whereas there is no concrete object (save, perhaps, a divine concrete object, if such a
being exists) such that it is necessarily true that it always exists.
These arguments go through only if (i) there are real differences between genuinely
logical vocabulary and other expressions and (ii) modal or tense vocabulary is
genuinely logical. Both issues are thorny and difficult, and can’t be addressed here.
For instance, the claim thattense logicis a part of logic seems to me especially
precarious.^60 However, inasmuch as these claims are defensible, the view defended in
this section can be motivated.
2.5.4 Modal Logic II: Actuality and Possibility as Modes of Being
Let’s examine a second attempt at using considerations of modal logic to buttress a
modes of being ontology. In this case, we will consider the difference between the
actual and the merely possible.
Possibilismis the view that there are objects that aremerelypossible. Possibilism
has enjoyed a recent resurgence thanks to the work of David Lewis (1986), who
famously holds that the merely possible are ontologically on a par with the actual.
Possible worlds, on Lewis’s view, are spatiotemporally isolated physical universes,
many of which contain human beings differing from you and me only in that they are
much harder to visit. To be actual, on Lewis’s (1986: 92–6) view, is merely to be
spatiotemporally related to me:actualityis on this picture merely indexical, just like
being here.^61
Despite modal realism’s incredible ontology, there are impressive arguments for it.
But no impressive argument suffices to overcome the following worry, succinctly
stated by Phillip Bricker (2001: 29):
The alternative [to Lewis’s view] for the realist is to hold that actuality is absolute, and that
there is an ontological distinction in kind between the actual and the merely possible. In my
opinion, this is the only viable option for the realist. Our conceptual scheme demands that
actuality becategorical: whatever is of the same ontological kind as something actual is itself
actual. To hold then, as Lewis does, that the actual world and the possible worlds do not differ
in kind is simply incoherent.
Bricker accordingly holds that there is a primitive fact about which things in modal
reality are the actual things. But Bricker (2001: 30) also correctly notes that this fact
cannot consist in some things having aqualitythat others lack.^62 In what then does
this primitive fact consist? The obvious answer is that the merely possible exist in a
fundamentally different way than the actual. There are merely possible things and
there are actual things but the ways in which there are these things differ.
(^60) But for a defense of tense logic as logic, see Geach (1980: 312–18.)
(^61) Lewis’s version of possibilism is the most well known, but there are many ways to be a possibilist. See
Bricker (2001, 2006) and McDaniel (2004, 2006b) for other versions of possibilism. 62
Bricker (2006) sort of takes this back by appealing to“non-qualitative”properties.