The Content of This Volume

There are many different kinds of new scientific realism and it would not be reasonable to pretend to ‘make the point' on them. It seems more useful to present a limited sample of some of the most significant and best characterized of them, while a comprehensive view can be offered by outlining certain debates occurred in the history of Western epistemology which have constructed the conceptual back­ground and framework of the present discussions on scientific realism.

After the Introduction, the book contains a Prologue and three Parts.

The Prologue opens with a chapter by Mario Alai, The Debates on Scientific Realism Today: Knowledge and Objectivity in Science, which considers the dis­cussions on scientific realism as a well-defined and specialized domain of the philosophy of science, that has been characterized in a very large amount of books and papers, and offers a detailed survey of this production according to a clear classification that helps very much the understanding of this composite mosaic and the often subtle reasons of its inner articulation. Beside its great informative value, this chapter has the important function of compensating, thanks to its practical completeness, the unavoidable limitation due to the restricted number of chapters in which only certain of the most salient positions on scientific realism are presented in this work. Moreover, it has the merit of being an updated portrayal of the state of the art in this domain, which was badly needed considering the rare occurrence of such synthetic overviews.

The second chapter of this Prologue is the contribution by Evandro Agazzi, The Truth of Theories and Scientific Realism, in which the sciences are considered in their theoretical-conceptual and linguistic aspect as well as in their practical-operational aspect. In such a way the legitimate referential sense of the concept of truth is rescued, which can be applied also to scientific theories, and this justifies attributing a genuine ‘reality’ also to the referents of the theoretical con­cepts, within their respective ‘regional ontology’. This chapter aims at outlining the thematic horizon in which the further contributions of this work are inscribed.

The chapters of the following three parts are organized according to a minimal logical order in which contributions are distributed according to the more general issues of the scientific realism debate, the different typologies of such realism, and its consideration in a few specialized sciences.

The articles in Part One deal with general problems and arguments in the discussion between scientific realism and antirealism. Alan Musgrave (Strict Empiricism versus Explanation in Science) presents the explanatory task of science and philosophy as the decisive reason for realism, especially in his own original version of the inference to the best explanation and the no miracle argument as inferences to the reasonableness of believing that theories are true. He then con­tends that van Fraassen’s and Stanford’s “surrealist” accounts cannot explain sci­entific success, and counters Laudan’s historical objections by arguing that the novel predictions of false theories either were not novel or can be explained by partial truth.

In his contribution Bas van Fraassen (Misdirection and Misconception in the Scientific Realism Debates) points out that current debates on scientific realism are often affected by misrepresentations of what the respective positions are. Once the issues are clarified, it turns misrepresentaions out that the question is not an ontological one (what there is), but about what is science, what are its adequacy criteria, and what epistemic and doxastic attitudes toward theories we should take. Realists and empiricists can cooperate in solving these questions, taking inspiration from Weyl, Glymour, and Suppe.

Against the background of the model-theoretic conception of theories, Michel Ghins (Scientific Realism: Representation, Objectivity and Truth) discusses the criteria by which scientific theories can be taken to represent unobservable entities objectively, and the difference between the faithfulness of representations and the truth of propositions.

Marco Buzzoni (Robustness and Scientific Realism) argues for a technical-experimental interpretation of robustness, which bridges between robustness conceived as the support coming to hypotheses from independent but convergent sources (Whewell, Wimsatt, Hacking, Glymour, Kosso, etc.), and robustness conceived as the stability of an engineered or biological system. This intermediate notion can also provide an improved no miracles argument, escaping Hacking's charge of begging the question.

In earlier works Thomas Nickles (The Temptations of Scientific Realism: Cognitive Illusions, Objections, and Replies) studied some cognitive illusions which may underlie the confidence in realism: that the course of scientific research has now come to its final goal, that our theories are fully mature and non-problematic, that no revolutionary or long-term evolutionary change is for-seeable in the future. As a result, he now suggests a more guarded agnostic and pragmatist position, defending it from various possible objections. Moreover, he points out that all the moves and attitudes which seemingly make realism more robust are also available to pragmatists.

