This is an introduction to the topic of modality in philosophy. Theories of modality seek to explain possibility and necessity in the various ways they come up in our ordinary understanding of the world and in our systematic theorising. Topics covered include distinguishing types of necessity and possibility; possible worlds and their use; de re possibility and necessity; and how we discover modal truths.

[full article, abstract in English; only abstract in Lithuanian] The paper deals with the problem of the “two Barbaras” in the Aristotelian modal syllogistic. The problem consists in Aristotle’s differing views on two at a first sight similar in nature syllogisms of mixed assertoric and necessary premises: Barbara LXL and Barbara XLL. The fact that Aristotle believed the first syllogism to be valid and the second one – not, has been received either 1) negatively, because both Barbaras have been held (...) to be invalid, or 2) negatively, because both Barbaras have been held to be valid, or 3) positively, by giving a reason why the two Barbaras differ. We commit ourselves to the position by proving that modal propositions for Aristotle have their modalities de dicto and that Aristotelian modal operators act according to their own separate rules where only the type of the modality of a major premise is relevant for the modal status of the conclusion. (shrink)

One of the open problems in the philosophy of information is whether there is an information logic (IL), different from epistemic (EL) and doxastic logic (DL), which formalises the relation “a is informed that p” (Iap) satisfactorily. In this paper, the problem is solved by arguing that the axiom schemata of the normal modal logic (NML) KTB (also known as B or Br or Brouwer’s system) are well suited to formalise the relation of “being informed”. After having shown that IL (...) can be constructed as an informational reading of KTB, four consequences of a KTB-based IL are explored: information overload; the veridicality thesis (Iap → p); the relation between IL and EL; and the Kp → Bp principle or entailment property, according to which knowledge implies belief. Although these issues are discussed later in the article, they are the motivations behind the development of IL. (shrink)

The present PhD dissertation aims to examine the relation between modality and change in Aristotle’s metaphysics. -/- On the one hand, Aristotle supports his modal realism (i.e., worldly objects have modal properties - potentialities and essences - that ground the ascriptions of possibility and necessity) by arguing that the rejection of modal realism makes change inexplicable, or, worse, banishes it from the realm of reality. On the other hand, the Stagirite analyses processes by means of modal notions (‘change is the (...) actuality of what is virtual insofar as it is virtual’). In other words: to grasp what change is, one has to resort to the modal idiom of potentialities, while the fact that there is change is indicative of the fact that nature is full of modal properties. -/- Aristotle’s modal and kinetic realism finds a negative in the figure of the Megaric Diodorus Kronus. The polemical situation of Greek philosophy has indeed the dialectical advantage of not opposing the Aristotelian position to a sui generis straw man. Both in its reduction of modal judgements to temporal quantifications and in its dissolution of the reality of the state-of-being-in-motion in favour of a cinematographic view of processes, the philosophical figure of reductionist antirealism embodied by Diodorus constitutes an alternative that takes the opposite view of Aristotle’s realism. -/- The present study is structured as a discussion between these two positions. In the face of Diodorus’ antirealist challenges, Aristotle articulates modal and kinetic considerations: the answers he gives to Diodorus’ puzzles thus provide valuable insight into his metaphysics. Moreover, the examination of Aristotle’s and Diodorus’ metaphysics, because of their insight and originality, will not fail to interest the philosopher concerned with the metaphysical foundations of modern physics, insofar as the entanglement between modalities and processes is nowadays at the core of mechanics (phase spaces, path integrals, etc.). (shrink)

One debate that metaphysicians of race have been consumed with since the 1990s is what we can call the US race debate, which is the debate about what the nature and reality of race is according to the dominant ways that ‘race’ and race terms are used to classify people in contemporary American English. In 2014, I contributed a defence of biological racial realism in the US race debate that utilized new results about human genetic clustering from population genetics. In (...) this paper, I will show that all US race theories have been wrong, including my own. This is because, as I will argue, the correct US race theory has a radically pluralist form. This is an instance of a metametaphysical position that I call radical racial pluralism. After defending radical racial pluralism in the US race debate, I explore valuable implications of the view for philosophers of race. (shrink)

This paper will present two contributions to teaching introductory logic. The first contribution is an alternative tree proof method that differs from the traditional one-sided tree method. The second contribution combines this tree system with an index system to produce a user-friendly tree method for sentential modal logic.

