It used to be thought that rational coherence and metaphysical possibility went hand in hand. Kripke and Putnam put a spanner in the works by proposing examples of propositions which seem to violate this principle. I will propose a nuanced form of modal rationalism consistent with the Kripke/putnam cases. The rough idea is that rational coherence entails possibility when you grasp the essential nature of what you’re conceiving of.

Modal rationalism includes the thesis that ideal primary positive conceivability entails primary possibility. Modal monism is the thesis that the space of logically possible worlds is coextensive with the space of metaphysically possible worlds. In this paper I explore the relation between the two theses. My aim is to show that the former thesis implies the latter thesis, and that problems with the latter make the former implausible as a complete picture of the epistemology of modality. My (...) argument explores the relation between logical modality and metaphysical modality. (shrink)

I present a case for a rapprochement between aspects of rationalism and scientific realism, by way of a general framework employing modal epistemology and elements of 2-dimensional semantics (2DS). My overall argument strategy is meta-inductive: The bulk of this paper establishes a “base case,” i.e., a concretely constructive example by which I demonstrate this linkage. The base case or constructive example acts as the exemplar for generating, in a constructively ‘bottom-up’ fashion, a more generally rigorous case for (...) class='Hi'>rationalism-realism qua modal epistemology. The exemple I choose in D. Chalmers’ (2002) modal rationalism and R. Giere’s (1985, 1988) constructive realism. I show by way of a thorough analysis how Giere’s claims concerning modal scope are characterized as instances of Chalmers’ modal rationalism, both weak and strong. In essence, as I demonstrate via Chalmers’ notions, ceteris paribus the constructive realist ultimately opts for a comparatively wider gate, characterized by modal reasoning, to lead from the rooms of conceivability qua thought experiments and models, to the pastures of metaphysical possibility. Chalmers likewise tries to erect such a wider gate, in his general conceivability-possibility theses. Anti-realists, on the other hand, see a narrower passage and my contention herein is that they suffer from modal myopia, which hopefully the ‘corrective vision’ of Chalmers’ modal rationalism can restore. In the introduction and concluding sections I sketch out suggestions of constructing ‘inductive steps’ from my base case, to generate more extensively general claims regarding realism qua rationalism. -/- . (shrink)

The objection from the insolvability of principle-based modal disagreements appears to support the claim that there are no objective modal facts, or at the very least modal facts cannot be accounted for by modal rationalist theories. An idea that resurfaced fairly recently in the literature is that the use of ordinary empirical statements presupposes some prior grasp of modal notions. If this is correct, then the idea that we may have a total agreement concerning empirical (...) facts and disagree on modal facts, which is the starting point of the objection from the insolvability of modal disagreement, is undercut. This paper examines the no-separation thesis and shows that some of the arguments against the classical (empiricist) distinction between empirical and modal statements fail to be conclusive if they are taken to defend a strong notion of metaphysical possibility. The no-separation thesis appears to work only in theoretical frameworks where metaphysical modalities are considered (broadly) conceptual. For these reasons, the no-separation thesis cannot save modal rationalism from the insolvability of modal disagreement. (shrink)

According to the scrutability argument against physicalism, an a priori gap between the physical and conscious experience entails a lack of necessitation and the falsity of physicalism. This paper investigates the crucial premise of the scrutability argument: the inference from an a priori gap to a lack of necessitation. This premise gets its support from modal rationalism, according to which there are important, potentially constitutive, connections between a priori justification and metaphysical modality. I argue against the strong form (...) of modal rationalism that underwrites the scrutability argument and suggest a more moderate rationalist view. I offer a novel demonstrative reply to the scrutability argument, according to which demonstratives play a vital role in the generation of meaning for our representations of conscious experience. This connection between conscious experience and demonstratives, rather than a metaphysical gap generated by the truth of dualism, is the source of the epistemic gap between consciousness and the physical. (shrink)