Gerhard Vollmer (Why do Theories Fail? An Argument for Realism) is also critical of the most common argument for realism, that from the success of scientific theories: confirmation by success is an instance of the ‘affirming the consequent' fallacy, so it may well happen that theories are successful yet false. The strongest argument for realism, instead, is its capacity to explain unsuccess: theories fail, when they so do, because the world is different from what they say. Since antire­alists lack an equally plausible explanation, realism is to be preferred.

In the last chapter of this Part Fabio Minazzi (The Epistemological Problem of the Objectivity of Knowledge) discusses the general question of the objectivity of human knowledge from the point of view of logical neo-realism, but significantly drawing also on Husserl's concept of “regional ontologies”, Bachelard's notion of ontogenese, the tradition of criticism, and Agazzi's analysis of objectivity in its epistemic contexts.

Some recent conceptions of scientific realism are discussed and defended in Part Two.

Stathis Psillos (Scientific Realism and the Mind-Independence of the World) defends the view that the realist claim of mind-independence is captured by what he calls ‘the possibility of divergence', viz., the possibility of a gap between what there is in the world and what is issued as existing by a suitable set of epistemic practices. The realist commitment to mind-independence is split into two components: irre­ducible existence and objective existence, and it is shown that various versions of anti-realism compromise one or both of these conditions.

The role of metaphysics is also scrutinized by Steven French (Structural Realism and the Toolbox of Metaphysics). In his view philosophers of science should not dismiss it, but draw from it whatever “tools” and conceptual devices may serve to articulate their conceptions. In particular, the paper provides examples of how certain metaphysical “maneuvers” may help in framing a structural realist account of science.

Alberto Cordero (Retention, Truth-Content and Selective Realism) discusses the best way to develop selective realism, currently the most plausible realist position. He argues that Saatsi's, Vickers', and Votsis' strategy, committed only to the minimal components indispensable to derive predictions, is unnecessarily weak, and neglects the realist import of explanatory success. Hence, he proposes a naturalistic generalization of that strategy, whereby the theory-parts worth of realist commitment are selected through the confirmation criteria actually employed by scientists, including both predictive and explanatory power, and absence of reasonable doubts.

In the last paper of Part Two Hans Lenk (A Scheme-Interpretationist Actionistic Realism) puts forward a scheme-interpretationist and actionistic form of scientific realism: we can grasp the world and act on it only within and relative to interpretive perspectives and methodological schematizations.

Finally, the contributions in Part Three concern realism in some particular sciences or disciplines. From the point of view of logical semantics, scientific theories are ordered sets of propositions, whose models are abstract algebraic structures. But through and beyond these abstract models theories must be con­nected to the real concrete world. Jan Wolensky (The Semantic Definition of Truth, Empirical Theories and Scientific Realism) shows how this can be achieved through the concept of empirical valuation, thus allowing to phrase scientific realism in terms of the semantic theory of truth.

Dennis Dieks and Roland Omnes debate the realism question in quantum mechanics. Dieks (Realism and Objectivity in Quantum Mechanics) considers the general antirealist argument that in principle any body of data may be accounted for by numberless empirically equivalent theories. Realists have replied that in actual scientific practice cases of empirically equivalent theories are very rare or inexis- tent; when two theories are equally compatible with the evidence available at some particular time, new evidence can soon break the tight; and theories may enjoy different confirmation in spite of having the same empirical consequences. However Dieks points out that these replies encounter serious difficulties in quantum mechanics, where many incompatible interpretations are nonetheless strictly empirically equivalent. These instances of empirical underdetermination, therefore, are much more telling for the realism debate than many standard philosophical examples.