It is widely alleged that metaphysical possibility is “absolute” possibility Conceivability and possibility, Clarendon, Oxford, 2002, p 16; Stalnaker, in: Stalnaker Ways a world might be: metaphysical and anti-metaphysical essays, Oxford University Press, Oxford, 2003, pp 201–215; Williamson in Can J Philos 46:453–492, 2016). Kripke calls metaphysical necessity “necessity in the highest degree”. Van Inwagen claims that if P is metaphysically possible, then it is possible “tout court. Possible simpliciter. Possible period…. possib without qualification.” And Stalnaker writes, “we can agree (...) with Frank Jackson, David Chalmers, Saul Kripke, David Lewis, and most others who allow themselves to talk about possible worlds at all, that metaphysical necessity is necessity in the widest sense.” What exactly does the thesis that metaphysical possibility is absolute amount to? Is it true? In this article, I argue that, assuming that the thesis is not merely terminological, and lacking in any metaphysical interest, it is an article of faith. I conclude with the suggestion that metaphysical possibility may lack the metaphysical significance that is widely attributed to it. (shrink)

In the early 2000s, Esteban Burchard and his colleagues defended a controversial route to the view that there’s a racial classification of people that’s useful in medicine. The route, which I call ‘Burchard’s route,’ is arguing that there’s a racial classification of people that’s useful in medicine because, roughly, there’s a racial classification with medically relevant genetic differentiation :1170–1175, 2003). While almost all scholars engaged in this debate agree that there’s a racial classification of people that’s useful in medicine in (...) some way, there’s tremendous controversy over whether any racial scheme is useful in medicine because there are medically relevant genetic differences among those races : 564–565, 2016). The goal of this paper will be to show that Burchard’s route is basically correct. However, I will use a slightly different argument than Burchard et al.’s in order to provide a firmer foundation for the thesis, both metaphysically and genetically. I begin by reviewing Burchard’s route and its critics. Second, I present an original argument for establishing Burchard et al.’s conclusion using a Burchard-like route. I call it ‘Spencer’s route’. I reply to major objections along the way, and I end with a summary. (shrink)

Epistemic logic begins with the recognition that our everyday talk about knowing and believing has some systematic features that we can track and re‡ect upon. Epistemic logicians have studied and extended these glints of systematic structure in fascinating and important ways since the early 1960s. However, for one reason or another, mainstream epistemologists have shown little interest. It is striking to contrast the marginal role of epistemic logic in contemporary epistemology with the centrality of modal logic for metaphysicians. This article (...) is intended to help in correcting this oversight by presenting some important developments in epistemic logic and suggesting ways to understand their applicability to traditional epistemological problems. Obviously, by itself, tweaking the formal apparatus of epistemic logic does not solve traditional epistemological problems. Epistemic logic can help us to navigate through problems in a systematic fashion by unpacking the logic of the problematic concepts, it can also lead us to recognize problems that we had not anticipated. This is basically analogous to the role that modal logic has played in contemporary metaphysics. (shrink)

Let us call a property that is essentially dispositional a potency.1 David Armstrong thinks that potencies do not exist. All sparse properties are essentially categorical, where sparse properties are the explanatory properties of the type science seeks to discover. An alternative view, but not the only one, is that all sparse properties are potencies or supervene upon them. In this paper I shall consider the differences between these views, in particular the objections Armstrong raises against potencies.

This dissertation is an investigation into the relation between mind and language from different perspectives, split up into three interrelated but still, for the most part, self-standing parts. Parts I and II are concerned with the question how thought is affected by language while Part III investigates the scope covered by mind and language respectively. Part I provides a reconstruction of Ludwig Wittgenstein’s famous Private Language Argument in order to apply the rationale behind this line of argument to the relation (...) between mind and language. This argumentative strategy yields the conclusion that reasoning – an important type of thought – is constitutively dependent on language possession and is therefore not available to non-linguistic creatures. This result is achieved by considering the preconditions for reasoning – given that it is a rule-governed activity – and eliminating competitors to language for providing reasoners with what it takes to reason. Part II provides a critical outlook on the wide and highly heterogeneous field of linguistic relativity theories. It is argued that no kind of linguistic relativity whatsoever follows from the conclusion of Part I – i.e., the claim that reasoning is constitutively dependent on having a language. While Part II does not provide a conclusive argument against the linguistic relativity hypothesis, it is argued that endorsement of linguistic relativity theories often rests on a mistaken assumption to the effect that language and culture are interwoven in a way which makes it impossible to separate culture and language, as well as their respective studies. This assumption is undermined by providing examples of languages which clearly predate their culture or do not even have a culture at all. So, the assumption that language and culture are inextricably intertwined is refuted by way of counterexample. Part III provides an in-depth examination of the Principle of Expressibility – prominently endorsed and formulated by John Searle – which claims that whatever can be thought can also be said. The domains of what can be thought and of what can be said are considered in set theoretic terms in order to determine whether one is contained in the other, so that everything we can think can also be adequately communicated. After thorough study of interpretative issues regarding the Principle of Expressibility and consideration of the most pressing potential counterexamples to the principle, we can conclude that we have good reason to believe in the truth of the Principle of Expressibility. In conclusion, the achieved results are related back to prominent positions in the discussion about thought and language which already make their appearance in the very beginning of this investigation. The final chapter of this dissertation reminds us that eminent figures in philosophy have often taken a wrongheaded perspective on the relation between language and thought, so that language has frequently appeared to be an impediment to thought. We can, however, confidently conclude that language, on the contrary, is by far our most apt means for thought and that reasoning would not even be possible without the resources language provides. (shrink)

