Completing the landscape on models and scientific representation 

Roman Frigg: Models and theories: a philosophical inquiry. London:Routledge, 2022, 495 pp, 

Open access at: https://www.taylorfrancis.com/books/9781844654918

“What are theories? What are models? And how do models and theories relate to each other? These are the core questions that this book is concerned with” (1). These expansive questions predictably give rise to a monumental 500-page monograph that Roman Frigg presents as, at once, an introduction, a literature review, and a critical assessment (1). On all these tasks, the book works very well. Unlike standard textbooks, Frigg does not indulge in didactic simplification: he smoothly walks the reader from the elementary concepts to the upper echelons of the question under analysis.  Having been an active participant or direct witness of two decades of debates on the title topics, Frigg’s scholarship and insight are often extraordinary. And so is the organization of the material presented. In a time where books are often collected papers in disguise, here discussions are systematically developed through the book’s four parts until each of the running threads is exhausted. Yet, the number of cross-references and signposts makes it almost impossible for the reader to get lost.

Reviewing this book requires hard choices. I will mainly focus on the first two parts in which Frigg presents his original view of the old masters’ views in our discipline, from Carnap to Suppe, hoping it will be less known to the average reader than the content of parts three and four. In them, Frigg discusses the last forty years of work on models and scientific representation, completing the landscape that he had already presented in his previous volumes. 

The first part of the book introduces the Linguistic View of Theories: “a scientific theory is a description of its subject matter in a formal language” (5). Frigg’s first move is to separate the Linguistic from the traditional Received View (RV) to make his initial claim: the latter may have fallen, but the former lives on.  Both are based on three principles, and the first two are reasonably similar between the two views: 1) “The language in which the theory is formulated has a logical structure that allows scientists to derive propositions from other propositions and to formulate proofs of theorems,” and 2) “A theory contains general principles, or axioms, which are the theory’s laws” (18). The difference lies in the third principle: 3) whereas for the linguistic view, in the language of the theory there are pre-theoretical terms and technical terms that arise within the theory, in the Received View, the terms are either logical or extra-logical and the latter are further divided into theoretical and observational.

Frigg rehearses, in Chapter 1, some standard objections against the RV, showing that most of them are based “either on misattributions, misunderstandings, or on hasty conclusions” (25). The real problems for the linguistic view appear in the following three chapters, and they are addressed in an equally constructive way. In Chapter 2, Frigg presents the role of models in the RV as alternative interpretations of a theory’s formalism, i.e., as logical models without any representational role. A consequence of the denial that models play a representation role is that according to RV a theory is connected to the world only by the observation terms and correspondence rules. A persistent strand of argumentation is that the limiting results in first-order logic, notably Gödel’s first incompleteness theorem and the Löwenheim-Skolem theorem, show such an analysis to be untenable. But, Frigg observes, these arguments are not conclusive, and they would only be a problem if the RV was inextricably tied to first-order logic, a claim for which he finds no evidence.

The challenge discussed in Chapter 3 is whether the distinction between theoretical and observation terms is tenable, to what extent observations are theory-laden, and how the relation between observation and data should be understood. Frigg concludes that the distinction between observation terms and theoretical terms should be given up and replaced by a dichotomy between antecedently understood and new terms, where the latter might be analysed in terms of Balzer, Moulines and Sneed’s notion of the T-theoreticity. This leaves the question of how data models fit into a linguistic view of theories. According to Frigg, the linguistic view is not reductive in this regard: scientific data should not be reduced to sentences to understand their epistemic input on a theory, data models can also do the job. 

Chapter 4 is about the semantics of theoretical terms, and how to define them. Although the review of the alternatives under discussion is significantly longer than in any other chapter—starting with verificationism ending with the causal theory of reference—Frigg takes no sides here. “This is still an active field of research” (140) is the chapter’s bottom line. Probably he does not need to take sides: of the three principles defining the RV, he just needs the first two, pertaining to the logical structure of theories and the presence of axioms, to assert the viability of the Linguistic View.  