Another great obstacle to realism in quantum mechanics is considered to be the incompatibility of Schrodinger's equation with the collapse of wave functions. However Omnes (Is Uniqueness of Reality Predicted by the Quantum Laws?) draws attention on the “local entanglement”, a phenomenon directly deriving from the same equation but scarcely discussed in the literature. It has recently been found to have some interesting properties, which in the presence of fluctuations in the environment could generate the collapse. If conclusively proved, this would rec­oncile Schrodinger’s equation with the wave-function collapse, so solving a major problem in the philosophy of quantum mechanics.

The next two contributions concern cognitive sciences. Jean Guy Meunier (Theories and Models: Realism and Objectivity in Cognitive Science) explains that in disciplines like psychology, philosophy and computer sciences the method­ological and epistemic ideal of objectivity is less easily pursued than in the “hard” sciences. In fact, cognitive sciences are often related to their objects by a hierarchy of models: a conceptual model couched in the natural language, a computational model, and a simulation model, which instantiates the computational model in a physical computer process. One must therefore look at the relations between these models and reality in order to understand what exactly is the import of scientific realism when dealing with these disciplines.

Instead Vladislav Lektorski (Realism as the Methodological Strategy in Cog­nitive Science) argues for realism as a methodological strategy and the adequate interpretation of situated and embodied cognitive science, where actions and operations play a key role in linking cognition to the real world. He criticizes Fodor’s “methodological solipsism” and Varela’s attempt to overcome the realism-idealism dichotomy. Against this background he also discusses Gibson’s notion of affordance and some prominent philosophical positions: entity realism, constructive realism, externalism, in particular active externalism, and the activity approach in Russian psychology and epistemology.

Amparo Gomez (Mechanisms, Capacities, and Entity Realism in Social Sciences) believes that scientific realism needs to rely on a metaphysics of causa­tion. Today causes are mainly conceived in two alternative ways: as mechanisms, and as dispositions or powers. The former conception must explain how are mechanisms able to cause, and according to Gomez they do so because they realize properties, hence powers or capacities. Thus, in a sense, the two rival views of causality become mutually complementary. This however involves a particular treatment of powers, similar to Mumford’s, Chakravartty’s and Bird’s, and alter­native to Ellis’ new essentialism.

The last two papers in the volume concern mathematics. While in the physical sciences realism conceives objects as representation-independent, Gerhard Heinzmann (Objectivity in Mathematics: The Structuralist Roots of a Pragmatic Realism) points out that mathematical entities are more naturally considered as existing and being so-and-so only to the extent that they are represented and proved by us. Thus, while in the physical sciences there can be a strong objectivity but no assurance of truth, here “objectivity” is proof, hence it guarantees truth. Moreover, there seems to be no role for explanation or explanatory evidence, here. According to Heinzmann, however, a pragmatic interpretation of mathematical practice might show that there are “explanatory proofs” after all: viz., proofs which derive the content of the conclusion from that of the premises by intuitive “seemings” and topic-specific mathematical representations.

Also Reinhard Kahle (Mathematical Truth Revisited: Mathematics as a Toolbox) discusses the specificities of truth and existence in mathematics, often conceived as conditional or relative to a framework, like in Bernays or Carnap. Thus, even “non-standard” structures may be admitted as useful, rather than as true in some absolute sense.

Acknowledgements More than half of the chapters of this book are revised versions of invited papers presented at the Congress of the International Academy of Philosophy of Science (IAPS) held on September 23-25, 2015 at the University of A Coruna (Spain) on the theme Scientific Realism: The Problem of Objectivity and Truth in Science. The program of that conference was jointly prepared by Evandro Agazzi (President) and Wenceslao Gonzalez (Member) of the IAPS. A special thanks goes to the latter also for the impeccable organization of the meeting, and to the University of A Coruna and the Deputation of A Coruna for their financial support. Mario Alai (Member of the IAPS) has greatly helped in the editing of this volume.