“There is no use in trying,” said Alice; “one can’t believe impossible things.” “I dare say you haven’t had much practice,” said the Queen. “When I was your age, I always did it for half an hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast”. Lewis Carroll, Through the Looking Glass. -/- It is a rather common view among philosophers that one cannot, properly speaking, be said to believe, conceive, imagine, hope for, or seek (...) what is impossible. -/- Some philosophers, for instance George Berkeley and the early Wittgenstein, thought that logically contradictory propositions lack cognitive meaning (informational content) and cannot, therefore, be thought or believed. Philosophers who do not go as far as Berkeley and Wittgenstein in denying that impossible propositions or states of affairs are thinkable, may still claim that it is impossible to rationally believe an impossible proposition. On a classical “Cartesian” view of belief, belief is a purely mental state of the agent holding true a proposition p that she “grasps” and is directly acquainted with. But if the agent is directly acquainted with an impossible proposition, then, presumably, she must know that it is impossible. But surely no rational agent can hold true a proposition that she knows is impossible. Hence, no rational agent can believe an impossible proposition. Thus it seems that on the Cartesian view of propositional attitudes as inner mental states in which proposition are immediately apprehended by the mind, it is impossible for a rational agent to believe, imagine or conceive an impossible proposition. -/- Ruth Barcan Marcus (1983) has suggested that a belief attribution is defeated once it is discovered that the proposition, or state of affairs that is believed is impossible. According to her intuition, just as knowledge implies truth, belief implies possibility. -/- It is commonplace that people claim to believe propositions that later turn out to be impossible. According to Barcan Marcus, the correct thing to say in such a situation is not: I once believed that A but I don’t believe it any longer since I have come to realize that it is impossible that A. What one should say is instead: It once appeared to me that I believed that A, but I did not, since it is impossible that A. Thus, Barcan Marcus defends what we might call Alice’s thesis: Necessarily, for any proposition p and any subject x, if x believes p, then p is possible. -/- Alice’s thesis that it is impossible to hold impossible beliefs, seems to come into conflict with our ordinary practices of attributing beliefs. Consider a mathematical example. Some mathematicians believe that CH (the continuum hypothesis) is true and others believe that it is false. But if CH is true, then it is necessarily true; and if it is false, then it is necessarily false. Regardless of whether CH is true or false, the conclusion seems to be that there are mathematicians who believe impossible propositions. -/- Examples of apparent beliefs in impossible propositions outside of mathematics are also easy to come by. Consider, for example, Kripke’s (1999) story of the Frenchman Pierre who without realizing it has two different names ‘London’ and ‘Londres’ for the same city, London. After having arrived in London, Pierre may assent to ‘Londres is beautiful and London is not beautiful’ without being in any way irrational. It seems reasonably to infer from this that Pierre believes that Londres is beautiful and London is not beautiful. But since ‘Londres’ and ‘London’ are rigid designators for the same city, it seems to follow from this that Pierre believes the inconsistent proposition that we may express as ‘London is both beautiful and not beautiful’. (shrink)

I happen to believe that though human experiences are to be characterized as pluralistic they are all rooted in the one reality. I would assume the thesis of pluralism but how could I maintain my belief in the realism? There are various discussions in favor of realism but they appear to stay within a particular paradigm so to be called “internal realism”. In this paper I would try to justify my belief in the reality by discussing a special use of (...) indexicals. I will argue for my indexical realism by advancing the thesis that indexicals can be used as an inter-agentic referential term. Three arguments for the thesis will be presented. The first argument derives from a revision of Kaplan-Kvart’s notion of exportation. Their notions of exportation of singular terms can be analyzed as intra-agentic exportation in the context of a single speaker and theirs may be revised so as to be an inter-agentic exportation in the context of two speakers who use the same indexicals. The second is an argument from the notion of causation which is specifically characterized in the context of inter-theoretic reference. I will argue that any two theories may each say “this” in order to refer what is beyond its own theory. Two theories address themselves to ‘this’ same thing though what ‘this’ represents in each theory turn out to be different objects all together. The third argument is an argument which is based on a possibility of natural reference. Reference is used to be taken mostly as a 3-place predicate: Abe refers an object oi with an expression ej. The traditional notion of reference is constructive and anthropocentric. But I would argue that natural reference is a reference that we humans come to recognize among denumerably many objects in natural states: at a moment mi in a natural state there is a referential relation among objects o1, o2, o3, . . , oj, o j+1, . . which interact to each other as agents of information processors. Natural reference is an original reference which is naturally given and to which humans are passive as we derivatively refer it by using ‘this’. (shrink)

