Qichen Yan

Teitel (Mind 128:39-68, 2019) argues that the following three doctrines are jointly inconsistent: i) the doctrine that metaphysical necessity reduces to essence; ii) the doctrine that possibly something could fail to exist; and iii) the doctrine that metaphysical necessity obeys a modal logic of at least S4. This paper presents a novel solution to Teitel’s puzzle, regimented in a higher-order logical setting, which is crucially based on the idea that the putative reduction of metaphysical necessity to essence should be understood through appealing to some hyperintensional notion—such as grounding or real definition—rather than the notion of identity/identification. Moreover, it will also be shown that the proposed reductive account has a significant advantage over its rival account.

Many philosophers hold that free will consists in the exercise of an agent's irreducible causal powers. However, it is controversial whether a powers-based approach to free will is compatible with determinism or not. In two papers published in this journal, Mumford and Anjum (2014) and Conti (2025) offer opposite answers to this question: Mumford and Anjum argue that a powers-based theory of free will implies incompatibilism, whereas Conti argues that it implies compatibilism. In this article, I defend Mumford and Anjum's view against Conti's objections. My argument will be based on some crucial clarifications regarding the definition of determinism.

Many philosophers, while maintaining that special relativity is a serious problem for the A-theory of time, deny that Newtonian physics (by itself) poses any serious challenge to the A-theory. This paper aims to show that this common view is false. I will argue that Newtonian physics and special relativity indeed pose the same sort of challenges to the A-theory, which can in principle be resolved by Newtonian A-theorists and relativistic A-theorists in the same manner. Hence, there is nothing essentially special about special relativity: if there is good reason to endorse the A-theory in a Newtonian world, then there is equally good reason to endorse the A-theory in a relativistic world.

The actualism/possibilism debate in ethics concerns the relationship between what we ought to do now and what we will freely do in the future. This paper presents a novel account of moral obligation which can effectively settle this debate. The proposed account has the following theoretical virtues: (i) it captures our actualist intuition that we are sometimes obligated not to do the best that we can; (ii) it captures our possibilist intuition that we are in some sense always obligated to do the best that we can (and can be blameworthy for failing to do the best that we can); (iii) it never prescribes practically incompatible moral obligations; (iv) it posits only one kind of moral obligation (so it is not a hybrid account). The drawback of the proposed account is, however, that it requires us to adopt a non-standard formulation of the ‘ought implies can’ principle (OIC), according to which one's being obligated to ϕ does not imply that one is able to ϕ, but rather that one could have been able to ϕ. Although this is a relatively revisionary move, independent motivations for preferring this modified formulation of OIC over its standard formulation will be provided.

In a recent paper in this journal, Maia offers an argument against the claim that the existence of circular sets in some non-well-founded set theories provides evidence that ontological dependence is neither irreflexive nor anti-symmetric. Maia’s argument is crucially based on the idea that there is an epistemic parity between two principles of set-dependence. In this paper, I show that Maia’s argument is flawed: the two principles of set-dependence that Maia proposes should not be treated on a par.

Alexander Roberts (2024) recently argues that, given some plausible auxiliary assumptions, anti-haecceitism, the thesis that necessarily every truth is necessitated by the qualitative truths, logically implies the identity of indiscernibles – the thesis that necessarily any qualitatively indiscernible individuals are the same. Roberts suggests that this observation might pose a challenge to anti-haecceitists who are convinced by Black’s (1952) famous example of a symmetric universe, which contains nothing but two duplicate iron spheres. In this paper, I argue that anti-haecceitists do have room to manoeuvre to get around this problem. The proposed response will be based on an important distinction between two different interpretations of physicalism.

Recently, there has been a lively debate over whether absolute velocity is measurable in Newtonian mechanics. Middleton and Murgueitio Ramírez (Australas J Philos 99(4): 806–816, 2021)—‘MMR’ henceforth—challenge the orthodox view that absolute velocity is unmeasurable in Newtonian mechanics by pointing out that, under a plausible counterfactual analysis of measurement, absolute velocity is measurable in at least one Newtonian world. MMR’s arguments have been criticized by Jacobs (Australas J Philos 100(1): 202–206, 2022) and Luc (Erkenntnis 89: 3309–3327, 2024), with Murgueitio Ramírez (Philos Compass 19(6), 2024) subsequently responding to both objections. In this paper, I present a novel response to MMR’s original argument that avoids the problems faced by Jacobs’s and Luc’s accounts. I argue that MMR’s reply to another potential objection to their account, which they call ‘the relevance objection’, is unconvincing. Building on a crucial clarification about this objection, I propose a revised counterfactual account of measurement, under which absolute velocity remains to be unmeasurable in Newtonian mechanics.

Teitel (Mind 128:39-68, 2019) argues that the following three doctrines are jointly inconsistent: i) the doctrine that metaphysical necessity reduces to essence; ii) the doctrine that possibly something could fail to exist; and iii) the doctrine that metaphysical necessity obeys a modal logic of at least S4. This paper presents a novel solution to Teitel’s puzzle, regimented in a higher-order logical setting, which is crucially based on the idea that the putative reduction of metaphysical necessity to essence should be understood through appealing to some hyperintensional notion—such as grounding or real definition—rather than the notion of identity/identification. Moreover, it will also be shown that the proposed reductive account has a significant advantage over its rival account.