Michel Ghins

Although Kuhn is much more an antirealist than a realist, the earlier and later articulations of realist and antirealist ingredients in his views merit close scrutiny. What are the constituents of the real invariant World posited by Kuhn and its relation to the mutable paradigm-related worlds? Various proposed solutions to this problem (dubbed the "new-world problem" by Ian Hacking) are examined and shown to be unsatisfactory. In The Structure of Scientific Revolutions, the stable World can reasonably be taken to be made up of ordinary perceived objects, whereas in Kuhn's later works the transparadigmatic World is identified with something akin to the Kantian world-in-itself. It is argued that both proposals are beset with insuperable difficulties which render Kuhn's earlier and later versions of antirealism implausible.

In his Scientific Representation. Paradoxes of Perspective, Bas van Fraassen offers a pragmatic account of scientific representation and representation tout court. In this paper I examine the three conditions for a user to succeed in representing a target in some context: identification of the target of the representational action, representing the target as such and correctly representing it in some respects. I argue that success on these three counts relies on the supposed truth of some predicative assertions, and thus that truth is more fundamental than representation. I do this in the framework of a version of the so-called “structural” account of representation according to which the establishment of a homomorphism by the user between a structure abstracted from the intended target and some relevant structure of the representing artefact is a necessary condition of success for representing the target in some respects. Finally, on the basis of a correspondence view of truth, I show that it is possible to address what van Fraassen calls “the loss of reality objection”.

This book addresses central issues in the philosophy and metaphysics of science, namely the nature of scientific theories, their partial truth, and the necessity of scientific laws within a moderate realist and empiricist perspective. Accordingly, good arguments in favour of the existence of unobservable entities postulated by our best theories, such as electrons, must be inductively grounded on perceptual experience and not their explanatory power as most defenders of scientific realism claim. Similarly, belief in the reality of dispositions such as causal powers which ground the natural necessity of scientific laws must be based on experience. Hence, this book offers a synthetic presentation of an original metaphysics of science, namely a metaphysics of properties, both categorical and dispositional, while at the same time opposing strong versions of necessitarism according to which laws are true in all possible worlds. The main theses and arguments are clearly presented in a non-technical way. Thus, on top of being of interest to the specialists of the topics discussed, it is also useful as a textbook in courses for third year and more advanced university students.

Representation and models have been the focus of considerable interest in philosophy of science for several decades. But the publication in 2008 of Bas van Fraassen’s important book Scientific representation: Paradoxes of perspective gave a novel and strong impetus to the study of their role in the dynamic of scientific knowledge, as attested by the growing quantity of papers and conferences related to representation. In science, knowing necessarily involves representing—phenomena at least and perhaps more for the scientific realist—by means of mathematical structures. Even if these structures are not, as van Fraassen aptly insists, mental ideas, scientific activity is still evolving within the modern Cartesian “épistèmè de la representation” as Michel Foucault famously put it.This book is a welcome collection of exciting papers which grew out of a Workshop on representation and models organized on 11–12 March in Ferrol, at the University of A Coruña . Most papers are devoted to ..

After a brief presentation of what I believe to be the main features of the modelling démarche in science, I will focus on the basic following question: how can an abstract entity - a model - possibly represent an existing observable entity, which is phenomenally accessible to us, but which is not abstract? This is what Bas van Fraassen calls the loss of reality objection. Instead of proposing a pragmatic dissolution of this objection as van Fraassen does, I will argue that scientific representing necessarily involves a homomorphism between structures and thus that, in a strict technical sense of representation, phenomena are not represented by our models but only as having some specific properties belonging to the domains of our representing structures. Yet, our contact with phenomenal entities is secured by propositions that are true in a correspondence sense. The truth of these - ontic - propositions which state that phenomenal entities possess some precise properties is the soil on which the informative content of our successful representations rest.

In this paper, I briefly present the regularity and necessity views and assess their difficulties. I construe scientific laws as universal propositions satisfied by empirically successful scientific models and made — approximately — true by the real systems represented, albeit partially, by these models. I also conceive a scientific theory as a set of models together with a set of propositions, some of which are laws. A scientific law is a universal proposition or statement that belongs to a scientific theory. Scientific laws also are laws of nature since we can provide arguments in favour of natural causal powers that ground the truth of laws. I argue that the truth of counterfactual conditional statements and the occurrence of regularities in nature provide good reasons to believe that real causal powers exist in nature and that the truth of scientific laws is based on a metaphysics of nature