Contingentism is the view that it is possible for there to be contingent existents. Timothy Williamson has argued that contingentists cannot provide a satisfactory interpretation of the possible-world semantics for modal logic. This paper aims to provide such an interpretation on behalf of contingentists.

The standard interpretation of "Theaetetus" 152-160 has Plato attribute to Protagoras a relativistic theory of truth and existence. It is argued here that in fact the individuals of Protagorean worlds are inter-Personal. (thus the Protagorean theory has public objects, but private truth). Also, a new interpretation is offered of Plato's use of heraclitean flux to model relativism. The philosophical and semantic consequences of the interpretation are explored.

A detailed interpretation is provided of the ‘Gray's Elegy’ passage in Russell's ‘On Denoting’. The passage is suffciently obscure that its principal lessons have been independently rediscovered. Russell attempts to demonstrate that the thesis that definite descriptions are singular terms is untenable. The thesis demands a distinction be drawn between content and designation, but the attempt to form a proposition directly about the content (as by using an appropriate form of quotation) inevitably results in a proposition about the thing designated (...) instead of the content expressed. In light of this collapse, argues Russell, the thesis that definite descriptions are singular terms must accept that all propositions about a description's content represent it by means of a higher-level descriptive content, so that knowledge of a description's content is always ‘by description’, not ‘by acquaintance’. This, according to Russell, renders our cognitive grip on definite descriptions inexplicable. Separate responses on behalf of Fregeans and Millians are offered. (shrink)

Neste artigo, tomei certas idéias da semântica de Montague como meu ponto de partida e distingui claramente semântica de epistemologia. O significado de uma sentença é considerado como suas condições de verdade as quais são assumidas como sendo estabelecidas por dois componentes: a estrutura sintática e os referentes de termos sem estrutura. Nesse panorama teórico, tento apresentar uma explicação para o significado dos termos de espécies naturais. Minha tese é que o significado de um termo de espécie natural é sua (...) referência, i. e., a espécie natural à qual o termo refere-se. (shrink)

The broad aim of this thesis is to explore fruitful connections between ideology theory and the philosophy of possible worlds. Ideologies are full of modal concepts, such as possibility, potential, necessity, essence, contingency and accident. Typically, PWs are articulated for the analysis and illumination of modal concepts. That naturally suggests a method for theorising ideological modality, utilising PW theory. The specific conclusions of the thesis proffer a number of original contributions to knowledge: 1) PWs should only be used for explication (...) and not as evidence or criteria of assessment in ideology theory. The estimation of utopian possibilities, human essences and freedoms must be determined by extrinsic criteria. PWs can serve only as a window or means of expression but not as a set of evaluative premises. 2) For this purpose, a modified version of Lewisian genuine realism, with its device of counterpart theory, is the best approach; the alternative theories risk constricting possibilities or smuggling in assumptions that ought to be objects of analysis in ideology theory. This is instructive, since ideology theorists are prone to pick and choose favoured aspects of modal philosophy without further argument. 3) Conclusions and suggest the adoption of GR or fictionalist GR. Overall, the actualist options are less adequate. Fictionalism, by contrast, is a worthwhile contender, but it too presents comparative weaknesses which reinforce GR’s standing as a potent challenger to the modal metaphysician. Therefore, this thesis presents additional reasons to think GR true. The conclusions are not knockdown, and I draw out incentives and consequences for adopting alternative stances. The various chapters also provide specific details for comprehending and debating ideological modals. (shrink)

Russell alleged that the version of the cosmological argument he debated with Copleston involved type confusions, but the definitions of plural descriptive functions and the ancestral in Principia Mathematica can be used to reformulate the argument in a type-safe way via a notion of causally self-sufficient classes. Although the argument depends on the assumption that the class of contingent things is not causally self-sufficient, if that assumption is weakened to say only that it may not be so, then a new (...) modalized version emerges which has similarities with recent ontological arguments but weaker and more intuitive assumptions. (Familiarity with Principia notation and conventions is presupposed throughout.). (shrink)

