Theoretical Correlates and Laws

Recent literature concerning laws of nature highlights the close relationship between general metaphysics and philosophy of science. In particular, a person’s theoretical commitments in either area have direct implications for her stance on laws. For example, Dretske, Tooley, and Armstrong each independently developed an account of laws (henceforth, the DTA account) that

takes laws to be second-order relations among universals. Although each of them maintains a different account of universals and there are subtle, yet significant, distinctions between their accounts, it is by allowing universals in their ontology that permits their account of laws to involve such universals.

Whereas the DTA accounts of laws can be said to have Platonic origins, Bird develops an account of laws from within a neo-Aristotelian framework. His neo-Aristotelian sympathies lead him to endorse an ontology that includes dispositions, powers, and essences in addition to individual substances. His account of laws has two significant features resulting from this

ontology: 1) Laws are metaphysically necessary because 2) Laws are taken to supervene on those properties that essentially have their dispositions (Bird 2007, 204-205).

Not all nonreductive accounts of laws make use of either universals or dispositions.125 For example, Carroll maintains that without laws “there would be little else” (Carroll 1994, 3; emphasis in original). In particular, our understanding of causes, dispositions, counterfactuals, perception, and everyday objects is dependent upon our understanding of laws (Carroll 1994, 10). Rather than appealing to universals, Carroll understands laws in commonsense terms consonant with a Laplacean worldview (Carroll 1994, 160).126 Lange also does not make use of universals in his argument that laws of nature are to be grounded in primitive subjunctive facts— facts about what might occur in the world under counterfactual conditions (Lange 2009, ix). In both Carroll’s and Lange’s accounts, laws are appealed to for understanding other nomic

125 _{To say that a law of nature is nonreductive does not entail that the concept of lawhood is not analyzable, only that}

what it is to be a law is not reducible to the facts about the world the laws are said to govern.

concepts such as cause, chance, counterfactuals, and modality—without reducing laws to what is or has been the case or appealing to relations among universals or dispositions.

Although the previously mentioned accounts of laws do not reduce laws to descriptions or facts about what is or has been the case, there are other, more ontologically sparse accounts that seek to understand laws only in terms of such facts. These reductive accounts are often called Humean. Interestingly, Hume never provided an account of laws. To account for this homage Lewis famously states, “Humean Supervenience is named in honor of the great denier of necessary connections. It is the doctrine that all there is to the world is a vast mosaic of local matters of particular fact—just one little thing and then another” (Lewis 1986, ix). For present purposes, although I think it is an unfortunate label, it is not important whether or not Humean accounts are appropriately labeled as such; what is important is the Humean’s denial of

necessary connections.

The explicit rejection of necessary connections has served as a foundation for at least two reductive accounts of laws. First, Schaffer argues for an account in which causation is reducible to history and the laws of nature, and those laws are themselves reducible to history (Schaffer 2008, 82). History, on Schaffer’s view, is understood as being “the fusion of all events

throughout spacetime” (Schaffer 2008, 83). To say that the laws of nature are reducible to

history, then, is to argue that one should look no further than the “pattern of events.”127 This view provides a simple reductionist account that may be understood as a regularity view of laws. In particular, this treatment of laws understands them as being exceptionless regularities capable of generating “true universally quantified conditionals” (Schaffer 2008, 83).

127 _{This may also be understood in terms of a supervenience account, in which the laws are understood to supervene}

The second reductive (or supervenience) account is more nuanced than Schaffer’s. Often referred to as the Best System Analysis, the view has been developed by Mill (1973), Ramsey (1990), and Lewis (1973), and has been most recently advocated for by Beebee (2000). Lewis provides a clear summary of the account when he writes, “[A] contingent generalization is a law of nature if and only if it appears as a theorem (or axiom) in each of the true deductive systems that achieves a best combination of simplicity and strength” (Lewis 1973, 73). The denial of necessary connections indicates that the laws themselves neither determine the facts that will occur or are themselves necessary. Instead, the laws at a world are determined by the facts at that world. The theorems (or axioms) to be taken as candidate laws are those that we, or an idealized epistemic subject, would derive after having arranged all of the known facts in a deductive system. In keeping with the traditional appeal to laws for the purposes of providing explanations, the laws would include not only those theorems (or axioms) derived from the deductive system, but also those theorems (or axioms) capable of explaining the phenomena that are of interest to and potentially made intelligible by us. This has interesting implications for the metaphysics of laws. On this view, laws are determined by the structure of the deductive systems, which are dependent upon the contingent facts of the world that are used for the purposes of deriving the theorems (or stipulating the axioms) and are further determined by our cognitive limitations and pragmatic explanatory concerns.128

Despite the stark contrast between reductivists and nonreductivists, they both maintain realist commitments to laws. The ways in which they maintain such commitments, as I have discussed, indicate the account of laws that they endorse. Not everyone is a realist, though.                                                                                                                          

128 _{Although the majority of Humeans forego the idea that laws of nature govern, Roberts maintains an ontology}

Those who have developed antirealist and instrumentalist views have also made claims regarding the nature of laws. For example, Cartwright, an instrumentalist about science, recognizes that local laws may be understood realistically about a given phenomenon, but only insofar as they figure into scientific models (Cartwright 1983, 18). This is consistent with her patchwork view of laws that results from understanding the world through science, and, since the sciences are not unified, she argues that we should not maintain that there are general universal laws (Cartwright 1999).

Van Fraassen proposes an even less sympathetic view of laws resulting from his constructive empiricism, which maintains the perspective that “scientific activity is one of construction rather than discovery: construction of models that must be adequate to the phenomena, and not discovery of truth concerning the unobservable” (van Fraassen 1980, 5). Since laws, according to van Fraassen, do not contribute to scientific models, or any significant scientific activity for that matter, then we should dispense altogether with the idea that there are laws (van Fraassen 1989, 181-184).

The upshot of the above survey is to highlight how theoretical commitments in either metaphysics or philosophy of science have direct implications for what is taken to be an

acceptable account of laws. The positions I have considered are from either extreme of the realist / antirealist spectrum. Structural realism, as discussed in the previous chapter, is a position developed in response to the difficulties facing both realism and antirealism. Given the trend I identify above in understanding why a person holds some stance on laws and not others, it appears that the structural realist should also take a stance on the issue of laws. Structural

realists, however, have not (until very recently) begun to discuss the nature of laws.129 What it is for something to be a law for the structural realist remains unclear. For this reason, some account of what the structural realist should say about laws is called for.

The remainder of the chapter clarifies the ontic structural realist’s stance on laws. In particular, I illustrate how since the ontic structural realist is a realist about laws, in addition to maintaining realist stances on modal and causal relations, she will need to adopt a process framework. This discussion provides support for the more general claim that an ontic structural realist should adopt a process metaphysics.