In this chapter, it is suggested that our epistemic access to metaphysical modality generally involves rationalist, a priori elements. However, these a priori elements are much more subtle than ‘traditional’ modal rationalism assumes. In fact, some might even question the ‘apriority’ of these elements, but I should stress that I consider a priori and a posteriori elements especially in our modal inquiry to be so deeply intertwined that it is not easy to tell them apart. Supposed metaphysically (...) necessary identity statements involving natural kind terms are a good example: the fact that empirical input is crucial in establishing their necessity has clouded the role and content of the a priori input, as I have previously argued. For instance, the supposed metaphysically necessary identity statement involving water and its microstructure can only be established with the help of a controversial a priori principle concerning the determination of chemical properties by microstructure. The Kripke-Putnam framework of modal epistemology fails precisely because it is unclear whether the required a priori element is present. My positive proposal builds on E. J. Lowe’s work. Lowe holds that our knowledge of metaphysical modality is based on our knowledge of essence. Lowe’s account strives to offer a uniform picture of modal epistemology: essence is the basis of all our modal knowledge. This is the basis of Lowe’s modal rationalism. I believe that Lowe’s proposal is on the right lines in the case of abstract objects, but I doubt that it can be successfully applied to the case of natural kinds. Accordingly, the case of natural kinds will be my main focus and I will suggest that modal rationalism, at least as it is traditionally understood, falls short of explaining modal knowledge concerning natural kinds. Yet, I think that Lowe has identified something of crucial importance for modal epistemology, namely the essentialist, a priori elements present in our modal inquiry. The upshot is that rather than moving all the way from modal rationalism to modal empiricism, a type of hybrid approach, ‘empirically-informed modal rationalism ’, can be developed. (shrink)

Hossack (2007) defends what he calls the rationalist thesis: the thesis that necessity reduces to (or at least always coincides with) a priori knowledge. In this paper I discuss some features of Hossack’s rationalist account of necessity. In the first half, I attempt to fill in a missing link in the rationalist thesis, connecting the notions of primitiveness of facts and a priori modes of presentation. In the second half, I complain that the strategy of dissolving counterexamples is not enough, (...) and that a general principle connecting necessity and a prioricity is needed. I suggest further kinds of counterexamples that might arise, but rather than demand a response to each counterexample, I suggest that they highlight the need for a general argument for the rationalist thesis. (shrink)

The lesson is familiar. Kripke’s arguments in favor of a posteriori necessary truths annul the idea that conceivability is a guide to metaphysical possibility because determining that which is a priori is a separate issue from determining that which is necessary. Modal rationalists do not completely agree with this conclusion. Following recent work on two-dimensional semantics, David Chalmers suggests that two distinct semantic values can be assigned to a statement, depending on whether we consider possible worlds as counterfactual or (...) counteractual. The idea is that counterfactual possibilities yield familiar Kripkean intuitions, but that counteractuals fulfill the desired link between a priori conceivability and metaphysical possibility. In this paper, I discuss a problem for modalrationalism that arises through the use of material conditionals, or conditionals in the indicative mood. I then turn to Chalmers’ response, and suggest reasons why it is inadequate. I turn to another response from Chalmers, and suggest that, whilst it solves the fi rst issue, it is incapable of grounding modal rationalism. In conclusion I will suggest a way in which a tempered version of modal rationalism can be salvaged. (shrink)

Type-B materialists (to use David Chalmers's jargon) claim that though zombies are conceivable, they are not metaphysically possible. This article calls this position regarding the relation between metaphysical and epistemic modality “modal autonomism,” as opposed to the “modal rationalism” endorsed by David Chalmers and Frank Jackson, who insist on a deep link between the two forms of modality. This article argues that the defense of modal rationalism presented in Chalmers and Jackson (2001) begs the question (...) against the type-B materialist/modal autonomist. The argument proceeds as follows. Modal rationalists claim that for all nonphenomenal macro properties, the appropriate supervenience conditional is both necessary and a priori. Hence, type-B materialists must engage in special pleading when they claim that the relevant supervenience conditional for phenomenal properties, expressing the supervenience of the phenomenal on the physical, is necessary but not a priori. However, what Chalmers and Jackson demonstrate, if anything, is that the conditional that includes all the microphysical plus the phenomenal in the antecedent, and nonphenomenal macro facts (such as facts about water and other natural kinds, among other things) in the consequent, is a priori. The question arises why, since facts about water and the like do not metaphysically supervene on the phenomenal facts, is it appropriate to include the phenomenal facts in the antecedent of the relevant supervenience conditional. This article argues for the following claims: First, that it's crucial to the general semantic framework Chalmers and Jackson defend that they do include the phenomenal facts in the supervenience conditional; without them, the conditional would not be a priori. Second, that the only way to argue from the a priori character of these conditionals to the applicability of modal rationalism to the nonphenomenal cases is to rely either on modal rationalism itself or on the denial of type-B materialism. Obviously, in the context of this argument, either way would beg the question. (shrink)

Thought: A Journal of Philosophy, EarlyView.