The next step is to show the compatibility of the Linguistic View with the Model-Theoretical View (MTV), in which a scientific theory is mainly a family of models. Frigg had already warned his readers, in the first part of the book, that his “liberal” version of the RV is “in fact indistinguishable from a liberal” MTV: for both, the analysis of theories should be formal; in the liberal RV a theory would be “a language with a family of models”; in the liberal MTV a theory would be a family of models with a language. Here is another foundational claim of the book: “The consensus then is that any reasonable analysis of a theory must be a dual view” (167). 

The second part shows how far this consensus goes. Chapters 5 to 7 deal with the mainstream version of the MTV, in which models are mathematical structures.  Chapter 5 presents Suppe’s foundational ideas, lists the main developments of this view, and considers how the MTV solves the problems discussed in Part 1. New problems, of course, appear—-e.g., do models constitute or represent a theory? Crucially, Frigg presents here his case for having language as a key ingredient of the MTV. 

In Chapter 6, he hammers this point in a thorough discussion of the representational role of models in the MTV, in which Frigg draws on his previous work on scientific representation to map the territory with several adequacy conditions and reference problems. Two contending approaches are considered: the Data Matching Account and the Morphism Account. In the former, “a model M is a scientific representation of target T iff a measurement performed on T yields data model D and D is isomorphic to M’s empirical substructure” (212).  Siding with Bogen and Woodward, Frigg quickly discards it, arguing that the theories represent phenomena, not data models. In the Morphism account, “M is a scientific representation of T iff M is isomorphic to T” (201). The first problem here is in specifying in what sense the objects in the target system are a structure isomorphic to a set-theoretic M. And then Frigg proceeds to show in detail how morphism accounts are ill-equipped to deal with some desiderata that any view of scientific representation should meet. 

Chapter 7 explores the links between models belonging to the same theory in the light of the Munich structuralist school, Balzer, Moulines, and Sneed. The distinctions introduced in this account to deal with the different models within a theory successfully illuminate problems like theory-ladeness. But the Munich school does not have a solution for the problems so far detected in other structuralist accounts.
Chapter 8 completes this second part examining Giere’s and Suppe’s non-structuralist accounts of the MTV. Although the key ingredients are now models conceived as abstract entities representing the world through similarities, these accounts equally fail to meet Frigg’s desiderata for scientific representation, for the same underlying reason: language also plays an essential, but unexamined role in these alternative versions of the MTV.  

We are now halfway through the book. The lesson that emerges clearly from the discussion is that “purist” versions of either the linguistic or the model theoretical view are untenable. As Frigg puts it in the Envoi: “Any tenable account will have to see theories as consisting of both linguistic and non-linguistic elements” (490). This means that a defensible analysis of theories must be a dual view. Frigg’s discussion at this point remains programmatic. He sketches the main outlines of a dual view, but he leaves the task of working out the details of such a view to future research.  

In the third and the fourth part, we are treated to an in-depth exploration of twenty-five more years of controversies on scientific representation. Unlike the previous two parts, there will be no unifying threads like the RV or the MTV: the focus is now on models in scientific practice, without any overarching program of rational reconstruction. 

Each chapter in Part 3 deals with open questions about how models represent. In Chapter 9, we find several contenders for the very notion of scientific representation: namely, direct representation, inferentialism, and representation-as approaches. The next three chapters present critical discussions of specific kinds of representation via models: analogy in Chapter 10, abstraction and approximation in Chapter 11, and idealisation in Chapter 12. Whereas Chapter 9 closes with an overview of Frigg’s own DEKI account (where the acronym stands for denotation, exemplification, keying up, and imputation), on which he has extensively published elsewhere, the other chapters in this third part are critical assessments of the state of the art in the respective subject areas.

In Part 4, the author really struggles not to be carried away by casuistry and find philosophical threads connecting an immense and disperse literature. The opening thirteenth chapter engages in a mostly case-based debate on the autonomy of models from theories. Frigg provides a reasonably representative sample of how this autonomy has been analysed in the models in scientific practice literature. We also find a very nice overview of the debate between some leading authors in this approach and their counterparts in the MTV on whether the latter’s account of models captures the diversity of scientific practice—Frigg doubts it. The three final chapters are also opinionated. In Chapter 14, discussing the ontology of models, Frigg sets some desiderata and defends his own Waltonian fictional account, in line with DEKI. Chapter 15 deals with some philosophical dilemmas arising from the proliferation of models, exploring, for example, how robustness analysis exploits it for good or how perspectivism makes sense of the variety. These are ongoing debates, and the challenges Frigg proposes for the latter view are, in my view, worth considering. The last chapter, Chapter 16, contains an original classification of model types that I will just quote, for the sake of brevity: “1) Model types pertaining to model-target relations; 2) Model types pertaining to carriers; 3) Model types pertaining to the process of model construction and to models’ relation to theory; 4) Model types pertaining to the uses and functions of models in the scientific process” (467–468).  