L’opposition d’Ernst Mach à l’existence de l’espace absolu et à celle des atomes fait partie des lieux communs de l’histoire de la philosophie des sciences. Mais cette opposition est souvent exagérée et, de plus, mal comprise. La plupart du temps, son attitude anti-réaliste en ce qui concerne l’espace absolu, les atomes et les entités théoriques en général est interprétée comme une conséquence immédiate de sa position empiriste, parfois qualifiée de « sensationnaliste »ii. Cette idée reçue (défendue entre autres par John Blackmore [1972]) sur les thèses de Mach en matière d’épistémologie - et j’entends par ce terme d’épistémologie une conception philosophique de la connaissance en général (Erkenntnislehre) et pas seulement de la connaissance scientifique - comporte une grande part de vérité. Mais une part de vérité seulement. En réalité, les objections soulevées par Mach contre une interprétation réaliste des théories scientifiques – et qui sont moins radicales qu’on ne le pense habituellement – reposent également sur des considérations méthodologiques qui relèvent davantage de la philosophie des sciences (Wissenschaftlehre). On verra d’ailleurs que la pensée de Mach montre une grande cohérence, et même une continuité, entre sa philosophie de la connaissance d’une part, et sa philosophie de la connaissance ordinaire et des sciences d’autre part. Je présenterai d’abord les traits saillants des positions de Mach en ce qui concerne la connaissance humaine en général; ensuite, j’examinerai ses objections à l’encontre de l’espace absolu et, de façon plus détaillée, celles soulevées contre les atomes. Je me pencherai enfin sur les relations entre ces objections et sa prise de position empiriste. Cette analyse nous permettra de mieux comprendre la nature exacte de l’antiréalisme de Mach. Je tenterai de montrer que Mach peut être qualifié – même si cela peut paraître surprenant - de « réaliste scientifique » dans la mesure où certaines entités théoriques possèdent le même statut d’existence, prise en un sens faible, que les objets ordinaires.

In this paper I argue in favour of a moderate and selective version of scientific realism with respect to the existence of some physical theoretical objects and the truth of some statements about them. The analysis of common sense or ordinary experience reveals that existence and truth assertions concerning familiar objects are warranted if they satisfy what we call the criteria of presence and invariance. Ordinary objects exemplify a form or a structure determined by constant and changing features with respect to the variation of the conditions of observation and a content given in sensory presence. It is claimed that some theoretical physical objects that possess a structure or a form determined by invariant and variable characteristics relatively to a specified group of transformations and a content provided by observations on which the measurement of those characteristics is grounded can also be justifiably asserted to exist. We further show that this defence of scientific realism in physics doesn't fall prey to the objections that have been raised against the usual vindication of scientific realism based on the no-miracle argument. Some standard objections to scientific realism, such as the underdetermination of theories by observations and the pessimistic meta-induction, are examined and shown to be unconvincing

After a brief presentation of what I take to be the representational démarche in science, I stress the fundamental role of true judgements in model construction. The success and correctness of a representation rests on the truth of judgements which attribute properties to real targeted entities, called “ontic judgements”. I then present what van Fraassen calls “the Loss of Reality objection”. After criticizing his dissolution of the objection, I offer an alternative way of answering the Loss of Reality objection by showing that the contact of our models with reality is grounded on the truth of ontic judgements. I conclude by examining.

A scientific mathematical law is causal if and only if it is a process law that contains a time derivative. This is the intrinsic criterion for causal laws we propose. A process is a space-time line along which some properties are conserved or vary. A process law contains a time variable, but only process laws that contain a time derivative are causal laws. An effect is identified with what corresponds to a time derivative of some property or magnitude in a process law, whereas the other terms correspond to the cause(s). According to our criterion, causes are simultaneous with their effects and causality has no temporal direction. Several examples from natural and social disciplines support the applicability of our criterion to all scientific laws. Various objections to our proposal are presented and refuted. The merits our intrinsic theory of causality vis-à-vis the Salmon–Dowe conserved quantity theory are discussed.

After a presentation of some relevant aspects of Chakravartty's semi-realism (A Metaphysics for scientific realism. Knowing the unobservable. Cambridge University Press, Cambridge, 2007), this paper addresses two difficulties that appear to be inherent to important components of his proposed metaphysics for scientific realism. First, if particulars and laws are concrete structures, namely actual groupings of causal properties as the semirealist contends, the relation between particulars and laws becomes also a relation between particulars with some annoying consequences. This worry—and some others—are resolved if laws are taken to be statements and particulars are construed not only as groupings of properties, but things that contain a non-conceptual ingredient which can be given in perceptual awareness. Second, on the semirealist's view of particulars it becomes difficult to defend an epistemological version of scientific realism according to which we have good reasons to believe that the same things are referred to despite the fact that successive theories may attribute different properties to them