Evidence is drawn together to connect sources of inconsistency that Frege discerned in his foundations for arithmetic with the origins of the paradox derived by Russell in "Basic Laws" I and then with antinomies, paradoxes, contradictions, riddles associated with modal and intensional logics. Examined are: Frege's efforts to grasp logical objects; the philosophical arguments that compelled Russell to adopt a description theory of names and a eliminative theory of descriptions; the resurfacing of issues surrounding reference, descriptions, identity, substitutivity, paradox in (...) the debates concerning modal and intensional logics; the development of the New Theory of Reference. I consider this to be the philosophical ground upon which the debates regarding that theory should take place. (shrink)

Necessitists hold that, necessarily, everything is such that, necessarily, something is identical to it. Timothy Williamson has posed a number of challenges to contingentism, the negation of necessitism. One such challenge is an argument that necessitists can more wholeheartedly embrace possible worlds semantics than can contingentists. If this charge is correct, then necessitists, but not contingentists, can unproblematically exploit the technical successes of possible worlds semantics. I will argue, however, that the charge is incorrect: contingentists can embrace possible worlds semantics (...) as wholeheartedly as necessitists. Williamson offers a criterion for a class of models of quantified modal logic to be intended, and argues on its basis that contingentists must deny that there is an intended class of models. I argue that Williamson’s criterion is objectionable, supply an alternative that does not support Williamson’s argument, and adapt Williamson’s construction of an intended model structure to the needs of contingentist metaphysics. (shrink)

Le nominalisme est « le refus d'admettre toute entité autre qu'indivi-duelle ». II doit, pour justifier la simplicité de son ontologie, proposer une théorie de laconnaissance et une théorie sémantique qui ne présupposent ni l'une ni l'autre l'existence réelle des univer-saux. Certaines des voies qui s'ouvrent à cette entreprise délicate ont été systématiquement explorées vers la fin du Moyen Age et il y a tout à parier que, malgré les ruptures épistémologiques, les révolutions scientifiques et autres changements d'epistémè, les nominalistes (...) contemporains pourraient encore profiter de quelque façon de l'immense travail théorique accompli par leurs prédécesseurs médiévaux. C'est dans cet esprit que je voudrais procéder à une reconstruction sommaire de la théorie sémantique avancée au début du quatorzième siècle par le Fran-ciscain Guillaume d'Occam. Je ne m'engagerai pas dans une comparaison détaillée entre Occam et les auteurs contemporains, mais j'essaierai de présenter sans en trahir l'esprit la sémantique occa-miste de manière à en faire apparaître la pertinence pour les débats actuels. II serait possible, me semble-t-il, d'aller encore plus loin dans cette voie en mettant à profit les techniques formelles récentes pour axiomatiser la théorie d'Occam. Pour l'instant cependant, je me limiterai à une présentation plutôt informelle. (shrink)

This essay examines some of the arguments in David Deutsch's book The Fabric of Reality , chief among them its case for the so-called many-universe interpretation of quantum mechanics (QM), presented as the only physically and logically consistent solution to the QM paradoxes of wave/particle dualism, remote simultaneous interaction, the observer-induced 'collapse of the wave-packet', etc. The hypothesis assumes that all possible outcomes are realized in every such momentary 'collapse', since the observer splits off into so many parallel, coexisting, but (...) epistemically non-interaccessible 'worlds' whose subsequent branchings constitute the lifeline-or experiential world-series- for each of those proliferating centres of consciousness. Although Deutsch concedes that his 'multiverse' theory is counter-intuitive, he none the less takes it to be borne out beyond question by the sheer observational/predictive success of QM and the conceptual dilemmas that supposedly arise with alternative (single-universe) accounts. Moreover, he claims the theory resolves a range of longstanding philosophical problems, notably those of mind/body dualism, the various traditional paradoxes of time, and the freewill/determinism issue. The essay suggests on the contrary, that Deutsch unwittingly transposes into the framework of presentday quantum debate speculative themes from the history of rationalist metaphysics, often with bizarre or philosophically dubious results, and that he rules out at least one promising rival account, namely Bohm's 'hidden variables' theory. It goes on to consider reasons for resistance to that theory among proponents of the 'orthodox' (Copenhagen) doctrine, and for the strong anti-realist, at times even irrationalist bias that has characterized much of this discussion since Bohr's debates with Einstein about quantum non-locality, observer-intervention, and the limits of precise measurement. Finally, the contrast is pointed out between Deutsch's ontologically extravagant use of the many-worlds hypothesis (akin to certain ideas advanced by speculative metaphysicians from Leibniz down) and those realist modes of counterfactual reasoning- e.g. in Kripke and the early Putnam- which deploy similar arguments to very different causal-explanatory ends. (shrink)

