In On the Plurality of Worlds (Lewis 1986), David Lewis imposes a condition on realist theories of modality which he calls ‘plenitude’. Lewis apparently assigns this condition considerable importance, and uses it to motivate his Humean principle of recombination, but he never says exactly what plenitude amounts to. This chapter first sets aside some obvious ways of reconstructing the plenitude criterion which do not fit with the textual evidence. An objection to modal realism due to John Divers and Joseph Melia (...) (Divers and Melia 2002) is diagnosed as equivocating between an overly-demanding plenitude constraint and a weaker constraint which fails to establish their conclusion. An alternative deflationary interpretation of the plenitude condition has it following from an application of standard theoretical virtues to a modal realist’s total theory; Lewis’ correspondence provides new evidence in support of this interpretation. The deflationary plenitude criterion also has broader application, beyond Lewisian modal realism. (shrink)

An important motivation for believing in the modal realist’s ontology of other concrete possible worlds and their inhabitants is its theoretical utility, centrally the reduction of ordinary modal talk to counterpart theory as showcased by David Lewis’s 1968 translation scheme. In a recent paper Harold Noonan, following the lead of John Divers, argues that Lewis’s scheme is not strictly adequate by the modal realist’s own lights, and that nothing short of jettisoning de dicto contingency will help. In this paper, I (...) argue that this is a serious overreaction. First, I show that Noonan’s problem does not touch Lewis’s proposal, since his translation scheme is not even concerned with the relevant sentences. Thus, Noonan’s problem only points to a limit in scope. I then go on to propose a straightforward extension of the translation scheme that provides translations for the allegedly problematic sentences, but does so endangering neither adequacy nor de dicto contingency. (shrink)

What are the requirements on an adequate genuine modal realist analysis of modal discourse? One is material adequacy: the modal realist must provide for each candidate analysandum an analysans in the language of counterpart theory which by his lights has the same truth value as the candidate analysandum. Must the material biconditional joining these be necessarily true? This is the requirement of strict adequacy. It is not satisfied if Lewis’s 1968 scheme provides the analysis. John Divers puts forward a modification, (...) which identifies cases of ‘advanced modalizing’ in which the modal operator is semantically redundant. Even with this modification modal realist analyses of statements of modal discourse will be strictly inadequate. Strict adequacy can be achieved by extending the redundancy interpretation to all de dicto modal statements. The price is the denial of de dicto contingency. But perhaps material adequacy is enough. If the modal realist has a systematic means of replacing every sentence of quantified modal logic which he considers true by a sentence of counterpart theory that he considers true, perhaps he need do no more. Still, traditionally philosophical analysis aims at strict adequacy so it is as well to know that this is a test the modal realist analysis fails unless he abandons de dicto contingency. (shrink)

Necessitism is the controversial thesis that necessarily everything is necessarily something, namely that everything, everywhere, necessarily exists. What is controversial about necessitism is that, at its core, it claims that things could not have failed to exist, while we have a pre-theoretical intuition that not everything necessarily exists. Contingentism, in accordance with common sense, denies necessitism: it claims that some things could have failed to exist. Timothy Williamson is a necessitist and claims that David Lewis is a necessitist too. The (...) paper argues that, granted the assumptions that lead to interpret the Lewisian as a necessitist, she can preserve contingentist intuitions, by genuinely agreeing with the folk that existence is contingent. This is not just the uncontroversial claim that the Lewisian, as a result of the prevalence of restricted quantification in counterpart theoretic regimentations of natural language, can agree with the folk while disagreeing with them in the metaphysical room. Rather, this is the claim that it is in the metaphysical room that the Lewisian can endorse the intuitions lying behind contingentism. (shrink)

Presentism is typically characterised as the thesis that everything is present, and therefore there are no dinosaurs or Martian presidential inaugurations. Putting aside the vexed question of exactly what it is to be present in this context, this thesis seems quite straightforward. However, a number of authors—such as Merricks, Lombard, Meyer, Tallant and Sakon —have argued that Presentism so characterised is either trivially true or false even by Presentist lights. This is the so-called Triviality Argument against Presentism. In this paper (...) I show that three of the four premises of the Triviality Argument are plausibly false. I conclude that Presentists have nothing to fear from the Triviality Argument. (shrink)

I discuss a modification of Lewisian modal realism called 'inclusionism'. Inclusionism is the thesis that some worlds contain other worlds as proper parts. Inclusionism has some attractive consequences for theories of modality. Josh Parsons, however, has raised a problem for inclusionism: the problem of unmarried husbands. In this paper I reply to this problem. My strategy is twofold: first I claim, pace Parsons, that it is not clear why the inclusionist cannot avail herself of an obvious solution to the problem; (...) and second, I argue that even if there is no available solution, the same problem also afflicts Lewis' original theory. Therefore, even if the problem remains unsolved, we have not been given any reason to think that an inclusionist version of Lewisian realism is worse than the original. (shrink)

This paper investigates the form a modal realist analysis of possibility and necessity should take. It concludes that according to the best version of modal realism, the notion of a world plays no role in the analysis of modal claims. All contingent claims contain some de re element; the effect of modal operators on these elements is described by a counterpart theory which takes the same form whether the de re reference is to a world or to something else. This (...) fully general counterpart theory can validate orthodox modal logic, including the logic of 'actually'. (shrink)

My topic in this paper is the relationships of metaphysical priority which might hold between the different alethic modal statuses—necessity, contingency, possibility and impossibility. In particular, I am interested in exploring the view that the necessity of necessities is ungrounded while the contingency of contingencies is grounded—a scenario I call ‘necessity first’. I will explicate and scrutinize the contrast between necessity first and its ‘contingency first’ contrary, and then compare both views with ‘multimodal’ and ‘amodal’ alternatives, drawing on David Lewis’s (...) modal realism and Barbara Vetter’s potentialism as example cases. I will then defend the necessity-first point of view from a reversed version of Blackburn’s classic dilemma against theories of the source of necessity. (shrink)

Modal realists face a puzzle. For modal realism to be justified, modal realists need to be able to give a successful reduction of modality. A simple argument, however, appears to show that the reduction they propose fails. In order to defend the claim that modal realism is justified, modal realists therefore need to either show that this argument fails, or show that modal realists can give another reduction of modality that is successful. I argue that modal realists cannot do either (...) of these things and that, as a result, modal realism is unjustified and should be rejected. (shrink)