In this paper, I discuss the main characteristics of the epistemology of modal rationalism by proceeding from the critical investigation of Peacocke’s theory of modality. I build on arguments by Crispin Wright and Sonia Roca-Royes, which are generalised and supplemented by further analysis, in order to show that principle-based accounts have little prospects of succeeding in their task of providing an integrated account of the metaphysics and the epistemology of modality. I argue that it is unlikely that we (...) will able to develop an exhaustive and accurate principle-based account that discriminates objectively between correct and deviant modal knowledge. Even if such an account can be formulated, a non-circular way of justifying its necessity also seems to be out of our reach. (shrink)

Modal rationalism is the claim that for any proposition p, if it is ideally conceivable that p, then there is a metaphysically possible world, W, in which p is true. If true, modal rationalism must itself be an a priori truth. Moreover, modal rationalism is true just if there are no strong a posteriori necessities. But are there any strong necessities? In this paper, I set out a transcendental argument to show that there cannot (...) be any, because they are not genuinely conceivable. I argue that if it were ideally conceivable that there are strong necessities, then it would be impossible for us to have any modal knowledge of the world. Given that we do have some modal knowledge of the world, it follows that strong necessities are not ideally conceivable and therefore that modal rationalism itself is an a priori truth. (shrink)

The paper begins with a clarification of the notions of intuition (and, in particular, modal intuition), modal error, conceivability, metaphysical possibility, and epistemic possibility. It is argued that two-dimensionalism is the wrong framework for modal epistemology and that a certain nonreductionist approach to the theory of concepts and propositions is required instead. Finally, there is an examination of moderate rationalism’s impact on modal arguments in the philosophy of mind -- for example, Yablo’s disembodiment argument and (...) Chalmers’s zombie argument. A less vulnerable style of modal argument is defended, which nevertheless wins the same anti-materialist conclusions sought by these other arguments. (shrink)

This dissertation contains four independent essays addressing a cluster of related topics in the philosophy of mind. Chapter 1: “Fundamentality Physicalism” argues that physicalism can usefully be conceived of as a thesis about fundamentality. The chapter explores a variety of other potential formulations of physicalism (particularly modal formulations), contrasts fundamentality physicalism with these theses, and offers reasons to prefer fundamentality physicalism over these rivals. Chapter 2:“Modal Rationalism and the Demonstrative Reply to the Master Argument Against Physicalism” introduces (...) the Master Argument Against Physicalism and investigates its crucial premise: the inference from an a priori gap between the physical and consciousness to a lack of necessitation between the two. I argue against the strong form of modal rationalism that underwrites the master argument and offer a more moderate rationalist view. I offer a novel demonstrative reply to the master argument, according to which a connection between conscious experience and demonstratives, not dualism, is the source of the epistemic gap between consciousness and the physical. Chapter 3: “Conceptual Mastery and the Knowledge Argument” argues that Frank Jackson’s famous anti-physicalist knowledge argument featuring Mary, a brilliant neuroscientist raised in a black and white room, founders on a dilemma. Either (i) Mary cannot know the relevant experiential truths because of trivial obstacles that have no bearing on the truth of physicalism or (ii) once the obstacles have been removed, Mary can know the relevant truths. Chapter 4: “Toward a Theory of Conceptual Mastery” investigates the question “Under what conditions does a thinker fully understand, or have mastery of, a concept?” I argue against three views of conceptual mastery, according to which conceptual mastery is a matter of holding certain beliefs, being disposed to make certain inferences, or having certain intuitions. I propose and respond to objections to my own “meaning postulate view” of the conditions under which a thinker has mastery of a concept. (shrink)

This collection highlights the new trend away from rationalism and toward empiricism in the epistemology of modality. Accordingly, the book represents a wide range of positions on the empirical sources of modal knowledge. Readers will find an introduction that surveys the field and provides a brief overview of the work, which progresses from empirically-sensitive rationalist accounts to fully empiricist accounts of modal knowledge. Early chapters focus on challenges to rationalist theories, essence-based approaches to modal knowledge, and (...) the prospects for naturalizing modal epistemology. The middle chapters present positive accounts that reject rationalism, but which stop short of advocating exclusive appeal to empirical sources of modal knowledge. The final chapters mark a transition toward exclusive reliance on empirical sources of modal knowledge. They explore ways of making similarity-based, analogical, inductive, and abductive arguments for modal claims based on empirical information. Modal epistemology is coming into its own as a field, and this book has the potential to anchor a new research agenda. (shrink)

The article argues against attempts to combine ontological realism about modality with the rejection of modal rationalism and it suggests that modal realism requires modal rationalism. /// El artículo da argumentos en contra de que se intente combinar el realismo ontológico sobre la modalidad con el rechazo del racionalismo modal y sugiere que el realismo modal exige racionalismo modal.

