Accuracy, probabilism, and the insufficiency of the alethic

The best and most popular argument for probabilism is the accuracy-dominance argument, which purports to show that alethic considerations alone support the view that an agent’s degrees of belief should always obey the axioms of probability. I argue that extant versions of the accuracy-dominance argument face a problem. In order for the mathematics of the argument to function as advertised, we must assume that every omniscient credence function is classically consistent; there can be no worlds in the set of dominance-relevant worlds that obey some other logic. This restriction cannot be motivated on alethic grounds unless we’re also willing to accept that rationality requires belief in every metaphysical necessity, as the distinction between a priori logical necessities and a posteriori metaphysical ones is not an alethic distinction. To justify the restriction to classically consistent worlds, non-alethic motivation is required. And thus, if there is a version of the accuracy-dominance argument in support of probabilism, it isn’t one that is grounded in alethic considerations alone.

Rejecting Iteration

This is the first of two chapters exploring the option of resolving various Tolerance Puzzles by denying Iteration, the claim that whatever is possibly possible is possible. In this chapter we grant for the sake of argument that Iteration fails for metaphysical necessity, and consider whether there are other Tolerance Puzzles which remain problematic even on that assumption. Our main focus is on puzzles involving ancestral metaphysical possibility—the status of being either possible, or possibly possible, or possibly possibly possible, or…—for which Iteration is guaranteed by our basic modal logic. We argue that plausible higher-order identities suggest that ancestral metaphysical possibility is not a trivial status even for those who deny Iteration for metaphysical possibility.

Iteration for Metaphysical Necessity

This is the second of two chapters exploring the option of resolving various Tolerance Puzzles by denying Iteration, the claim that whatever is possibly possible is possible. This chapter argues for Iteration for metaphysical possibility, based on the premise that metaphysical possibility is the broadest form of possibility. Some reject this on the grounds that, for example, it is logically possible (although metaphysically impossible) that Hesperus is distinct from Phosphorus. We show that those who accept this premise should reject the form of existential generalization required to derive the conclusion that there is a form of possibility that attaches to the proposition that Hesperus is distinct from Phosphorus. We show how under certain attractive assumptions about the grain of higher-order reality one can show that there is a broadest form of possibility, and indeed define it in purely logical terms.

Two Crises for the Proof Paradigm in the Enlightenment

In Chapter 2, the author critically discusses the epistemologies of David Hume and Immanuel Kant. The author distinguishes the skeptical Hume from the naturalist Hume. The author presents the skeptical Hume’s philosophy as a response to what he calls Berkeley’s puzzle. He argues that Hume’s skeptical arguments are self-refuting and self-undermining and that Hume’s analysis of cause is an example of an explanation-impairing framework substitution. Hume’s solution to his skeptical arguments was a new kind of epistemology, a naturalistic epistemology. The author presents Kant’s epistemology as a response to the state of rationalist metaphysics at the time of Kant’s first Critique. Kant’s epistemology was similar to Hume’s in one important respect. Just as Hume had psychologized the idea of causal necessity, Kant psychologized the idea of metaphysical necessity. The author argues that both solutions were a form of relativism. This chapter primarily serves to motivate a search for a non-skeptical, non-relativist, non-Platonist theory of epistemic rationality.

The Unity of the Rational Mind

I argue that inference is a self-conscious act. The account appeals to the ‘being-in-mind-together’ of beliefs. Beliefs that are in mind together are subject to rationally grounded metaphysical necessity. Because one believes p, one can’t or must believe q. But what ultimately explains this sort of necessity? If it is impossible to hold a pair of mental states in mind at once and the impossibility has its source in our understanding of the necessary falsehood of a conjunction, then the subject has knowledge not just of the individual states they’re in but also of their combination. What, then, is the relation between the unity of our beliefs and consciousness of this unity? My answer: the unity of the rational mind consists in the subject’s consciousness of that unity.

Asymmetry cannot solve the circularity/regress problem of property structuralism

Strong dispositional monism (SDM), the position that all fundamental physical properties consist in dispositional relations to other properties, is naturally construed as property structuralism. J. Lowe’s circularity/regress objection (CRO) constitutes a serious challenge to SDM that questions the possibility of a purely relational determination of all property essences. The supervenience thesis of A. Bird’s graph-theoretic asymmetry reply to CRO can be rigorously proved. Yet the reply fails metaphysically, because it reveals neither a metaphysical determination of identities on a purely relational basis nor a determination specifically of identities in the sense of essences. Asymmetry is thus not by itself sufficient for a solution to CRO. But it cannot even help to answer CRO when a model for the determination of essences is taken as a basis. Nor is asymmetry necessary for a reply, as property structures may well be symmetric. A metaphysics of dispositional properties as grounded in a purely relational structure faces serious obstacles, and the properties would not be fundamental. Since essence and grounding are notions of metaphysical priority, there can be no essentially dispositional metaphysically fundamental properties, and the prospects of a “coherentist” metaphysics of basic properties are dim. A modal retreat that refrains from a post-modal conception of essence and simply claims that fundamental properties play dispositional roles by metaphysical necessity is unsatisfactory.

