Online research in philosophy

In this paper I aim to show that a certain law of nature, namely that common salt (sodium chloride) dissolves in water, is metaphysically necessary. The importance of this result is that it conflicts with a widely shared intuition that the laws of nature (most if not all) are contingent. There have been debates over whether some laws, such as Newton’s second law, might be definitional of their key terms and hence necessary. But the law that salt dissolves in water is not that kind of law. The law statement ‘salt dissolves in water’ is clearly synthetic. It appears a classic case of a contingent law. We like to believe that there are possible worlds in which the laws of nature are different and in which salt does not dissolve in water.

This paper challenges the Kripkean interpretation of a posteriori necessities. It will be demonstrated, by an analysis of classic examples, that the modal content of supposed a posteriori necessities is more complicated than the Kripkean line suggests. We will see that further research is needed concerning the a priori principles underlying all a posteriori necessities. In the course of this analysis it will emerge that the modal content of a posteriori necessities can be best described in terms of a Finean conception of modality – by giving essences priority over modality. The upshot of this is that we might be able to establish the necessity of certain supposed a posteriori necessities by a priori means.

In this paper I argue that it is not a priori that all the laws of nature are contingent. I assume that the fundamental laws are contingent and show that some non-trivial, a posteriori, non-basic laws may nonetheless be necessary in the sense of having no counterinstances in any possible world. I consider a law LS (such as 'salt dissolves in water') that concerns a substance S. Kripke's arguments concerning constitution show that the existence of S requires that a certain deeper level law or variants thereof hold. At the same time, that law and its variants may each entail the truth of LS. Thus the existence of S entails LS. Consequently there is no world in which S exists and fails to obey LS. I consider the conditions concerning the fundamental laws that would make this phenomenon ubiquitous. I conclude with some consequences for metaphysics.

A leaf falls to the ground, wafting lazily on the afternoon breeze. Clouds move across the sky, and birds sing. Are these events governed by universal laws of nature, laws that apply everywhere without exception, subsuming events such as the falling of the leaf, the movement of the clouds and the singing of the birds? Are such laws part of a small set of fundamental laws, or descended from such a set, which govern everything there is in the world?

When the atomic theory was revived in the seventeenth century, the atomists faced a problem concerning the status of the laws of nature. On the face of it, the postulation of absolutely hard, rigid, and impenetrable atoms seems to entail the existence of natural necessities and impossibilities: Atoms A and B cannot interpenetrate, so atom A must push atom B when they collide. The properties of compound bodies are to be explained in terms of their “textures” (i.e., the arrangements of their constituent atoms) on the famous lock-and-key model. Once again, it looks as if we have a domain of natural necessities depending on the textures of compound bodies. But the atomists seem to think of the laws of nature as radically contingent, not the sorts of things that could in principle be known a priori. This article seeks to address this tension between what the atomists seem committed to by their matter theory (real necessary connections in nature) and what they in fact say (that all the laws are contingent). In my Atomism (1995) I sought to resolve the tension by appealing to a sharp distinction between the atomists’ metaphysics and their epistemology. On this interpretation, they remain committed to natural necessity, but insist that we can never do Natural Philosophy in the “high priori” manner, by discovering real essences and their necessary connections. Our sciences of nature must remain empirical. Since publication of Atomism, however, this possible solution of the problem has come to seem more doubtful. Reflection on the work of my three “dissenting voices” (Margaret Osler, Peter Anstey and Rae Langton) has forced a radical rethink, focussing on the problematic relation between the intrinsic properties of the atoms and their (dynamic) powers. If there is no discoverable intelligible connection between what the atom is in itself (its intrinsic properties) and what it does (its powers), then my earlier solution will turn out to be untenable.

Introduction: Structural realism -- Necessities : earned truth and made truth -- Real impossibility -- What might have been -- Truth -- Perception and abstraction -- Emergent consciousness and irreducible understanding -- Real natures : software everywhere -- Going wrong with the master of falsity.

This paper sketches a dispositionalist conception of laws and shows how the dispositionalist should respond to certain objections. The view that properties are essentially dispositional is able to provide an account of laws that avoids the problems that face the two views of laws (the regularity and the contingent nomic necessitation views) that regard properties as categorical and laws as contingent. I discuss and reject the objections that (i) this view makes laws necessary whereas they are contingent; (ii) this view cannot account for certain kinds of laws of nature and their properties.

Laws of nature are puzzling because they have a 'modal character'—they seem to be 'necessary-ish'—even though they also seem to be metaphysically contingent. And it is hard to understand how contingent truths could have such a modal character. Scientific essentialism is a doctrine that seems to dissolve this puzzle, by showing that laws of nature are actually metaphysically necessary. I argue that even if the metaphysics of natural kinds and properties offered by scientific essentialism is correct, there are still some metaphysically contingent truths that share the modal character of the laws of nature. I argue that these contingent truths should be considered laws of nature. So even if scientific essentialism is true, at least some laws of nature are metaphysically contingent.

Is the relation between properties and the causal powers they confer necessary, or contingent? Necessary, says Sydney Shoemaker, on pain of skepticism about the properties. Contingent, says David Lewis, swallowing the skeptical conclusion. I shall argue that Lewis is right about the metaphysics, but that Shoemaker and Lewis are wrong about the epistemology. Properties have intrinsic natures (quiddities), which we can know.