Michel Ghins

Cet ouvrage reprend l'essentiel des discours prononces et des communications presentees lors du colloque qui s'est tenu le 16 novembre 2001 a l'Institut Superieur de Philosophie en l'honneur des 80 ans de Jean Ladriere. On y trouve, outre les discours de Marcel Crochet, Gilbert Gerard et Michel Molitor, une contribution importante de Jean Ladriere et des communications de Stanislas Breton, Bernard d'Espagnat, Dominique Lambert, Jean-Francois Malherbe, James Pembrun, Andre Van de Putte et Philippe Van Parijs. Toutes les interventions portent sur la problematique de la rationalite - un theme central et unificateur de l'oeuvre philosophique de Jean Ladriere - dans les domaines de l'histoire de la philosophie, la philosophie sociale et politique, la philosophie du langage, la philosophie des sciences et la theologie. L'ouvrage se termine par une interview de Jean Ladriere par Philippe Van Parijs."

Explanationist strategies for defending epistemological scientific realism make heavy use of a particular version of inference to the best explanation known as the no-miracle argument. I consider ESR to be a genuinely philosophical—non-naturalistic—thesis which contends that there are strong arguments to believe in some non-observational claims made by scientific theories that are partially observationally correct. In this paper, I examine the grounds of the strength of these arguments from what I call a contemplative perspective which focuses on the end products, i.e. theories, of the scientific activity as opposed to the pragmatist view which considers science to be primarily an activity. I briefly rehearse the main difficulties of the no-miracle argument and of inference to the best explanation in general. I argue that a convincing defence of ESR should be based on the empirically ascertained reality of causal connections between theoretical entities which possess properties that are in principle observable and the results of measurements or observations. The knowledge of those causal connections may well deliver an—even the best—explanation of the appearances. But belief in the existence of some unobservable entities is mainly justified by their empirically attested causal role, not on their possible explanatory function.

This paper is devoted to an analysis of some aspects of Bas van Fraassen’s views on representation. While I agree with most of his claims, I disagree on the following three issues. Firstly, I contend that some isomorphism between the representor and what is represented is a universal necessary condition for the success of any representation, even in the case of misrepresentation. Secondly, I argue that the so-called “semantic” or “model-theoretic” construal of theories does not give proper due to the role played by true propositions in successful representing practices. Thirdly, I attempt to show that the force of van Fraassen’s pragmatic - and antirealist - “dissolution” of the “loss of reality objection” loses its bite when we realize that our cognitive contact with real phenomena is achieved not by representing but by expressing true propositions about them

On the basis of an analysis of everyday experience and practice, criteria of legitimate assertions of existence and truth are offered. A specific object, like a newspaper, can be asserted to exist if it has some invariant characteristics and is present in actual perception. A statement, like “This newspaper is black and white,” can be accepted as true if it is well-established in some empirical domain. Each of these criteria provides a sufficient condition for acceptance of existence and truth, respectively, at the empirical level. Following Herman Weyl, it is argued that these criteria can be extended to the scientific theoretical level to support a selective and moderate version of scientific realism according to which entities like the electromagnetic and gravitational fields, but not crystalline spheres or some topological manifolds, can legitimately be asserted to exist

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.

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.

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”.

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