Newton’s Modal Metaphysics and Polemics with Spinozism in the “General Scholium”

This chapter is devoted to explaining the nature and use of metaphysical necessity in Newton’s “General Scholium.” In particular, it focuses on Newton’s metaphysical commitments about (i) the nature of modality; (ii) the nature of formal causation; and (iii) God’s existence. In order to explain these, the chapter draws on Clarke and Clarke’s subsequent correspondence with Joseph Butler. In order to clarify some philosophical distinctions, I treat Toland’s Spinozism, in particular, as the target of some of Newton’s arguments. Along the way, I’ll provide suggestive evidence that Newton was in a decent position to distinguish the thought of Descartes from Spinozism

Kripke’s metaphysical necessity: a Kantian perspective

Este artigo estuda o conceito de necessidade em O Nomear e a necessidade de Kripke. Kripke distingue necessidade metafísica de necessidade epistemológica. Portanto, posições neoclássicas e neoempiristas estão erradas, porque permanecem no domínio epistemológico. Em Kripke, a epistemologia se torna uma investigação psicológica sobre o conhecimento individual. Não pode lidar com o problema da justificação e, portanto, não pode explicar por que existem proposições necessariamente verdadeiras. Quando ele tenta fazer isso, cai na armadilha da dialética, como Kant alertara. Finalmente, o artigo defende que o domínio metafísico é apenas uma abstração baseada em uma epistemologia objetiva.

The Modal Status of Moral Principles

Conventional wisdom holds that pure moral principles hold of metaphysical necessity, from which it follows that it is metaphysically impossible for the moral facts to vary independently of the descriptive facts. Moral contingentists deny this, holding that the moral laws are in some cases like the laws of nature: metaphysically contingent, but necessary in a weaker sense. The present chapter makes a preliminary case for moral contingentism and defends the view against recent objections due to Lange (2018) and Dreier (2019).

Necessitism, Contingentism, and Theory Equivalence

Necessitism, Contingentism, and Theory Equivalence is a dissertation on issues in higher-order modal metaphysics. Consider a modal higher-order language with identity in which the universal quantifier is interpreted as expressing (unrestricted) universal quantification and the necessity operator is interpreted as expressing metaphysical necessity. The main question addressed in the dissertation concerns the correct theory formulated in this language. A different question that also takes centre stage in the dissertation is what it takes for theories to be equivalent.The whole dissertation consists of an extended argument in defence of the (joint) truth of two seemingly inconsistent higher-order modal theories, specifically: 1.Plantingan Moderate Contingentism, a theory based on Plantinga’s [1] modal metaphysics that is committed to, among other things, the contingent being of some individuals and the necessary being of all possible higher-order entities;2.Williamsonian Thorough Necessitism, a theory advocated by Williamson [3] which is committed to, among other things, the necessary being of every possible individual as well as of every possible higher-order entity.Part of the case for these theories’ joint truth relies on defences of the following metaphysical theses: (i) Thorough Serious Actualism, the thesis that no things could have been related while being nothing, and (ii) Higher-Order Necessitism, the thesis that necessarily, every higher-order entity is necessarily something. It is shown that Thorough Serious Actualism and Higher-Order Necessitism are both implicit commitments of very weak logical theories. The defence of Higher-Order Necessitism constitutes a powerful challenge to Stalnaker’s [2] Thorough Contingentism, a theory committed to, among other things, the view that there could have been some individuals as well as some entities of any higher-order that could have been nothing.In the dissertation it is argued that Plantingan Moderate Contingentism and Williamsonian Thorough Necessitism are in fact equivalent, even if they appear to be jointly inconsistent. The case for this claim relies on the Synonymy account, a novel account of theory equivalence developed and defended in the dissertation. According to this account, theories are equivalent just in case they have the same commitments and conception of logical space.By way of defending the Synonymy account’s adequacy, the account is applied to the debate between noneists, proponents of the view that some things do not exist, and Quineans, proponents of the view that to exist just is to be some thing. The Synonymy account is shown to afford a more nuanced and better understanding of that debate by revealing that what noneists and Quineans are really disagreeing about is what expressive resources are available to appropriately describe the world.By coupling a metatheoretical result with tools from the philosophy of language, it is argued that Plantingan Moderate Contingentism and Williamsonian Thorough Necessitism are synonymous theories, and so, by the lights of the Synonymy account, equivalent. Given the defence of their extant commitments made in the dissertation, it is concluded that Plantingan Moderate Contingentism and Williamsonian Thorough Necessitism are both correct. A corollary of this result is that the dispute between Plantingans and Williamsonians is, in an important sense, merely verbal. For if two theories are equivalent, then they “require the same of the world for their truth.”Thus, the results of the dissertation reveal that if one speaks as a Plantingan while advocating Plantingan Moderate Contingentism, or as a Williamsonian while advocating Williamsonian Thorough Necessitism, then one will not go wrong. Notwithstanding, one will still go wrong if one speaks as a Plantingan while advocating Williamsonian Thorough Necessitism, or as a Williamsonian while advocating Plantingan Moderate Contingentism.On the basis of a conception of the individual constants and predicates of second-order modal languages as strongly Millian, i.e., as having actually existing entities as their semantic values, in the appendix are presented second-order modal logics consistent with Stalnaker’s Thorough Contingentism. Furthermore, it is shown there that these logics are strong enough for applications of higher-order modal logic in mathematics, a result that constitutes a reply to an argument to the contrary by Williamson [3]. Finally, these logics are proven to be complete relative to particular “thoroughly contingentist” classes of models.