Metaphysical rationalism, the doctrine which affirms the Principle of Sufficient Reason (the PSR), is out of favor today. The best argument against it is that it appears to lead to necessitarianism, the claim that all truths are necessarily true. Whatever the intuitive appeal of the PSR, the intuitive appeal of the claim that things could have been otherwise is greater. This problem did not go unnoticed by the great metaphysical rationalists Spinoza and Leibniz. Spinoza’s response was to embrace necessitarianism. (...) Leibniz’s response was to argue that, despite appearances, rationalism does not lead to necessitarianism. This paper examines the debate between these two rationalists and concludes that Leibniz has persuasive grounds for his opinion. This has significant implications both for the plausibility of the PSR and for our understanding of modality. (shrink)

Accounting for our knowledge of de re modalities is probably the main reason why the proponents of modal empiricism think that their view should be preferred to modal rationalism. In this paper, I address Sonia Roca-Royes' account, which is taken to be a representative modal empiricist view, in order to show that modal empiricism faces serious problems even in explaining our knowledge of possibility de re, something which seems to be the easiest thing to explain (...) on this view. I argue that Roca-Royes' account does not prove what she claims it does, that it can hardly be articulated in a non-redundant way, and that her account of our knowledge of possibility de re can hardly be reconciled with the essentiality of origin principle, to which modal empiricists sometimes appeal while criticizing the modal rationalist account. (shrink)

This article proposes a way of blocking the zombie argument against materialism. The central idea—which can be motivated in various ways, but which I will motivate by drawing on recent work by Wolfgang Schwarz—is that sentences reporting conscious experience are modally inert, roughly in the sense that adding them to a description of a metaphysically possible scenario always results in a description of a metaphysically possible scenario. This is notable in that it leads to a way of blocking the zombie (...) argument, which is perfectly compatible with modal rationalism and with the view that conceivability entails possibility. (shrink)

The paper explores the project of an ambitious modal epistemology that attempts to combine the a priori methods of Chalmers’ 2D semantics with Kripke’s modal metaphysics. I argue that such a project is not viable. The ambitious modal epistemology involves an inconsistent triad composed of (1) Modal Monism, (2) Two-Dimensionalism, and what I call (3) “Metaphysical Kripkeanism”. I present the three theses and show how only two of those can be true at a time. There is (...) a fundamental incompatibility between Chalmers’ Modal Rationalism and Kripke’s modal metaphysics. Specifically, Chalmers’ conceivability entails possibilities that a Kripkean rejects as genuinely metaphysical. However, three positive stances in modal epistemology emerge from the combinations that the triad allows. One of those offers a promising way forward for 2D modal epistemologies. But it comes with a cost, as it requires abandoning modal monism and reshaping the scope of what a priori conceivability can give us access to. (shrink)

Modal rationalists uphold a strong constitutive relationship between a priori cognition and modal cognition. Since both a priori cognition and modal cognition have been taken to be characteristic of philosophical insights, I will critically assess an ambitious modal rationalism and an associated ambitious methodological rationalism. I begin by examining Kripkean cases of the necessary a posteriori in order to characterize the ambitious modal rationalism that will be the focus of my criticism. I (...) then argue that there is a principled association between this view in the epistemology of modality and an ambitious methodological rationalist picture of the nature of philosophical insights. On the basis of this discussion, I criticize ambitious modal rationalism and argue that the critique indicates some principled limits of generating philosophical insights by a priori modal cognition. Hence, my central diagnosis is that ambitious methodological rationalists are overly ambitious in the role that they assign a priori modal cognition in philosophical methodology. -/-. (shrink)

Kant contends that necessity is a criterion of the a priori—that is, that all knowledge of necessary propositions is a priori. This contention, together with two others that Kant took to be evident—we know some mathematical propositions and such propositions are necessary—leads directly to the conclusion that some knowledge is a priori. Although many contemporary philosophers endorse Kant’s criterion, supporting arguments are hard to come by. Gordon Barnes provides one of the few examples. My purpose in this chapter is to (...) articulate and examine his argument. I have two goals in doing so. The first is to uncover several significant gaps in the argument. The second is to show that it suffers from a common defect in rationalist arguments. If the argument were successful against empiricist accounts of modal knowledge, it would apply with equal force to extant rationalist accounts of such knowledge. Hence, the cost of refuting modal empiricism is modal scepticism. (shrink)

