Online research in philosophy

The standard view of metaphysical necessity is that it is truth in all possible worlds, and therefore that the correct modal logic for metaphysical necessity is S5, in models of which all worlds are accessible from each other. I argue that S5 cannot be the correct logic for metaphysical necessity because accessibility is not symmetric: there are possible worlds that are accessible from ours but from which our world is not accessible. There are (or could be) some individuals who, if they had not existed, could not have existed. Once the possibility of such individuals is lost, it is gone forever.

The striking difference between the orthodox nomological necessitation view of laws and the claims made recently by Scientific Essentialism is that on the latter interpretation laws are metaphysically necessary while they are contingent on the basis of the former. This shift is usually perceived as an upgrading: essentialism makes the laws as robust as possible. The aim of my paper—in which I contrast Brian Ellis’s Scientific Essentialism and David Armstrong’s theory of nomological necessity—is threefold. (1) I first underline the familiar fact that metaphysical necessity (of Kripkean “water is necessarily H2O” kind) is not a stronger kind of necessity than nomological necessity but an entirely different kind of thing: nomological, but not metaphysical necessity, is an intra-world necessitation which Armstrong (almost) identifies with causation; metaphysical, but not nomological necessitation, has a canonical link to possible world considerations and counterfactual reasoning. Hence, the change from one necessity to the other is not an upgrading but a substantial shift. (2) I will explain how the essentialists, who promote this shift, are nonetheless able to retain the features of nomological necessity. (3) I also explore, for both the essentialist and the Armstrongian, whether they could extract a modal force from intra-world nomological necessity which it does not have per se. I argue that such a modal force is, indeed, obtainable for them. I will close the paper with some remarks and questions about the relation between Kripkean metaphysical necessity and the modal version of nomological necessity as defined in (3).

It is commonly accepted by Kant scholars that Kant held that all necessary truths are a priori, and all a priori knowledge is knowledge of necessary truths. Against the prevailing interpretation, I argue that Kant was agnostic as to whether necessity and a priority are co-extensive. I focus on three kinds of modality Kant implicitly distinguishes: formal possibility and necessity, empirical possibility and necessity, and noumenal possibility and necessity. Formal possibility is compatibility with the forms of experience; empirical possibility is compatibility with the causal powers of empirical objects; noumenal possibility is compatibility with the causal powers of things in themselves. Because we cannot know the causal powers of things in themselves, we cannot know what is noumenally necessary and what is noumenally contingent. Consequently, we cannot know whether noumenal necessity is co-extensive with a priority. Therefore, for all we know, some a priori propositions are noumenally contingent, and some a posteriori propositions are noumenally necessary. Thus, contrary to the received interpretation, Kant distinguishes epistemological from metaphysical modality.

Hume's arguments for the contention that causal necessity precludes logical necessity depend on the questionable principle that a cause must precede its effect. Hobbes' definition of entire cause, although it fails to account for causal priority, is not refuted by Hume. The objections of Myles Brand and Marshall Swain (Philosophical Studies, 1976) to my counterexample against Hume (Philosophical Studies, 1975) are ineffective. Their other objections to my criticisms of their argument against defining causation in terms of necessary and sufficient conditions (Synthese, 1970) are also mostly ineffective.

This article argues for two related theses. First, it defends a general thesis: any kind of necessity, including metaphysical necessity, can only be known a priori. Second, however, it also argues that the sort of a priori involved in modal metaphysical knowledge is not related to imagination or any sort of so-called epistemic possibility. Imagination is neither a proof of possibility nor a limit to necessity. Rather, modal metaphysical knowledge is built on intuition of philosophical categories and the structures they form.

I propose a different way of thinking about metaphysical and physical necessity: namely that the fundamental notion of necessity is what would ordinarily be called "truth in all physically possible worlds" – a notion which includes the standard physical necessities and the metaphysical ones as well; I suggest that the latter are marked off not as a stricter kind of necessity but by their epistemic status. One result of this reconceptualization is that the Descartes-Kripke argument against naturalism need no longer trouble us. I end by relating the difference between my view and the standard view to the question, whether there could have been a different world than ours.

Minimally, causal realism (as understood here) is the view that accounts of causation in terms of mere, regular or probabilistic conjunction are unsatisfactory, and that causal phenomena are correctly associated with some form of de re necessity. Classic arguments, however, some of which date back to Sextus Empiricus and have appeared many times since, including famously in Russell, suggest that the very notion of causal realism is incoherent. In this paper I argue that if such objections seem compelling, it is only because everyday expressions concerning causal phenomena are misleading with respect to certain metaphysical details. These expressions generally make reference to the relations of events or states of affairs, but ignore or obscure the role played by causal properties. I argue that on a proposed alternative, an analysis in terms of causal processes, more refined descriptions of causal phenomena escape the charge of incoherence. Causal necessity is here located in the relations of causal properties. I distinguish this view from the recent process theories of Salmon and Dowe, which are disinterested in causal realism.

A lot of philosophers engage in debates about what claims are “metaphysically necessary”, and a lot more assume with little argument that some classes of claims have the status of “metaphysical necessity”. I think we can usefully replace questions about metaphysical necessity with five other questions which each capture some of what people may have had in mind when talking about metaphysical necessity. This paper explains these five other questions, and then discusses the question “how much of metaphysics is metaphysically necessary?”, and each of its five replacements.

Causal necessity typically receives only oblique attention. Causal relations, laws of nature, counterfactual conditionals, or dispositions are usually the immediate subject(s) of interest. All of these, however, have a common feature. In some way, they involve the causal modality, some form of natural or physical necessity. In this paper, causal necessity is discussed with the purpose of determining whether a completely general empiricist theory can account for the causal in terms of the noncausal. Based on an examination of causal relations, laws of nature, counterfactual conditionals, and dispositions, it is argued that no reductive program devoid of essentialist commitments can account for all the phenomena that involve causal necessity. Hence, neo-Humean empiricism fails to provide a framework adequate for understanding causal necessity.

This paper concerns anti-Humean intuitions about connections in nature. It argues for the existence of a de re link that is not necessity.Some anti-Humeans tacitly assume that metaphysical necessity can be used for all sorts of anti-Humean desires. Metaphysical necessity is thought to stick together whatever would be loose and separate in a Hume world, as if it were a kind of universal superglue.I argue that this is not feasible. Metaphysical necessity might connect synchronically co-existent properties—kinds and their essential features, for example—but it is difficult to see how it could also serve as the binding force for successions of events. That is, metaphysical necessity seems not to be fit for diachronic, causal affairs in which causal laws, causation, or dispositions are involved. A different anti-Humean connection in nature has to do that job.My arguments focus mainly on a debate which has been the battleground for Humean vs. anti-Humean intuitions for many decades—namely, the analysis of dispositional predicates—yet I believe (but do not argue here) that the arguments generalise to causation and causal laws straightforwardly.