HAVE THE LAWS OF NATURE BEEN ELIMINATED? TRAVIS DUMSDAY Are there really such things as laws of nature? In everyday parlance, such a question is liable to seem absurd; after all, is not a belief in laws the very foundation of modern science? Yet, when one delves into the question more deeply, it comes to appear less absurd, for one of the major ongoing debates in contemporary philosophy of science has to do with the ontology of laws: just what is it to be a law of nature? Depending on the answer one gives to this question, the idea that laws do not really exist may come to seem plausible. While such a position has had other defenders, notably Ronald Giere/ the most thoroughly developed and compelling case for it is to be found in Stephen Mumford's Laws in Nature. 2 There, he argues that laws of nature, properly understood as governing principles which explain regul­ arities, do not exist. Despite a number of valiant attempts by meta­ physicians to present a theory of laws that would explain what they are and how they exercise a causal force in the world, no convincing account has been forthcoming. What is more, a compelling alternative explanation for regularities has been set forth, namely that they result from the dispositions3 of objects. Whatever phenomena scientists employ laws to explain can instead be accounted for by reference to these, and consequently we have no reason to introduce law-talk into metaphysical discourse in the first place. In what follows, I will begin by providing a summary of Mumford's case against laws. I will then briefly review Alexander Bird's reply to 1 See Ronald Giere, Science Without Laws (Chicago: University of Chicago Press, 1999). 2 See Stephen Mumford, Laws in Nature (New York: Routledge, 2004). 3 I will here take "disposition," "causal power," "potentiality," and "capacity," as synonyms. This accords with common usage in recent analytic metaphysics, although in earlier literature distinctions were sometimes made between them, with "disposition" being applied specifically to mental capacities. 111 112 TRAVIS DUMSDA Y Mumford,4 where he argues that one can be both a dispositionalist and a nomological realist. I will argue that Bird's account of laws does not meet Mumford's criteria for lawhood, and that only two accounts can: one which takes laws as ontological primitives, or one which looks to theism to ground them. Between these two, I believe the theistic option is to be preferred, which has the interesting implications that if Mumford's criteria for lawhood are correct, and laws are real, then it is likely that God exists; and conversely, to be consistent, an atheist should either reject Mumford's criteria of lawhood in favor of a different conception of law, or accept his eliminativism. Thus, beliefs about God have a decided impact on the acceptability of certain conceptions of law. I. LAWS IN THE DOCK: MUMFORD'S CASE FOR ELIMINATION5 To begin, Mumford makes it clear that in his treatment of laws he is only concerned with those theories which postulate real laws of nature. On his view, it is essential to the notion of a law of nature that it be a truth, fact, or thing which somehow accounts for a regularity in nature. A law has an explanatory function: it governs actual occurrences.6 Thus, several theories commonly presented as theories of law are not really such. Hume's regularity theory is one instance of this, as he maintains that laws are simply regularities, such that what we call a "law" is just a record of what actually does happen in nature, when those happenings are sufficiently consistent to admit of grouping into a convenient class.7 Nothing modal is implied, no form of necessity invoked. Laws are not something over and above the occurrences of nature, nor have they any governing function; they just are the occurrences of nature, and 4 See his contribution to Alexander Bird, Brian Ellis, Stephen Mumford, and Stathis Psillos, "Looking for Laws," Metasdence 15 (2006): 437-69. 5 Note that this section is meant for those readers with little or no familiarity with Mumford's work; as such, I have tried to be as thorough as possible, within space constraints. Those who already have a good grasp of this material might wish to skip ahead to the next section. 6 Mumford, Laws in Nature, 1-3. 