My goal in this paper is to show that Kant’s prohibition on certain kinds of knowledge of things-in-themselves is motivated less by his anti-soporific encounter with Hume than by his new view of the distinction between “real” and “logical” modality, a view that developed out of his reflection on the rationalist tradition in which he was trained. In brief: at some point in the 1770’s, Kant came to hold that a necessary condition on knowing a proposition is that one be (...) able to prove that all the items it refers to are either really possible or really impossible. Most propositions about things-in-themselves, in turns out, cannot meet this condition. I conclude by suggesting that the best interpretation of this modal condition is as a kind of coherentist constraint. (shrink)

This collection highlights the new trend away from rationalism and toward empiricism in the epistemology of modality. Accordingly, the book represents a wide range of positions on the empirical sources of modal knowledge. Readers will find an introduction that surveys the field and provides a brief overview of the work, which progresses from empirically-sensitive rationalist accounts to fully empiricist accounts of modal knowledge. Early chapters focus on challenges to rationalist theories, essence-based approaches to modal knowledge, and (...) the prospects for naturalizing modal epistemology. The middle chapters present positive accounts that reject rationalism, but which stop short of advocating exclusive appeal to empirical sources of modal knowledge. The final chapters mark a transition toward exclusive reliance on empirical sources of modal knowledge. They explore ways of making similarity-based, analogical, inductive, and abductive arguments for modal claims based on empirical information. Modal epistemology is coming into its own as a field, and this book has the potential to anchor a new research agenda. (shrink)

In Epistemic Two-Dimensional Semantics, David Chalmers seeks to develop a version of 2-D semantics which can vindicate the rationalist claim that there are constitutive connections between meaning, possibility and a priority. Chalmers lays out different ways of filling in his preferred epistemic approach to 2-D semantics so as to avoid controversial philosophical assumptions. In these comments, however, I argue that there are some distinctively rationalist commitments in Chalmers's epistemic approach to 2-D semantics. I start by explaining why Chalmers's approach requires (...) a canonical language that affords subjects accurate a priori access to the space of possibility. I then argue that traditional worries about rationalism will simply re-emerge as worries about whether there can be a canonical vocabulary and how we could come to recognize one if there were. The moral is that Chalmers's 2-D semantic framework builds in substantive metaphysical and epistemological commitments which stand in need of further defense. (shrink)

Kant rejects the ontological argument on the grounds that the ontological argument inescapably must assume that existence is a “determination” or “real predicate,” which it is not. Most understand Kant’s argument for this claim to be premised upon his distinctive proto-Fregean theory of existence. But this leaves Kant dialectically vulnerable: the defender of the ontological argument can easily reject this as question-begging. I show that Kant relies upon two distinct arguments, both of which contend that the claim that existence is (...) a determination is inconsistent with bedrock ontological set pieces assumed by rationalist defenders of the ontological argument. (shrink)

The paper argues against Peacocke's moderate rationalism in modality. In the first part, I show, by identifying an argumentative gap in its epistemology, that Peacocke's account has not met the Integration Challenge. I then argue that we should modify the account's metaphysics of modal concepts in order to avoid implausible consequences with regards to their possession conditions. This modification generates no extra explanatory gap. Yet, once the minimal modification that avoids those implausible consequences is made, the resulting account (...) cannot support Peacocke's moderate rationalism. (shrink)

Recent work on the imagination has stressed the epistemic significance of imaginative experiences, notably in justifying modal beliefs. An immediate problem with this is that modal beliefs appear to admit of justification through the mere exercise of rational capacities. For instance, mastery of the concepts of square, circle, and possibility should suffice to form the justified belief that a square circle is not possible, and mastery of the concepts of pig, flying, and possibility should suffice to form a (...) justified belief that a flying pig is possible. It is thus unnecessary to try to imagine a square circle or a flying pig to justify these beliefs. In this paper, I consider three ways to defend the epistemic role of imagination in modal epistemology against this challenge. One claims that modal beliefs simply admit of justification by two separate sources: rational capacities and imaginative experience. Another holds that while beliefs about logical or conceptual modality can be justified entirely by rational capacities, beliefs about metaphysical modality require imaginative experiences. The third, which I defend, is the idea that imagination is relevant in the first instance not to modal knowledge but to modal understanding: even where imaginative experience is unnecessary for the justification of modal beliefs, it is indispensable for directly grasping certain modal propositions. (shrink)