What is the moral that the reader should draw from this second half of the book? In the final “Envoi”, Frigg is at once short and ambitious: “The next step in a discussion of representation will be to get to a better understanding of particular representation relations and the styles to which they belong, as well as to integrate an account of how models represent into a broader understanding of the structure of theories” (490). In other words, merge the main threads of this book into a unified view. Frigg has masterfully laid out the foundations of this project for any newcomer in the discipline, like Suppe did with his own volume in the 1970s. We can only hope it will orient future debates with similar success.

{January, 2024} {Metascience}

The rule in the knowledge machine

Michael Strevens, The Knowledge Machine: How Irrationality Created Modern Science, Liveright, New York, 2020, 350 pp. hard-back, 30$

The Knowledge machine is a book about the Iron rule of explanation (IRE). According to Michael Strevens, science has worked because scientific communities have strictly played by this rule ever since Newton. In the author’s own words, this is:

The rule demanding that all scientific arguments be settled by empirical testing, along with the elaborations that give the demand its distinctive content: a definition of empirical testing in terms of shallow causal explanation, a definition of official scientific argument as opposed to informal or private reasoning, and the exclusion of all subjective considerations and nonempirical considerations (philosophical, religious, aesthetic) from official scientific argument. [293]

With the IRE Strevens wants to settle the Great Method debate, initiated by methodists like Popper and Kuhn and then dominated by radical subjectivism (now prevalent among historians and sociologists of science). According to Strevens, the former focused on the wrong rule, be it falsificationism or the organization of scientific paradigms. The latter deny that there is any correct rule,  scientific outcomes are just like any social agreement, a matter of taste, interests, power etc. Strevens accepts the role of all these factors in the dynamics of science, but condensed into plausibility rankings, “a scientist’s level of confidence that a hypothesis or other assumption is true” [293]. But subjectivity is then constrained by the IRE: the game of science is about scientists organizing empirical tournaments in which a winner emerges, independently of the conflicting interests or values of the participants. According to Strevens, the accumulation of evidence, in the long run, brings about consensus on the true theory, the one that explains all relevant observations.

The gist of the iron rule is to minimize scientific debate about things scientists may not easily agree on and motivate scientists to “squeeze every last drop of predictive power” from a scientific paradigm. For Strevens, playing by the IRE and only the IRE is irrational: the IRE “imposes a wholesale prohibition on all forms of nonempirical thinking, no matter their track record, no matter how well they synergize with empirical observations” [237]. A chapter on the fruitfulness of beauty as a guiding principle of science exemplifies this point. But the alternative (using some other guiding principles in addition to the IRE) is worse: scientists may never reach an agreement.

Strevens discusses the Thirty Years’ War to illustrate how making religion a private matter is the best strategy to avoid civil unrest, and modern science would have its foundation in this separation. The recipe is still valid today: Keep empirical tests separate from any other consideration and let these tests proceed until a consensus is reached, keepscience working like a well-oiled automaton (a knowledge machine), do not meddle with the IRE.

Although Strevens is famous for his dense prose and subtle conceptual analyses, The Knowledge Machine was conceived as a popular philosophy book, an a quite successful one at that –already with reviews in major international newspapers and magazines such The New Yorker. A reason for this lies in the long collection of snapshots in the History of science that illustrate the concepts presented above and make for a fun reading. Radical –and a few moderate- subjectivists will probably challenge the details of these abridged case studies, but this is a scholarly debate, for which Strevens will probably be ready –although the footnotes and references are rather sketchy so that it is often difficult to determine the depth of his knowledge of each particular case.

