This book, one of the first full-length studies of the modalities to emerge from the debate to which Saul Kripke, David Lewis, Ruth Marcus, and others are contributing, is an exploration and defense of the notion of modality de re, the idea that objects have both essential and accidental properties. Plantinga develops his argument by means of the notion of possible worlds and ranges over such key problems as the nature of essence, transworld identity, negative existential propositions, and the existence (...) of unactual objects in other possible worlds. He also applies his logical theories to the elucidation of two problems in the philosophy of religion: the problem of evil and the ontological argument. (shrink)

While many are impressed with the utility of possible worlds in linguistics and philosophy, few can accept the modal realism of David Lewis, who regards possible worlds as sui generis entities of a kind with the concrete world we inhabit.1 Not all uses of possible worlds require exotic ontology. Consider, for instance, the use of Kripke models to establish formal results in modal logic. These models contain sets often regarded for heuristic reasons as sets of “possible worlds”. But the “worlds” (...) in these sets can be anything at all; they can be numbers, or people, or sh. The set of worlds, together with the accessibility relation and the rest of the model, is used as a purely formal structure.2 One can even go beyond establishing results about formal systems and apply Kripke models to English, as Charles Chihara has recently argued.3 Chihara shows, for instance, how to use Kripke models (plus primitive modal notions) to give an account of validity for English modal sentences. In other cases worlds are not really needed at all. It is often vivid to give a counterexample thus: “There is a possible world in which P. Since your theory implies that in all worlds, not-P, your theory is wrong.” But the counterexample could just as easily be given using modal operators: “Possibly, P. Since your theory implies that it is necessary that not-P, your theory is wrong.”. (shrink)

Presented here is an argument for the existence of universals. Like Church's translation- test argument, the argument turns on considerations from intensional logic. But whereas Church's argument turns on the fine-grained informational content of intensional sentences, this argument turns on the distinctive logical features of 'that'-clauses embedded within modal contexts. And unlike Church's argument, this argument applies against truth-conditions nominalism and also against conceptualism and in re realism. So if the argument is successful, it serves as a defense of full (...) ante rem realism. The argument emphasizes the need for a unified treatment of intensional statements -- modal statements as well as statements of assertion and belief. The larger philosophical moral will be that ante rem universals are uniquely suited to carry a certain kind of modal information. Linguistic entities, mind-dependent universals, and instance-dependent universals are incapable of serving that function. (shrink)

This paper is part of a general programme of developing and investigating particular first- order modal theories. In the paper, a modal theory of propositions is constructed under the assumption that there are genuinely singular propositions, ie. ones that contain individuals as constituents. Various results on decidability, axiomatizability and definability are established.

This paper presents a bivalent extensional semantics for positive free logic without resorting to the philosophically questionable device of using models endowed with a separate domain of "non-existing" objects. The models here introduced have only one (possibly empty) domain, and a partial reference function for the singular terms (that might be undefined at some arguments). Such an approach provides a solution to an open problem put forward by Lambert, and can be viewed as supplying a version of parametrized truth non (...) unlike the notion of "truth at world" found in modal logic. A model theory is developed, establishing compactness, interpolation (implying a strong form of Beth definability), and completeness (with respect to a particular axiomatization). (shrink)

Presentism is the thesis that only present things exist. This view is to be contrasted with eternalism, the thesis that reality includes past, present and future entities. It is commonly believed that presentism is subject to a number of devastating objections. The central project of this dissertation is to state and answer five of the most widely discussed of these objections. ;I begin with the complaint that presentism is either trivially true or trivially false. I argue that this objection rests (...) on a subtle de re/de dicto confusion, and that once this confusion is sorted out, it's easily seen that presentism is neither. ;Then I discuss the objection from singular propositions: it seems that there are singular propositions about objects which did exist but do no longer, e.g. Lassie was beloved. But on the standard account, singular propositions about x depend on x for their existence, implying that reality is not exhausted by the present. I reply by arguing that, despite its popularity, the standard account of singular propositions isn't very plausible. ;Next, I develop the objection from trans-temporal relations: yesterday's downpour caused today's flooding. Today's flooding, therefore, bears the is caused by relation to certain events which occurred yesterday. But for a relation to hold between two things, both must exist. So it must not be the case that only present things exist, since yesterday's downpour is no longer present. I reply by pointing out that "yesterday's downpour caused today's flooding" might well express truth even if today's flood bears no relation to yesterday's downpour. ;I then spell out the objection from Special Relativity : Minkowskian SR is inconsistent with presentism; so the much the worse for presentism. I answer that the presentist does better by rejecting Minkowskian SR for an empirically equivalent alternative compatible with presentism than by rejecting her presentism for a Minkowski-friendly eternalism. ;I conclude by answering the "truth supervenes on being" objection. Truths about the past require a ground or truthmaker . But surely the totality of present things doesn't make true all truths about the past. I reply that indeed it does. (shrink)

This paper presents a bivalent extensional semantics for positive free logic without resorting to the philosophically questionable device of using models endowed with a separate domain of “non-existing” objects. The models here introduced have only one (possibly empty) domain, and a partial reference function for the singular terms (that might be undefined at some arguments). Such an approach provides a solution to an open problem put forward by Lambert, and can be viewed as supplying a version of parametrized truth non (...) unlike the notion of “truth at world” found in modal logic. A model theory is developed, establishing compactness, interpolation (implying a strong form of Beth definability), and completeness (with respect to a particular axiomatization). (shrink)