Modal dualism is the claim that there is a space of epistemically possible worlds that exceeds the space of metaphysically possible worlds. In the present paper, I argue that modal dualism is false. I do so via an argument that differs from most previous arguments against modal dualism in that it does not rely on controversial semantic or epistemological assumptions like descriptivism, internalism or modal rationalism. The point of my argument is, instead, that modal (...) dualism is internally inconsistent because it is the result of the failure to draw the proper conclusions from the abandonment of these semantic and epistemological assumptions. The relevant inconsistency manifests itself in the modal dualist notion of epistemic modality. For this notion to play the explanatory roles assigned to it by modal dualists, it has to be a notion of a genuinely epistemic kind of modality. But the only way to make sense of such a notion is via just those semantic or epistemological assumptions that the modal dualist is keen to avoid. Anyone willing to abandon these assumptions has to go further and detach the epistemic from the modal altogether. (shrink)

The philosophy of necessity and possibility has flourished in the last half-century, but much less attention has been paid to the question of how we know what can be the case and what must be the case. Many friends of modal metaphysics and many enemies of modal metaphysics have agreed that while empirical discoveries can tell us what is the case, they cannot shed much light on what must be the case or on what non-actual possibilities there are. (...) In this paper, in contrast, I discuss and defend naturalistic approaches to discovering the facts about necessity and possibility. After some remarks about what methodological naturalism in philosophy might amount to, I argue that naturalistic method in modal investigations may not need to be particularly revisionary of much of what is currently being done in modal investigation. I then discuss a number of respects in which a naturalistic orientation in modal investigation may improve on our current epistemic situation. (shrink)

What follows are compressed versions of three lectures on the subject of "Mind and Modality", given at Princeton University the week of October 12-16, 1998. The first two form a series; the third stands alone to some extent. All are philosophically technical, and probably of interest mainly to philosophers. I hope that they make sense, at least to those familiar with my book _The Conscious Mind_ . Lecture 1 recapitulates some of the material in the book in a somewhat different (...) form, and adds some further material on conditionals and on Kripke. Note that section has a more or less definitive formalization of the anti-materialist argument from the book . Lecture 2 pushes deeper into the heart of modality, further investigating the conceivability/possibility relationship and the epistemology of modality , and arguing for a sort of modal rationalism. Lecture 3 gives an analysis of the content of beliefs about experiences, and applies this to a number of epistemological issues, including incorrigibility and the dialectic on "The Myth of the Given". (shrink)

My topic is moderate modal skepticism in the spirit of Peter van Inwagen. Here understood, this is a conservative version of modal empiricism that severely limits the extent to which an ordinary agent can reasonably believe “exotic” possibility claims. I offer a novel argument in support of this brand of skepticism: modal skepticism grounds an attractive (and novel) reply to Humean skepticism. Thus, I propose that modal skepticism be accepted on the basis of its theoretical utility (...) as a tool for dissolving philosophical paradox. (shrink)

This paper examines Descartes' controversial theory of the creation of eternal truths and the views of modality attributed to Descartes in recent interpretations of it. It shows why attempts to make Descartes' view intelligible by distinctions of different kinds of modality fail to do justice to his theory, which is radical indeed without being incoherent or involving universal possibilism or irrationalism. Descartes' opposition to traditional rationalist views of modality, it suggests, can be seen instead as foreshadowing contemporary views prefixed, logical (...) structure of reality or of the divine intellect. (shrink)

The chapter defends an evolutionary explanation of modal knowledge from knowledge of counterfactual conditionals. Knowledge of counterfactuals is evolutionarily useful, as it enables us to learn from mistakes. Given the standard semantics for counterfactuals, there are several equivalences between modal claims and claims involving counterfactuals that can be used to explain modal knowledge. Timothy Williamson has suggested an explanation of modal knowledge that draws on the equivalence of ‘Necessarily p’ with ‘If p were false, a contradiction (...) would be the case’. He postulates a cognitive process that draws on this equivalence and that is supposed to underlie our modal judgements. The existence of this cognitive process would, however, have consequences that conflict with results from empirical psychology. The chapter argues that the equivalence of ‘Necessarily p’ with ‘For all q, if q were true then p would be true’ should instead be used to explain knowledge of necessity. This explanation requires giving an account of how we know truths of the form ‘For all q, if q were true then p would be true’. In order to provide such an account, the chapter draws on a different suggestion by Williamson about knowledge of generalizations. According to this suggestion, we come to know truths of the form ‘All Fs are G’ by imagining a generic F and judging that it is G. Applied to our case, the suggestion would be that we come to know that p is counterfactually implied by all propositions (and hence that p is necessary) by entertaining a generic proposition and judging that it counterfactually implies p. It would even suffice to entertain a generic possible proposition and judge that it counterfactually implies p, for it can be shown that the claim ‘For all possible q, if q were true then p would be true’ is equivalent to the original claim ‘For all q, if q were true then p would be true’ and hence is equivalent to ‘Necessarily p’. It might seem that, from an evolutionary perspective, probabilistic reasoning is just as useful as reasoning involving counterfactuals. The chapter argues, however, that this would not undermine the envisaged explanation of modal knowledge. The chapter concludes by suggesting avenues of empirical research that might shed light on the cognitive processes that actually underlie our evaluations of modal claims and on the relation between these processes and those involved in counterfactual reasoning. The results of such empirical research would be highly relevant epistemologically, since they will ultimately determine which (if any) equivalence between modal claims and claims involving counterfactuals should be used to explain our modal knowledge. (shrink)

