Online research in philosophy

It is sometimes argued that if God were to exist, then the actual world would be the best possible world. However, given that the actual world is clearly not the best possible world, then God doesn’t exist. In response, some have argued that the world could always be improved with the creation of new people and that there is thus no best possible world. I argue that this reasoning gives rise to an instance of Parfit’s mere addition paradox and should thus be rejected. Others (Robert Adams, in particular) have argued that the actual world may, in fact, be the best possible world, at least for all actual people. I argue that this reasoning gives rise to Parfit’s non-identity problem and should thus be rejected.

0. Relativistic Content In standard semantics, propositional content, whether it be the content of utterances or mental states, has a truth-value relative only to a possible world. For example, the content of my utterance of ‘Jim is sitting now’ is true just in case Jim is sitting at the time of utterance in the actual world, and the content of my belief that Alice will give a talk tomorrow is true just in case Alice will give a talk on the day following the occurrence of my belief state in the actual world. Let us call propositional content which has a truth-value relative only to a possible world ‘non-relativistic content’. Non-relativistic content can be treated as either structured or unstructured. On the unstructured-content view, non-relativistic content is a set of possible worlds and bears the truth-value true just in case the actual world is a member of that set. For example, the content of my utterance of ‘Jim is working now’ at time t is the set of worlds in which Jim is working at t, and this content is true just in case the actual world is among those worlds. On the structured-content view, non-relativistic content is a set or conglomeration of properties and/or objects, where properties are features which objects possess regardless of who considers or observes them and regardless of when they are being considered or observed. Such properties are said to be (or represent) functions from possible worlds to extensions. Relative to a possible world they determine a set of objects instantiating the property. For example, relative to the actual world the property of being human determines the set of actual humans. Not all content is non-relativistic. Let us say that propositional content is relativistic just in case it possesses a truth-value only relative to a centered world. A centered world is a possible world in which an individual and a time are marked, where the marked individual..

– While preparing my suitcase for Padua, I took care to put my favorite cds in a secured spot since they could have broken along the way. Which (non-mental) fact, if any, could possibly justify my action – i.e. what, if anything, makes it the case that my cds could have broken? The paper explores the nature of possibility. The three theories most widely endorsed thus far – fictionism, actualism, and modal realism – are introduced, with a particular attention to their unpalatable ontological consequences. In order to avoid such consequences, a fourth theory is put forward. The goal of the theory is to explain the nature of possibility on the basis of actual (vs possible) entities while, at the same time, providing a non-circular interpretation of the meaning of our modal talk on the basis of such actual entities. Dispositions are meant to be the ontological ground of the theory. They play the role of possibilia – i.e. the entities on the basis of which we interpret modal assertions. A characterization of the sort of dispositions needed for grounding the theory is given. Finally follow some remarks on the effects of the theory upon the extension of the domain of possibilia.

Deep theorizing about possibility requires theorizing about possible objects. One popular approach regards the notion of a possible object as intertwined with the notion of a possible world. There are two widely discussed types of theory concerning the nature of possible worlds: actualist representationism and possibilist realism. They support two opposing views about possible objects. Examination of the ways in which they do so reveals difficulties on both sides. There is another popular approach, which has been influenced by the philosophy of Alexius Meinong. The Meinongian approach is relevant to theorizing about possible objects because it attempts to construct a general theory of objects other than ordinary concrete existing objects. Independently of the debate about the nature of possible worlds or about Meinongianism, it is not always as straightforward as it may at first appear to determine whether putative possible objects are indeed possible. Another category of object similar to that of a possible object is the category of a fictional object. Although initially attractive, the idea that fictional objects are possible objects should not be accepted blindly. An important instance of theoretical usefulness of possible objects is their central role in the validation of two controversial theorems of a simple quantified modal logic.

It has been argued that actualism – the view that there are no non-actual objects – cannot deal adequately with statementsinvolving iterated modality, because such claims require reference, either explicit or surreptitious, to non-actualobjects. If so, actualists would have to reject the standard semantics for quantified modal logic (QML). In this paper I develop an account of modality which allows the actualist tomake sense of iterated modal claims that are ostensibly aboutnon-actual objects. Every occurrence of a modal operatorinvolves the stipulation of a possible world, and nestedmodal operators require stipulation of nested possible worlds.I provide an actualistically acceptable (AA) semantics for QMLwherein the nesting relation is irreflexive and intransitive and forms a tree. Despite these restrictions, AA models can beshown to be sound and complete for a wide variety of modal logics.

Within the general framework of the theory of direct reference, there is no agreement as to whether unactualised possible objects (from now on, possibilia) can be referred to by means of directly referential singular terms (from now on, DR terms). While some have maintained that such a direct reference can be established e.g. via some fixing-reference description (Kaplan, Salmon, and perhaps Kripke himself), others have denied any such possibility. In what follows, I will scrutinise such denials by attempting at the same time to provide some counterarguments to them. Indeed, I believe that possibilia can be referred to directly, primarily if the appropriate fixing-reference description is provided.