The logic of ‘being informed’ gives a formal analysis of a cognitive state that does not coincide with either belief, or knowledge. To Floridi, who first proposed the formal analysis, the latter is supported by the fact that unlike knowledge or belief, being informed is a factive, but not a reflective state. This paper takes a closer look at the formal analysis itself, provides a pure and an applied semantics for the logic of being informed, and tries to find out (...) to what extent the formal analysis can contribute to an information-based epistemology. (shrink)

Kniha, jako je tato, nemůže být tak docela dílem jediného člověka. Dovést ji do podoby koherentního celku bych nedokázal bez pomoci svých kolegů, kteří po mně text četli a upozornili mě na spoustu chyb a nedůsledností, které se v něm vyskytovaly. Můj dík v tomto směru patří zejména Vojtěchu Kolmanovi, Liboru Běhounkovi a Martě Bílkové. Za připomínky k různým částem rukopisu jsem vděčen i Pavlu Maternovi, Milanu Matouškovi, Prokopu Sousedíkovi, Vladimíru Svobodovi, Petru Hájkovi a Grahamu Priestovi. Kniha vznikla v rámci (...) projektu podpořeného grantem AV ČR číslo A0009001/00. (shrink)

This paper examines the paradox of revisability. This paradox was proposed by Jerrold Katz as a problem for Quinean naturalised epistemology. Katz employs diagonalisation to demonstrate what he takes to be an inconsistency in the constitutive principles of Quine's epistemology. Specifically, the problem seems to rest with the principle of universal revisability which states that no statement is immune to revision. In this paper it is argued that although there is something odd about employing universal revisability to revise itself, there (...) is nothing paradoxical about this. At least, there is no paradox along the lines suggested by Katz. (shrink)

This paper sets out a semantics for C.I. Lewis's logic S2 based on the ontology of his 1923 paper ‘Facts, Systems, and the Unity of the World’. In that article, worlds are taken to be maximal consistent systems. A system, moreover, is a collection of facts that is closed under logical entailment and conjunction. In this paper, instead of defining systems in terms of logical entailment, I use certain ideas in Lewis's epistemology and philosophy of logic to define a class (...) of models in which systems are taken to be primitive elements but bear certain relations to one another. I prove soundness and completeness for S2 over this class of models and argue that this semantics makes sense of at least a substantial fragment of Lewis's logical theory. (shrink)

Metaphysics and ethics are two distinct fields in academic philosophy. The object of metaphysics is what is, while the object of ethics is what ought to be. Necessitarianism is a modal doctrine that appears to obliterate this neat distinction. For it is commonly assumed that ought (at least under normal circumstances) implies can. But if necessitarianism is true then I can only do what I actually do. Hence what I ought to do becomes limited to what I in fact do. (...) This is one widespread way of construing the danger that necessitarianism poses for ethics. There is, however, another way in which this collapse of what is with what ought to be can be construed. One could think of what is as already being what ought to be, of the two being one. On this picture, everything that is, is already valuable. In this thesis I explore the theory that being is intrinsically valuable. I do so by investigating the philosophy of perfection present in the works of the early modern rationalist Spinoza. For in his philosophy of perfection, I argue, we find being and value to be perfectly aligned. Hence, my reading challenges a widespread interpretation, according to which (ontological) perfection is divested of normativity in Spinozism. The position that all being is intrinsically valuable since it is perfect may be thought to be incompatible with human perfectionism. For what room can there be for human progress toward an ideal of perfection if all that exists, is necessarily perfect? The goal of the thesis is to respond to this question by providing a systematic interpretation of the metaphysics of human perfectibility in Spinoza’s philosophy. In order to achieve this goal, I undertake two tasks. First, I examine Spinoza’s multi-faceted philosophy of perfection. I distinguish between ontological and teleological perfection. Moreover, I argue that since Spinoza maintains that everything is perfect to the extent that it is, perfection shoulders the role of a transcendental within his system. In order to highlight the normative significance of transcendental perfection, I compare Spinoza’s thought with the transcendental theory of the good in Thomas Aquinas. In addition, I distinguish between ontological and speculative perfection. Speculative perfection is conscious awareness of ontological perfection. Second, I show how infinity plays an essential role in Spinoza’s ethics by indicating how we, by availing ourselves of this notion, are able to acquire a perspective on reality from which its ontological perfection may be discovered. On this basis, I am able to demonstrate the (relatively understudied) ethical and soteriological importance of Spinoza’s conception of infinity. I argue that it is because (a) Spinoza’s ideal of human perfection is speculative, and because (b) one will be able to establish the (ontological) perfection of things by deducing it from the divine essence only when one considers this essence absolutely infinite, that (c) the absolute infinity of the divine essence plays a significant role in Spinoza’s account of human perfection as consisting in conscious awareness of the value of all being. (shrink)