People are quite fond of the best systems account of laws of nature. From a certain vantage point, it’s not hard to see why: it offers an intuitive picture of laws that avoids appeal to any spooky metaphysical gizmos like universals, and it dovetails neatly with Humean analyses of other related notions. Given these motivations, however, one might be troubled by the fact that the canonical formulation of the account (given by David Lewis [1973], [1983], [1986], [1994]) does not seem to marry up particularly well with what we see scientists doing with laws in the course of their inquiries. As just one example, it is far from clear that in evaluating candidate laws, scientists prize anything like the balance of strength and simplicity that the traditional best systems account uses to decide which system is the ‘best’.1
Enter pragmatic Humeanism. Under this banner, a series of philosophers have recently been attempting to reform the best systems account so that it can provide a plausible picture of how laws are used in scientific practice while retaining the account’s theoretical virtues. The guiding idea is that we might replace the traditional criteria for picking out the best system with ones that more closely reflect the role that laws play in scientific practice. The hope, then, is that we will find ourselves with an account that not only correctly identifies the laws that feature in scientific practice as laws, but that also makes sense of why, being laws, they can play the role that they do in scientific inquiry.
In their volume Humean Laws for Human Agents, Michael Townsen Hicks, Siegfried Jaag, and Christian Loew have collected a series of chapters that variously aim to strengthen, develop, criticize, and extend this pragmatic Humean programme. More specifically, the chapters in this volume fall into one of four rough categories:
(1) those that seek to strengthen, defend, clarify, and/or develop various pragmatic Humean accounts of laws;
(2) those that raise specific problems or challenges for pragmatic Humean accounts;
(3) those that develop alternatives to pragmatic Humeanism that nonetheless retain central elements of the pragmatic Humean views;
(4) those that leverage pragmatic considerations to tackle various problems for Humean views more broadly.
I’ll say a little bit about the chapters that fall within each of these categories in turn.
In this first category, Wolfgang Schwarz (chapter 3) argues that non-Humean accounts must deal with the serious problem of how we come to know about natural modality. He calls this the ‘access problem’: if the world contains primitive modal elements, how would we know about them? Schwarz examines and rejects a few ways that non-Humeans might go about solving this access problem: (i) appealing to a ‘thin’ conception of knowledge, (ii) taking certain epistemic norms to be in some sense primitive, and (iii) drawing a distinction between primitive ideology and primitive ontology. Given that none of these avenues looks particularly promising, Schwarz concludes that we should prefer pragmatic Humean accounts of natural modality.
Barry Loewer (chapter 6) outlines how it seems to him that his preferred version of pragmatic Humeanism, the package deal account, is able to overcome two important criticisms of Humean views. According to the package deal account, both laws and fundamental properties are determined as a joint package according to the criteria that scientists employ in choosing between various theories. The package deal account, Loewer argues, can help Humeans to avoid the accusation of explanatory circularity with which they are often presented—that on Humean views, laws are supposed to both explain and be explained by their instances. Since laws and properties come as a package, we don’t need to think that laws are explained by their instances. In addition, Loewer argues that the objection that Humeanism makes the order we observe in the world seem astoundingly unlikely rests on the assumption that the properties of a world are prior to the laws. Since the package deal account places laws and properties on the same footing, it may fare better in addressing this kind of objection.
Markus Schrenk (chapter 8) applies a variety of pragmatic consideration to the question of so-called special science laws. According to the better best system account (originally developed by Cohen and Callender [2009]), different sciences can appeal to their own assemblage of properties, rather than being confined to employing the ‘fundamental’ ones unearthed in some particular corner of physics. Schrenk puts forward a new way of thinking about these various best systems, aimed at dealing with a series of related challenges that proponents of the better best systems account might face. By and large, these challenges relate to whether the broader picture of science that emerges seems too anthropocentric, or too much like a series of disconnected patchworks, or too wedded to particular sets of properties.
Chris Dorst (chapter 9) builds on his own best predictive system account, according to which laws are determined by the systematization of the Humean mosaic that is most predictively useful, in order to deal with a series of objections to pragmatic Humean accounts. The challenge is this: if the fact that laws are in many ways predictively useful to us should be considered to be evidence in favour of something like the best predictive system account, do the ways that laws fail to be predictively useful undermine such views? Dorst considers a variety of such failures, including questions about quantum indeterminacy and causal histories in special relativity. In response, Dorst splits the difference between accommodating some of these cases in the framework of his pragmatic Humean view and reflecting on the kinds of conceptual developments in science that lead to laws and predictions in the first place.
The series of chapters that pose explicit challenges to pragmatic Humean accounts begins with one by Alison Fernandes (chapter 4), in which she suggests that Humean views do not perform quite as well as they are claimed to when it comes to making sense of the explanatory role of chance in scientific inquiry. She argues that the story that Humeans offer as to why agents should align their credences with what they believe to be the chances relies on a species of indifference principle. The a priori nature of this kind of indifference reasoning is in tension with the avowedly naturalistic motivation claimed by many Humean views in the first place. Moreover, the resulting story furnishes us with a metaphysical guarantee of the alignment between chances and frequencies that places the view further out of step with scientific practice. Fernandes concludes that the Humean cannot deliver the naturalistically motivated account of chance they have been promising all along.
