Michel Ghins and I are both empiricists, and agree significantly in our critique of “traditional” empiricist epistemology. We differ however in some respects in our interpretation of the scientific enterprise. Ghins argues for a moderate scientific realism which includes the view that acceptance of a scientific theory will bring with it belief in the existence of all those entities, among the entities the theory postulates, that satisfy certain criteria. For Ghins these criteria derive from the criteria for legitimate affirmation of (...) existence for any entities, the directly observable ones not being privileged in that respect. They are roughly that the putatively existing entity should according to the accepted theory manifest itself in our experience, and display a certain permanence and invariance. My disagreement on this topic derives from a larger difference concerning the relation between experience, existence, and theory. (shrink)

Constructive empiricism, the view introduced in The Scientific Image, is a view of science, an answer to the question "what is science?" Arthur Fine's and Paul Teller's contributions to this symposium challenge especially two key ideas required to formulate that view, namely the observable/unobservable and acceptance/belief distinctions. I wish to thank them not only for their insightful critique but also for the support they include. For they illuminate and counter some misunderstandings of Constructive Empiricism along the way. That leaves me (...) free to focus on those two main challenges. (shrink)

In the present paper I want to do two things. First, I want to discuss Ramsey’s own views of Ramsey-sentences. This, it seems to me, is an important issue not just (or mainly) because of its historical interest. It has a deep philosophical significance. Addressing it will enable us to see what Ramsey’s lasting contribution in the philosophy of science was as well as what its relevance to today’s problems is. Since the 1950s, where the interest in Ramsey’s views has (...) mushroomed, there have been a number of different ways to read Ramsey’s views and to reconstruct Ramsey’s project. The second aim of the present paper is to discuss the most significant and controversial of this reconstruction, viz., structuralism. After some discussion of the problems of structuralism in the philosophy of science, as this was exemplified in Bertrand Russell’s and Grover Maxwell’s views and has re-appeared in Elie Zahar’s and John Worrall’s thought, I will argue that, for good reasons, Ramsey did not see his Ramsey-sentences as part of some sort of structuralist programme. I will close with an image of scientific theories that Ramsey might have found congenial. I will call it Ramseyan humility. (shrink)

The recent debate around scientific realism has taken an epistemic turn. The issue is no longer whether theoretical discourse is or is not assertoric (truth-valuable), nor whether theoretical discourse can be reduced to observational discourse. All sides of the present debate have left behind traditional instrumentalism and reductive empiricism. Instead, they endorse semantic realism which suggests that theoretical discourse (that is, statements about theoretical entities) should be understood literally and be taken to be assertoric and irreducible. In this setting, the (...) philosophical reaction to realism challenges the grounds for the realists’ belief in the existence of the unobservable entities posited by theories and in the truth of the assertions made about them. This reaction can take different shapes. But the dominant one, coming from van Fraassen’s constructive empiricism, is that an empiricist cannot be rationally forced to be a scientific realist. In his view, an empiricist can understand scientific theories literally but remain agnostic as to the truth (or falsity) of their theoretical assertions. Besides, if an empiricist decides to accept a theory he accepts it not as true but as empirically adequate. (shrink)

James Ladyman has argued that constructive empiricism entails modal realism, and that this renders constructive empiricism untenable. We maintain that constructive empiricism is compatible with modal nominalism. Although the central term 'observable' has been analyzed in terms of counterfactuals, and in general counterfactuals do not have objective truth conditions, the property of being observable is not a modal property, and hence there are objective, non-modal facts about what is observable. Both modal nominalism and constructive empiricism require clarification in the face (...) of Ladyman's argument. But we also argue that, even if Ladyman were right that constructive empiricism entails modal realism, this would not be a problem for constructive empiricism. (shrink)

In his book, The Scientific Image, van Fraassen lucidly draws an alternative to scientific realism, which he calls "Constructive Empiricism". In this epistemological theory, the concept of observability plays the pivotal role: acceptable theories may be believed only where what they say solely concerns observables. Van Fraassen develops a concept of observability which is, as he admits, vague, relative, science-dependent, and anthropocentric. I draw out unacceptable consequences of each of these aspects of his concept. Also, I argue against his assumption (...) that "empirical adequacy" is the same thing as "saving the phenomena", according to his sense of the expressions. (shrink)

In the fusillade he lets fly against Foss (1984), Bourgeois (1987) sometimes hits a live target. I admit that I went beyond the letter of van Fraassen's The Scientific Image (1980), making inferences and drawing conclusions which are often absurd. I maintain, however, that the absurdities must be charged to van Fraassen's account. While I cannot redress every errant shot of Bourgeois, his essay reveals the need for further discussion of the concepts of the phenomena and the observables as used (...) by van Fraassen. (shrink)

The attempt to formulate a viable empiricist and non-foundationalist epistemology of science faces four problems here confronted. The first is an apparent loss of objectivity in science, in the conditions of use of models in applied science. The second derives from the theory-infection of scientific language, with an apparent loss of objective conditions of truth and reference. The third, often cited as objection to The Scientific Image, is the apparent theory-dependence of the distinction between what is and is not observable. (...) The fourth and last is the loss of the possibility of objective evaluation of rationality in scientific methodology. It is argued that each of these problems is illusory. (shrink)