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.

The Metaphysical Possibility of Time Travel Fictions

In some stories, time travellers cannot change the past. It is widely accepted that this is metaphysically possible. In some stories, time travellers can change the past. Many philosophers have explained how that, too, is metaphysically possible. This paper considers narratives where sometimes the past can change and sometimes it cannot, arguing that this is also something that is possible. Further, I argue that we can make sense of stories where some events appear to be ‘fixed points in time’.

Competing views

The present account, which construes justification as a kind of epistemic possibility of knowing, or of being in a position to know, competes with three recently advanced theories of justification. Of these competitors, the first two construe doxastic justification as the metaphysical possibility of knowing. While they differ in some details, these views share certain problematic features: they fail to yield a corresponding account of propositional justification, have trouble vindicating an intuitive principle of closure for justified belief, and fail to comply with the independently plausible principle that if one has a justified belief, one is in no position to rule out that one has knowledge. The present account does not have these problematic features. According to the third competitor, |φ‎| is propositionally justified in one’s situation just in case it would be abnormal—and so require explanation—if |φ‎| were to be false in the presence of the evidence that one possesses in that situation. This normic theory of justification validates the principle that propositional justification agglomerates over conjunction, and in so doing, violates the constraint that propositions of the form ⌜φ‎ & ¬Kφ‎⌝ never be justified. It likewise contradicts the independently plausible principle that whenever |φ‎| is propositionally justified all things considered, |¬Kφ‎| is not. The present account does not face these problems, since it rejects the relevant agglomeration principle and treats the condition encoded by ⌜¬K¬Kφ‎⌝ as luminous.

Justification as Ignorance

Justification as Ignorance offers an original account of epistemic justification as both non-factive and luminous that vindicates core internalist intuitions, without construing justification as an internal condition. The account conceives of justification, in its doxastic and propositional varieties, as a kind of epistemic possibility of knowing, and of being in a position to know, respectively. It thus contrasts with other recently proposed views that characterize justification in terms of the metaphysical possibility of knowing. In developing his account, Rosenkranz devises a suitable non-normal multi-modal epistemic logic for knowledge and being in a position to know that respects the finding that these notions create hyperintensional contexts, defends his conception of justification against well-known anti-luminosity arguments, shows that the account allows for fruitful applications and principled solutions to the lottery and preface paradoxes, and provides a metaphysics of justification, and of its varying degrees of strength, that is compatible with core assumptions of the knowledge-first approach and disjunctivist conceptions of mental states.

Outline of a theory of justification

Core theses of the novel account of justification to be developed are first stated: one has propositional justification for p just in case one is in no position to know that one is in no position to know p; and one has doxastic justification for p just in case one is in no position to know that one does not know p. Unlike other theories that conceive of justification in terms of the metaphysical possibility of knowing, the present account thus construes it as a distinctive kind of epistemic possibility. It treats propositional justification as non-factive, both its presence and its absence as luminous conditions, and by assuming a weak non-normal modal logic for knowledge and being in a position to know, validates principles of positive and negative introspection for it. The account thereby attributes features to justification that internalists care about. But it does so without construing justification as an internal condition. The account allows one to systematically distinguish between the condition of being justified and the metaphysical grounds for its obtaining, thereby heeding externalist insights into the difference between the good cases and the bad cases envisaged by radical scepticism. Lines of argument that show the account’s potential, e.g. in dealing with the preface and lottery paradoxes, are previewed, and so are lines of defence against challenges and objections, including prominent anti-luminosity arguments.

Panpsychism and Spiritual Flourishing: Constructive Engagement with the New Science of Psychedelics

This article discusses the potential implications of panpsychism for the study and pursuit of spiritual flourishing, with a focus on emerging scientific and philosophical research on psychedelics. Psychedelics research (1) has the means to reliably and safely produce the conditions in which transformative experiences routinely occur, thereby allowing for robust neuroscientific and psychological research, and (2) has attracted a growing body of philosophical and theological work on the metaphysical and epistemological possibilities of such experiences. I begin with a discussion of recent scientific work on psychedelics. I then discuss the epistemic status of psychedelic experiences, where the metaphysics of panpsychism is particularly interesting. I suggest there exists a mutually reinforcing relationship between panpsychism and the metaphysical possibility of a veridical interpretation of psychedelic states, and that this conceptual congruence has important implications for research on spiritual flourishing. This flourishing need not be understood in a theological manner, although it is, I suggest, entirely consistent with at least some naturalistic theological frameworks: the main goal of the article is to map the conceptual terrain in which conversations about spiritual flourishing, psychedelics, and panpsychism might take place.

Nomothetic Explanation and Humeanism about Laws of Nature

Humeanism about laws of nature—the view that the laws reduce to the Humean mosaic—is a popular view, but currently existing versions face powerful objections. The non-supervenience objection, the non-fundamentality objection, and the explanatory circularity objection have all been thought to cause problems for Humeanism. However, these objections share a guiding thought—they are all based on the idea that there is a certain kind of divergence between the practice of science and the metaphysical picture suggested by Humeanism. I suggest that the Humean should respond to these objections not by rejecting this divergence, but by arguing that it is appropriate. The Humean should distinguish between scientific and metaphysical explanation. And they should leverage this into distinctions between scientific and metaphysical fundamentality and scientific and metaphysical possibility. We can use these distinctions to respond to the objections that the Humean faces.

How to Be a Relationalist

Relationalism in metaphysics leads to indeterminism and non-locality in physics. This is widely thought to be a problem for relationalism, but here I argue that it is in fact a?virtue. More specifically, I distinguish two senses in which a physical theory can be indeterministic and non-local. Relationalism does imply indeterminism and non-locality in one sense, but this is a virtue since indeterminism and non-locality in this sense is precisely what empirical observation confirms. There is a second sense of the terms on which indeterminism and non-locality would be a problem, but I argue that relationalism does not imply indeterminism or non-locality in that sense. With respect to indeterminism and non-locality, then, relationalism gets things exactly right. This defense of relationalism rests on distinguishing these two senses of indeterminism and non-locality. Since both terms are intimately connected to metaphysical possibility, this requires distinguishing two species of the latter. The distinction between two senses of metaphysical possibility I offer may be of interest to metaphysicians regardless of its bearing on relationalism, determinism, and locality.

Foreword

This chapter is divided into four parts, corresponding to the partitioning of the essays in the volume. Part I, on neo-Fregeanism in the philosophy of mathematics develops replies to Demopolous, Heck, Rosen and Yablo, Boolos and Edwards; Part II, on vagueness, intuitionistic logic and the Sorites Paradox develops replies to Rumfitt and Schiffer; Part III, on revisionism in the philosophy of logic develops replies to Shieh and Tennant; and Part IV, on the epistemology of metaphysical possibility develops a reply to Hale. In each section, Crispin Wright offers an overview of the relevant area and outlines and refines his views on the relevant topics. Inter alia, he offers detailed replies to each of the ten contributed essays in the volume.