The subject of this dissertation is the entitlement to modal beliefs, such as the belief that a proposition is necessarily true, or the belief that a proposition is possibly true. My thesis is that the entitlement to modal beliefs has two dimensions, one active and one passive. In the active dimension, someone is entitled to a modal belief just in case he has conducted the appropriate thought experiments. In the passive dimension, someone is entitled to a (...) class='Hi'>modal belief just in case the belief fits his evidence, which is constituted by the conceivability or inconceivability of the proposition in question. Thus, my principal contention is that conducting thought experiments, and taking conceivability as evidence of possibility, is both necessary and sufficient for entitled modal belief. Insofar as these methods are a priori, this implies that our entitlement to our modal beliefs is always partially a priori. ;I begin by clarifying the fundamental concepts of entitlement, modality, and apriority. Then I proceed to state and defend a two-dimensional account of the necessary a posteriori. According to such an account, our entitlement to every necessary a posteriori truth is achieved by an a priori deduction from two or more claims, at least one of which is a priori. The a priori dimension of this entitlement involves the very same methods and sources of entitlement as other modal beliefs---thought experiments and states of conceivability or inconceivability. I go on to defend thought experiments and conceivability against skeptical attacks. Much of the criticism of thought experiments turns on a refusal to countenance the relevant sort of modality. However, I defend this sort of modality in an opening chapter of the dissertation. Much skepticism about the epistemic value of conceivability is founded on an illicit demand for a noncircular demonstration of its reliability. However, if universally accepted, this demand would undercut the evidence of the senses as well. Other objections to conceivability are also considered and found wanting. In conclusion, I argue against conventionalism about modality, and defend a form of rationalism in modal epistemology. (shrink)

David Chalmers supports his contention that there is a possible world populated by our zombie twins by arguing for the assumption that conceivability entails possibility. But, I argue, the modal epistemology he sets forth, ‘modal rationalism,’ ignores the problem of incompleteness and relies on an idealized notion of conceivability. As a consequence, this epistemology can’t justify our quotidian judgments of possibility, let alone those judgments that concern the mind/body connection. Working from the analogy that the imagination is (...) to the possible as perception is to the actual, I set forth a competing epistemology, ‘modal empiricism.’ This epistemology survives the incompleteness objection and allows some of our everyday modal judgments to be justified. But this epistemology can’t justify the claim that Zombie World is possible, which leaves Chalmers’s property dualism without the support it needs. (shrink)

Leibniz: Modal Metaphysics Gottfried Wilhelm Leibniz (1646-1716) served as the natural end of the rationalist tradition on the European continent, which included Descartes, Spinoza, and Malebranche. His philosophy was one of the major influences on Kant. Although Leibniz had many philosophical and intellectual interests, he was arguably most concerned with reconciling the freedom required for … Continue reading Leibniz: Modal Metaphysics →.

In the Critique of Pure Reason, following his elucidation of the ‘postulates’ of possibility, actuality, and necessity, Kant makes a series of puzzling remarks. He seems to deny the somewhat metaphysically intuitive contention that the extension of possibility is greater than that of actuality, which, in turn, is greater than that of necessity. Further, he states that the actual adds nothing to the possible. This leads to the view, fairly common in the literature, that Kant holds that all modal (...) categories, in their empirical applications, are coextensive. I diverge from the common view. First, Kant is not committed to the coextensiveness thesis, understood as above. Instead, he espouses a weaker, epistemological version of the coextensiveness thesis, namely that what we can assert to be really possible is coextensive with what we cognize to be actual. Second, Kant's remarks are not intended to introduce a positive ontological thesis about the extensions of modal categories. Rather, he means to criticize a certain conception of modalities that was prevalent among his rationalist predecessors, i.e., the conception of modalities as various determinations that enter the intensions of concepts of things. (shrink)

