaggart's requirements on passage are still intact, and still incompatible with the block universe.
Your Actual Eternalism, Without Metaphysics
Presentists and eternalists claim to disagree about what exists. Presentists say that there exist no dinosaurs or human inhabitants of Mars, even if there were or will be such things. Eternalists say that these past and future creatures are as real as we our (present) selves are. However, some philosophers ("skeptics") have argued that the presentist-eternalist disagreement is merely verbal, turning on the fact that the two sides use "exists" in different sense (roughly, a tensed and an untensed sense, respectively).
Presentists thus have two kinds of opponents, eternalists and skeptics. They sometimes try to embarrass both opponents by comparing presentism to actualism, the view that only the actual world exists. Eternalism thus gets compared to the view that all possible worlds are equally real ("possibilism"), and skepticism to the view that there is no real disagreement between actualists and possibilists.
For my part, I'm unembarrassed to embrace skepticism about the existence of an interesting metaphysical disagreement in both arenas. However, I don't think that such skepticism is necessarily even-handed between presentism and eternalism, or actualism and possibilism, nor that the presentism and actualism necessarily fall on the same side of the fence. In this paper I argue that there are pragmatic reasons to privilege both eternalism and actualism, without regarding either dispute as genuinely metaphysical.
The paper was written as a response to a paper by Ted Sider, at a colloquium at the Eastern Division APA Meeting in Boston, December 2004. The latest version of Sider's paper is available here [PDF].
Last updated: 1 May 2005