What was less clear to me though was the message this book is sending to the public. As Strevens acknowledges in the first half of the book, his predecessors in the Great Method Debate were all conveying an image of scientists that became hugely influential among the educated Westerners: the Popperian dissenter, the Kuhnian Cold warrior, the Latourian black-boxer. These images made plain sense against the background of the political dilemmas of their time, partly reconstructed by Strevens for his readers. However, about our own dilemmas, Strevens remains mostly silent and his final advice sounds almost like an oracle: “Do not tamper with the workings of the knowledge machine. Set its agenda, and then step back: let it run its course” [285]. Strevens does not explicitly says  who is meddling with the IRE and who would oppose it after grasping Streven’s consequentialist argument. Perhaps a few ongoing agendas in philosophy of science (and on Science and Technology Studies) could be seen as targeting the IRE. Feminist standpoint theories, for instance, defend a reassessment of what counts as evidence to illuminate potential sexist biases. Similarly, advocates for the embedment of philosophers in scientific laboratories claim that conceptual analyses can have a real impact on the advancement of science. Would any of these approaches count as threats to the IRE?

Perhaps  more serious meddlers  are the many forms of populism proliferating around the world. After all, the IRE has a technocratic taste: once their goals are set by democratic parliaments, science, like hospitals, courts, or central banks, work better as independent institutions where experts make relevant decisions according to their own rules. Challenging the autonomy of science in the name of “subjective or nonempirical considerations” would be a typical populist move. For instance, I would count as populist the call to accommodate  patients’ preferences in the design of clinical trial at the expenses of traditional debiasing methods (such as blinding). But I cannot tell whether this is the sort of challenge with which  Strevens is concerned because almost of all of the examples discussed in the book are success stories from the natural sciences before 1950.

It is always nice to be reminded of how well some scientific disciplines have worked in the past and, at least to me, the IRE seems a plausible account for this success. But I am not sure about the effectiveness of such a reminder in persuading contemporary audiences about the benefits of the autonomy of science. My first concern is that such reminders have been tried before with not much success. Reading The Knowledge Machine, I could not but think of Max Weber’s arguments about the scientific vocation. Like Strevens, Weber was inspired by how the Protestant reformation and brought about a world in which the private faith of individual agents had unintended beneficial consequences for everyone (i.e., economic growth), provided that the Church and the State were kept apart. Like Strevens, Weber praised scientific specialization and called for leaving aside all value judgments so as to prioritize consequentialist considerations. And yet the Great Method debate started because, after World War II, only Merton was persuaded that a general code of conduct was enough to account for the success of science. WillStrevens’ arguments be more persuasive today?

I agree that having clearly articulated (iron) rules will  increase the public trust in any institution. Nonetheless, my second concern is that the problem we are now facing is the increasing mistrust regarding the enforcement of any such rule. Think again of randomized clinical trials in medicine: despite the conflicting interests at stake, the systematic implementation of the IRE allows the truth about whether medical treatments work to emerge with the accumulation of evidence (thanks, e.g., to the Cochrane collaboration). And yet more and more patients are persuaded that the whole testing system is bankrupt because some particular trials are rigged by their corporate sponsors. A Weberian reminder that scientists have successfully played by the IRE in the past to everyone’s satisfaction and that we should keep their effort going will do little, in my view, to appease an audience sceptical about whether the IRE is being enforced today

But maybe I am overinterpreting Strevens’ argument. After all, defending science from the meddlers is just the topic of 7 pages out of 300. Perhaps this is just a public reminder that science works for a very simple reason that the examples in the book easily convey. It is an entertaining read and it will help to comfort any Weberian soul struggling to keep alive her faith in science in our increasingly challenging world. At least, it has helped me. 

{August, 2021}

{Metascience}

 

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Raffaella Campaner, Philosophy of medicine. Causality, Evidence and Explanation, Bologna, Archetipo Libri, 2012

For more than a decade now, there has been a growing interest in the philosophy of medicine as a scientific discipline. Already in 2005, Raffaella Campaner published a monograph in Italian on causality and explanation in medicine (Spigazione e cause in medicina: un’indagine epistemologica) showing how philosophy of science could be successfully applied to biomedical research. Throughout this decade, Campaner published a series of papers in English on the same topics that are now compiled in the reviewed volume. Most of these papers were originally published in edited collections or journals where medicine was not the central topic, so re-publishing all together in a single volume makes sense for the interested reader. Moreover, the Italian publisher has produced a decently edited but inexpensive book, so all in all philosophers of medicine should welcome it.