7 See Dav~d Hume, An Enquiry Concerning Human Understanding, in Enquiries Concerning. Human Understanding and Concerning the Principles of Morals, edited by L.A. Selby-Bigge (Oxford: Clarendon Press, 1975). HAVE THE LAWS OF NATURE BEEN ELIMINATED 113 would be different if the occurrences were different. David Lewis' theory that laws are systematizations of the world's historl is similarly not really a theory of law. Such accounts do not posit anything real in nature that accounts for regularities. Regularities exist, but with no explanans there to render them in any way necessary. Humeans et alia may of course choose to maintain the terminology of laws and refer to their theories as theories of law, but that will just result in a lack of terminological clarity. Nomenclature aside, the real metaphysical question Mumford wishes to confront is "whether there are any universal governing or controlling features in nature, features which, in some original sense of law, could be described as laws."9 Moreover, considered as an ontology in and of itself, regularity theory, whether Humean or Lewisean, leaves a gaping hole in the intelligibility of the natural world. To think that the pervasive regularities of the universe 8 See David Lewis, Counterfactuals (Oxford: Blackwell, 1973). 9 Mumford, Laws in Nature, 10. Foster's views here are similar. He also provides a helpful and concise set of distinctions: "The term 'law', as it occurs in the context of a discussion of the natural world, can be used in three distinct, though related, senses. In the first place, it can be used to refer to those claims by which, at various times, scientists have tried to characterize the fundamental ways of working of the natural world .... Taken in this sense, laws are not part of nature, but part of our theorizing about it. They are human artifacts, products of the scientific enterprise. Secondly, the term 'law' can be used to refer, not to these scientific claims, but to the natural regularities-the uniform ways of working-which the claims are attempts to record .... Thirdly, the term 'law' can, as in the second case, be used to denote aspects of the natural world, but aspects that consist not in the regularities which characterize the world, but in the forms of natural necessity which (in a certain sense) control it.. .. So, in this sense, to recognize a law of gravity would not be merely to recognize that there is a uniform manner in which bodies attract one another, but to recognize a principle of necessity underlying this uniformity .... Now it is in the third of these senses that I am using the term 'law' in these lectures" (John Foster, The Divine Lawmaker: Lectures on Induction, Laws of Nature, and the Existence of God [Oxford: Oxford University Press, 2004], 37-38). Clearly, his third use is close to Mumford's view of the proper understanding of a law of nature, although Foster is more willing to grant that the alternative uses of the term are also valid and related to the one he primarily wishes to consider. 114 TRAVIS DUMSDA Y lack any grounding whatever, that they are mere coincidences, while logically possible, strains credulity.10 Rather different concerns apply to Armstrong's much-discussed theory of laws as relations between universals. He developed it simultaneously with Dretske and Tooley, and so it is often referred to as the Dretske-Tooley-Armstrong (DTA) theory.11 However, the three theories are not equivalent in all respects, and Mumford's critique is directed primarily against Armstrong. This theory, very briefly, runs as follows: we normally think of relations as obtaining among particulars (one box being to the left of another, one person being taller than another, etc.), but, according to DTA advocates, relations can also obtain among universals, and one type of relation that can so obtain is that of nomic (law-like) necessitation. Two universals, F and G, can be linked together via the nomic necessitation relation N. This results in a law of nature, which takes the form N(F,G), or "it is a law that F's are G's." For instance, that water freezes at 0 degrees centigrade, ceteris paribus, is a relation of nomic necessitation between the universals "water" and "freezing at 0 degrees." Thus, it is a law that if the universal "water" is applied to an object, the universal "freezes when subjected to a temperature of 0 degrees Celsius under normal conditions" will likewise be applicable, due to the necessitation relation obtaining between the relevant universals. Armstrong, in his original formulation of the theory, also sought to retain what he takes as an intuition that the laws of nature are not absolutely necessary; that is, that there is some possible world in which the universals F and G are not linked by N. There are possible worlds in which water does not freeze at all, or does so only under very different conditions. The fact that these universals are linked in our world is contingent. Thus, we have a law when we have a contingent, external relation of nomic necessitation between instantiated universals. 10 This has been argued by a number of authors over the years.