Donnellan famously argued that while one can fix the reference of a name with a definite description, one cannot thereby have a de re belief about the named object. All that is generated is meta-linguistic knowledge that the sentence “If there is a unique F, then N is F” is true. Donnellan’s argument and the sceptical position are extremely influential. This article aims to show that Donnellan’s argument is unsound, and that the Millian who embraces Donnellan’s scepticism that the reference-fixer (...) cannot secure the relevant de re belief faces a serious problem: Millianism about names plus scepticism about the reference-fixer’s de re belief conflicts with what seems to be an analytical thesis about the relationship between semantic content and understanding. The upshot is that the Millian has good reason to seek an alternative to scepticism. (shrink)

The Hooded Man Paradox of Eubulides concerns the apparent failure of the substitutivity of identicals in epistemic (and other intentional) contexts. This paper formulates a number of different versions of the paradox and shows how these may be solved using semantics for quantified epistemic logic. In particular, two semantics are given which invalidate substitution, even when rigid designators are involved.

I argue that metaphysicians of mind have not done justice to the notion of accessibility between possible worlds. Once accessibility is given its due, physicalism must be reformulated and conceivability arguments must be reevaluated. To reach these conclusions, I explore a novel way of assessing the zombie conceivability argument. I accept that zombies are possible and ask whether that possibility is accessible from our world in the sense of ‘accessible’ used in possible world semantics. It turns out that the question (...) whether zombie worlds are accessible from our world is equivalent to the question whether physicalism is true at our world. By assuming that zombie worlds are accessible from our world, proponents of the zombie conceivability argument beg the question against physicalism. In other words, it is a mistake to assume that the metaphysical possibility of zombies entails that physicalism is false at our world. I will then consider what happens if a proponent of the zombie conceivability argument should insist that zombie worlds are accessible from our world. I will argue that the same ingredients used in the zombie conceivability argument—whatever exactly they might be—can be used to construct an argument to the opposite conclusion. At that point, we reach a stalemate between physicalism and property dualism: while the possibility of zombies entails property dualism, the possibility of other creatures entails physicalism. Since these two possibilities are mutually inconsistent, either one of them is not genuine or one of them is inaccessible from the actual world. To resolve this stalemate, we need more than traditional conceivability arguments. (shrink)

Referential opacity is the failure of substitutivity of identity (SI, for short) and in Quine’s view of existential generalization (EG, for short) as well. Quine thinks that its “solution” in epistemic and doxastic contexts, which relies on the notion of exportation, leads to undesirable results. But epistemic logicians such as Jaakko Hintikka and Wolfgang Lenzen provide another solution based on a different diagnosis: opacity is not, as in Quine’s view, due to the absence of reference, it is rather due to (...) the plurality of references; therefore, one must stabilize the reference to restore SI and EG. However, Hintikka’s semantics remains classical in its treatment of existence, which makes EG non-applicable to possible objects, while in Lenzen’s system, EG is applicable by means of a particular quantifier. But this requires adding the predicate of existence to account for real objects. In this paper, I will show the advantages and disadvantages of both solutions and will end by providing an alternative approach to the problem of non-existent objects, which stays into the frame of possible worlds semantics, but introduces some more restrictions, eliminates the problematic predicate of existence, and applies a neutral quantifier to possible non-existent objects. (shrink)

This chapter contains sections titled: Introduction Modal propositional Logics (MPLs) Modal Quantificational Logics(QMLs).