Campaner has gathered here 9 papers plus an introduction. Their structure is somewhat similar: the author presents different philosophical positions (mostly on causality, but also on explanation) and proceeds to illuminate them with medical case studies, arguing on this basis for her own claims. The reader will find thus an introduction to the following accounts on causality: mechanistic (Salmon, Machamer-Darden-Craven, Glennan), interventionist (Woodward) and manipulative (Price and Menzies), with a brief digression on counterfactuals (Lewis). Despite featuring on equal rank in the book’s title, we do not find introductory accounts of philosophical theories of explanation and evidence. Campaner considers instead plenty of medical explanations and evidences and see how they may fit in the different philosophical accounts of causality presented. Among her case studies, two of the most detailed are on deep brain stimulation (a therapy for Parkinson’s disease) and anti-AIDS treatments. Campaner deals also in several papers with epidemiological and psychiatric causation.

The book puts forward a pluralistic perspective on causation, showing how in actual medical practice we may find all the above mentioned approaches complementing (rather than competing with) each other. The choice often depends on the methods implemented and the context of implementation. The author does not try to construct a principled argument for causal pluralism: as she acknowledges, “lots of work is still to be done before a plausible and coherent view will be settled on and shared” (p.60). The strength of her argument is empirical: there is no evidence that a “one size fits all” concept of causation can cope with the diversity of causal approaches at work in medical practice. However, Campaner also draws on a conceptual insight emerging from this diversity: diseases would be multilevel phenomena (ranging from cells, molecules, tissues upwards to the whole organism) and medicine (siding here with Schaffner, p. 11) would be a set of middle-range theories coping with them. Campaner adopts here a sort of meta-philosophical instrumentalism regarding such deeply entrenched methodological divides such as the one opposing reductionism and anti-reductionism: as she illustrates in chapter 7, both strategies have been fruitful in medicine and both might make sense contextually. In this respect, I think is worth noticing how difficult it is to sustain even moderately pluralist stances about medical causality such as the Russo-Williamson thesis –according to which we would need mechanistic and probabilistic evidence to properly ground causal discoveries. Yet, as Campaner argues in chapter 2, medicine has been quite capable of making progress without mechanisms and yet, when we have them, we often need manipulative evidence, in addition to statistics, to properly ground them.

Campaner constantly reminds us that her pluralism does not “amount to treat all available methodological options as equal in value” (e.g., p. 133), but the book focuses mostly on cases where there is more complementarity than straightforward competition between the alternatives considered and all of them are worth, at this point in time, of scientific consideration. Historically, though, medicine has not been as peaceful as it might seem today. In The Rise of Causal Concepts of Disease (2003), for instance, K. Codell Carter has forcefully argued that scientific medicine began with the adoption of the etiological standpoint, the view that every disease has a single cause which is both necessary and sufficient for the disease, showing how this approach was crucial for progress in its treatment. Even today, I would say that medicine is not really pluralist when it comes to decision making about new therapies: we still rely on their success in randomized clinical trials as a rule. Of course, trials might be interpreted from different causal stances, but not all of them are equally captured in their design: mechanistic knowledge, for instance, does not currently qualify the value of a trial in most hierarchies of medical evidence.  In other words, as of today, philosophical pluralism about causation may faithfully reflects the way medicine is practiced, and methodological diversity may be in itself a fruitful research strategy. But I think Campaner’s claim would have been more balanced if it also considered cases in which there was open disagreement about causality between competing research agendas.

My major qualm with this volume is that the papers were not edited for the compilation. Reading it from cover to cover might be a bit reiterative sometimes since the same items are often revisited in different chapters. However, it makes it really suitable for use in undergraduate courses, in particular when teaching philosophy of science to medical students, since most concepts are explained in an accessible manner detail and illustrated with theories they will be certainly familiar with. The name index at the end is particularly helpful in tracing different approaches throughout the book and keeping the original abstracts at the beginning of each chapter is equally useful to guide the uninitiated reader. Campaner’s is thus not only a good philosophy of science in practice book, but also a very accessible book in itself.

{October 2013}

{International Studies in the Philosophy of Science 27.4 (2013), 456-458}