According to modal empiricism, our justification for believing possibility and necessity claims is a posteriori. That is, experience does not merely play an enabling role in modal justification; it isn’t simply that experience explains how, say, we acquire the relevant concepts. Rather, the view is that modal claims answer to the tribunal of experience in roughly the way that claims about quarks and quails answer to it. One serious objection to modal empiricism is the problem of (...) empirical conservativeness: it doesn’t seem that experience can distinguish between modal claims. And if experience can’t manage that, it’s hard to see how it can provide evidence for one claim over the other. So if modal empiricism is true, we ought to be modal skeptics. On the assumption that we shouldn’t be modal skeptics, we should reject modal empiricism. I have two aims here: first, to reply to this objection to modal empiricism; second, to sketch a modal epistemology that fits with the reply I offer. (shrink)

The many worlds anthropic principle is explored here from the a priori perspective of rationalist metaphysics, within the framework of modal logic. It is shown how the apparent contradictions of quantum superposition can be thought of in terms of different levels of world models. The framework of modal logic is used, but given the rationalist assumption that all possible worlds exist. There is thus no absolute distinction between possibility and necessity. To take the point of view of a (...) conscious being in a world, however, is to adopt some such distinction--something we must do in order to do physics. This paper is intended to lay the groundwork for future attempts to develop theories of what is necessarily true in a world with conscious entities. It also contains some tentative speculations on the difficult issue of death and quantum mechanics. (shrink)

This essay expands upon the suggestion that Lessing's infamous ‘ditch’ is actually three ditches: temporal, metaphysical, and existential gaps. It examines the complex problems these ditches raise, and then proposes that Kierkegaard's Fragments and Postscript exhibit a similar triadic organizational structure, which may signal a deliberate attempt to engage and respond to Lessing's three gaps. Viewing the Climacean project in this way offers an enhanced understanding of the intricacies of Lessing's rationalist approach to both religion and historical truth, and illuminates (...) Climacus's subjective response to Lessing. (shrink)

This book defends a radical new theory of contingency as a physical phenomenon. Drawing on the many-worlds approach to quantum theory and cutting-edge metaphysics and philosophy of science, it argues that quantum theories are best understood as telling us about the space of genuine possibilities, rather than as telling us solely about actuality. When quantum physics is taken seriously in the way first proposed by Hugh Everett III, it provides the resources for a new systematic metaphysical framework encompassing possibility, necessity, (...) actuality, chance, counterfactuals, and a host of related modal notions. -/- Rationalist metaphysicians argue that the metaphysics of modality is strictly prior to any scientific investigation; metaphysics establishes which worlds are possible, and physics merely checks which of these worlds is actual. Naturalistic metaphysicians respond that science may discover new possibilities and new impossibilities. This book's quantum theory of contingency takes naturalistic metaphysics one step further, allowing that science may discover what it is to be possible. As electromagnetism revealed the nature of light, as acoustics revealed the nature of sound, as statistical mechanics revealed the nature of heat, so quantum physics reveals the nature of contingency. (shrink)

The paper focuses on the Epistemic Challenge for mind-independent accounts of modality. The challenge can be formulated as an inconsistency problem among three premises and, therefore, any strategy to meet the challenge will require the negation of (at least) one of its premises. The aim of the paper is not to offer a positive solution to the challenge, but rather to argue for the claim that to follow a hybrid strategy is probably the best way to meet it. With some (...) qualifications, reasons are given as to why empiricism should be the way to meet the challenge as far as de re modality is concerned, whereas rationalism might be the correct way of addressing it for the case of de dicto modality. (shrink)

A striking feature of the traditional armchair method of philosophy is the use of imaginary examples: for instance, of Gettier cases as counterexamples to the justified true belief analysis of knowledge. The use of such examples is often thought to involve some sort of a priori rational intuition, which crude rationalists regard as a virtue and crude empiricists as a vice. It is argued here that, on the contrary, what is involved is simply an application of our general cognitive capacity (...) to handle counterfactual conditionals, which is not exclusively a priori and is not usefully conceived as a form of rational intuition. It is explained how questions of metaphysical possibility and necessity are equivalent to questions about counterfactuals, and the epistemology of the former (in particular, the role of conceiving or imagining) is a special case of the epistemology of the latter. A non-imaginary Gettier case is presented in order to show how little difference it makes. (shrink)

I propose a new reading of Hegel’s discussion of modality in the ‘Actuality’ chapter of the Science of Logic. On this reading, the main purpose of the chapter is a critical engagement with Spinoza’s modal metaphysics. Hegel first reconstructs a rationalist line of thought — corresponding to the cosmological argument for the existence of God — that ultimately leads to Spinozist necessitarianism. He then presents a reductio argument against necessitarianism, contending that as a consequence of necessitarianism, no adequate explanatory (...) accounts of facts about finite reality can be given. (shrink)