Modal Realism with Modal Tense

Modal realists should fashion their theory by postulating and taking seriously the modal equivalent of tense, or modal tense. This will give them a uniform way to respond to five different objections, one each by Skyrms, Quine, and Peacocke, and two by van Inwagen, and suggest a non-Lewisian path to modal realism. 0. Introduction The extensive parallel between temporal logic and modal logic has been widely and routinely acknowledged. This naturally raises the expectation that satisfactory metaphysical theories of temporality and modality will parallel each other accordingly. The methodologically pregnant part of this expectation encourages modal metaphysicians to look to the metaphysics of temporality for guidance. A number of prominent modal metaphysicians in fact recommend such 2 It is customary to characterize modal realism along the following lines: (1) there are merely possible worlds, as well as the actual world, (2) there are possible individuals existing at those worlds, and (3) the possible individuals existing at merely possible worlds are as real as those existing at the actual world. I avoid such a characterization because I do not accept (1) and (2) unconditionally. I find the use of the existence predicate ‘there are’ in them problematic. I do not agree with David Lewis’s claim, with which many others concur, that the existence predicates (‘there are’, ‘exist’, and ‘there exist’) have a unique absolutely unrestricted reading. (See section V, sub-section 4 and section VI.) My view is that no absolutely all-inclusive domain is available to legitimize such a reading and therefore every occurrence of an existence predicate needs to be understood relative to a restricted domain. Each of (1) and (2) is true relative to some restricted domains and false relative to others, and ontologically serious discussion of those domains will already involve live issues between modal realists and their rivals. The only widely known and widely discussed modal realist theory is David Lewis’s but my characterization of modal realism allows other versions of modal realism. See Section VII. 2 a general methodological outlook [Kraut 1979, 1980; Adams 1986; Zalta 1987; Lycan 1994: 36; Sider 2001; Markosian 2004], while others refuse to be impressed by the metaphysical implications of the parallel between temporal and modal logics [Lewis 1986; Divers 2002; King 2003]. Modal realism is any theory that postulates possible worlds as real in such a way that merely possible individuals existing at merely possible worlds are as real as actual individuals existing at the actual world. (Actual individuals existing at the actual world are assumed to be fully real.) My aim is to argue for the conditional claim that if the methodology of the fans of the parallel is adopted to implement a certain way of theoretical locution, which involves what I call modal tense, then modal realists will reap benefits. I take this to mean that modal realists should adopt the methodology and be modal tensers. My advice to modal realists that they should be modal tensers is a recommendation concerning their theoretical locution. But it is not merely a recommendation to use certain words. Words express concepts. To accept a certain kind of locution and not others commits one to