In their contribution, Heather Demarest and Elizabeth Miller (chapter 5) are concerned primarily with a kind of undermining problem. At the heart of the problem is the fact that, on Humean views, facts about laws depend on facts about quite global patterns. Demarest and Miller suggest that since non-fundamental properties exist by virtue of the patterns in which they feature, in worlds with different laws we may not be able to find the same non-fundamental properties. But if this is the case, then how can we use the laws to make sense of counterfactual claims, when the properties that they refer to may not even exist in other possible worlds? This undermining problem threatens the neat story about the relationship between laws, modality, and counterfactuals that many Humeans have put forward as a virtue of their view.
Harjit Bhogal (chapter 7) focuses on whether the package deal account elaborated by Loewer furnishes us with a notion of naturalness that can play the kinds of roles that Humeans imagine it might. He identifies three such roles: a metaphysical role in characterizing the mosaic, a role in identifying the data about which our theories must be informative, and a role in fixing the language in which the axioms of the system can be formulated. Bhogal suggests that it is difficult to see how the package deal account can provide us with a notion of naturalness that can play these roles unless we emphasize the fact that it is a kind of ideal observer view. The problem here, however, is that this obscures the connections between scientific practice and our account of laws that was supposed to make the package deal account attractive in the first place. Bhogal suggests that what we make of such problems may well depend on what we want the package deal account to achieve for us in the first place.
The chapter by Jenann Ismael (chapter 2) is the first in the volume that develops a substantial alternative to a pragmatic Humean view, motivated nonetheless by allied pragmatic considerations. Ismael argues that the Humean is not able to provide an epistemology that works for limited, embedded agents. If free recombination is possible and our universe is indefinitely extendible, then a Humean agent will not be able to confirm any hypotheses about laws and chances by observing only a finite portion of the mosaic. Ismael’s response is to let go of recombination; by the lights of the Humean’s motivation in the first place, she suggests, it represents a kind of metaphysical overreach. The view she arrives at is therefore decidedly non-Humean, but nonetheless shares many of its pragmatic sympathies—she considers the labels ‘anti-neo-Humean’ or ‘neo-anti-Humean’.
John Roberts (chapter 11) makes use of a different kind of pragmatic component to put together the first steps for a Humean theories of laws, counterfactuals, and causation in one fell swoop. This theory is built around the notion of an effective method. In general, methods consist of a means, enabling conditions, and an end. The effective methods are picked out in a somewhat Peircean fashion as the ones that in the limit of scientific inquiry would be judged to be effective. Roberts then sets out to recover an analysis of all of the other natural modalities in terms of this notion of an effective method.
Finally, there remains the category of chapters that tackle broader problems for Humean views by way of various pragmatic considerations. Craig Callender (chapter 1) makes use of a very interesting meta-ethical analogy to place the development of Humean views of laws in a wider context. In response to a variety of problems, proponents of ideal observer theories in meta-ethics began to understand their accounts instead as involving an ideal advisor. Callender thinks that Humean views could benefit from a similar shift of perspective. One upshot of this is that the Humean view is pushed quite close to some species of projectivism about laws. This, Callender concludes, is no problem at all—the systems approach and projectivist theories are, he suggests, in some sense climbing two sides of the same mountain and may ultimately complement each other.
In his contribution, Thomas Blanchard (chapter 10) argues that there are aspects of scientific practice surrounding laws that we cannot make sense of by simply appealing to their predictive utility. What the pragmatic Humean framework is missing, Blanchard suggests, is that scientists require laws to be maximally explanatory principles. The question here is: what notion of explanation are we to employ? Given the Humean focus on systematization, unificationist notions of understanding seem a natural fit. To this end, Blanchard puts together just such a unificationist account of explanation, allowing him to articulate the details of a new, explanation-focused version of the best systems account.
Finally, Ned Hall (chapter 12) takes inspiration from how pragmatic Humeans approached the task of developing a reductionist account of laws in order to develop a Humean reductionist account of essence. There are, he suggests, two different ways that we can go about explaining the importance of certain kinds of generalizations that appear to appeal to the essence of certain objects: a metaphysical account and an epistemic-utility account. Following the approach of pragmatic Humean accounts of laws, Hall suggests that the epistemic approach allows us to think about how certain kinds of generalizations facilitate inquiry in ways that others do not. This, he concludes, allows us to understand what kind of work we might need a notion of essence to do in various theoretical contexts and to solve some puzzles by which we might be plagued if we insist on a more thoroughly metaphysical approach.
Altogether, the chapters that make up this volume present the reader with a detailed picture of the various directions that the broadly pragmatic Humean programme might be heading when it comes to questions about laws, chances, and some other related notions. As a minor point: This picture may have, at least for me, come into view slightly more sharply if more attention were given to some of the methodological underpinnings of this programme. For instance, almost all of the chapters feature a variety of appeals to scientific practice, but it is not always exactly clear what, if anything, strings these various appeals together. It is, by and large, taken for granted that facts about scientific practice will automatically be relevant to the metaphysical questions in which Humeans are interested. Of course, this is in some way the outlook that characterizes the pragmatic strand of Humeanism with which the volume is concerned, but I nonetheless found myself wondering quite regularly how exactly these authors were conceiving of the relationship between metaphysical questions about laws and chances, on the one hand, and questions about the complex and messy details of scientific methodology, on the other hand.
That said, I think this is a tremendous volume, containing some rich and outstanding chapters. It showcases the range of perspectives and approaches that can flourish even within a broadly pragmatic Humean programme, and will certainly be of interest to anyone working on laws—metaphysicians and philosophers of science alike.
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Elizabeth Hannon2024-11-05 07:00:492024-10-21 15:52:33Marshall Abrams, Evolution and the Machinery of Chance // Reviewed by Charles H Pence