The standard Kripkean semantic theories for quantified modal logic allow the individuals that exist at other worlds to vary from those that exist at the actual world. This causes a problem for those who deny the existence of non-actual individuals. I focus on two prominent strategies for solving this problem, due respectively to Bernard Linsky and Edward Zalta (who identify the possible individuals with the actual individuals) and Alvin Plantinga (who identifies the possible individuals with the individual essences). I argue, contra various commentators, that both of these solutions are acceptable by the lights of those who deny the existence of mere possibilia.

There have been few attempts to draw a distinction between ficta (mythical and literary characters, and fictional creations in general) and unactualized possibilia (objects of unrealized assemblages, of false but coherent scientific theories, of unfulfilled plans) qua respective alleged referents of singular terms occurring in sentences apparently talking of them. Both have indeed been indistinctly rejected as belonging to the perverse domain of the non-existent. Those singular terms purporting to refer to them have consequently been considered as empty non-denoting terms or, at least sometimes in the case of fictional reference, as being used in contexts of pretended reference. This referential peculiarity seems to have been necessary in order to save the apparent truth of sentences belonging to fictional contexts. This policy, however, has the effect of blurring the ontological distinction between ficta and possibilia. On the one hand, ficta are a particular kind of abstract objects, namely constructed abstract objects. Moreover, they are essentially incomplete abstract entities, in that they are correlates of finite sets of properties. On the other hand, possibilia are concrete objects as well as realia, which are ultimately nothing but actualized possibilia. In fact, possible objects are objects that, even though they do not actually exist, might have existed, in the particular, Platonic-Kantian, sense of the firstorder concept of existence here involved, namely that of being effective, i.e. being involved in the causal order. Thus, being a possible unactualized object is tantamount to being possibly involved in the causal order. Besides, as an object existent in this sense may legitimately be qualified as complete, the incompleteness which pertains to possible objects may be said to be contingent, that is, to regard them only with respect to the worlds in which they do not exist. With ficta and possibilia two different notions of completeness are therefore brought into play, the former referring to a predicative, the latter to a propositional, concept of negation..

The problem with model-theoretic modal semantics is that it provides only the formal beginnings of an account of the semantics of modal languages. In the case of non-modal language, we bridge the gap between semantics and mere model theory, by claiming that a sentence is true just in case it is true in an intended model. Truth in a model is given by the model theory, and an intended model is a model which has as domain the actual objects of discourse, and which relates these objects in an appropriate manner. However, the same strategy applied to the modal case seems to require an intended modal model whose domain includes mere possibilia.Building on recent work by Christopher Menzel (Nous 1990), I give an account of model-theoretic semantics for modal languages which does not require mere possibilia or intensional entities of any kind. Menzel has offered a representational account of model-theoretic modal semantics that accords with actualist scruples, since it does not require possibilia. However, Menzel's view is in the company of other actualists who seek to eliminate possible worlds, but whose accounts tolerate other sorts of abstract, intensional entities, such as possible states of affairs. Menzel's account crucially depends on the existence of properties and relations in intension.

Are there, in addition to the various actual objects that make up the world, various possible objects? Are there merely possible people, for example, or merely possible electrons, or even merely possible kinds? We certainly talk as if there were such things. Given a particular sperm and egg, I may wonder whether that particular child which would result from their union would have blue eyes. But if the sperm and egg are never in fact brought together, then there is no actual object that my thought is about.1 Or again, in the semanti cs for modal logic we presuppose an ontology of possibilia twice over.2 For first, we coutenance various possible worlds, in addition to the actual world; and second, each of these worlds is taken to be endowed with its own domai n of objects. These will be the actual objects of the world in question, but they need not be actual simpliciter, i.e., actual objects of our world. W ha t a r e w e t o m a k e o f such discourse? There are four options: (i) the discourse is taken to be unintelligible; (ii) it is taken to be intelligible but nonfactual, i.e. as not in the business of stating facts; (iii) it is taken to be factual but reducible to discourse involving no reference to possibilia; (iv) it is taken to be both factual and irreducible.3 These options range from a fullblooded form of actualism at one extreme to a full-blooded form of possibilism at the other. The two intermediate positions are possibilist in that they accept the intelligibility of possibilist discourse but actualist in that they attempt to dispense with its prima facie commitment to possibilia. All four positions have found advocates in the literature. Quine, in his less irenic moments, favours option (i); Forbes ([85], p. 94) advocates option (ii), at least for certain parts of possibilist discourse; many philosophers, including Adams [74] and myself, opt for (iii); while Lewis [86] and Stalnaker [75] have endorsed versions of (iv), that differ in how full-blooded they take the possible objects to be. My focus in the present article is on the third option..