Article Interview: Bas van Fraassen BABIC, Joshua, COCCO, Lorenzo, HLADKY, Michal BLUNIER, David Lucas Simon (Transl.) Abstract Bas Van Fraassen is a nifty philosopher of science. He received his PhD in Pittsburgh in 1966, under the guidance of Adolf Grünbaum, he taught at Yale University, the university of Toronto, the University of Southern California, he has been McCosh Professor of Philosophy in Princeton, and eventually joined the department of philosophy at San Francisco State University, where he has the title of Distinguished Professor of Philosophy. He first gained attention with his book An Introduction to the Philosophy of Time and Space where he tried to develop a formal theory of space and time based on the notion of causality. The book had an enormous legacy, with experts of the likes of John Earman and David Malament joining the debate. However, he achieved V.I.P. status with his classic The Scientific Image, where he defends a combination of empiricism and antirealism towards unobservable entities based on a re-definition of what the scientific enterprise is. His last achievement is the tome Scientific Representation: Paradoxes of Perspectives, where he combines his scientific empiricism with the view that theories are best [...] Reference BABIC, Joshua, COCCO, Lorenzo, HLADKY, Michal, BLUNIER, David Lucas Simon (Transl.). Interview: Bas van Fraassen. iphilo - le journal des étudiants en Philosophie de l'UNIGE, 2017, vol. 9, p. 31-41 Available at: http://archive-ouverte.unige.ch/unige:105635 Disclaimer: layout of this document may differ from the published version. 1 / 1 Interview: Bas van Fraassen Bas Van Fraassen is a nifty philosopher of science. He received his PhD in Pittsburgh in 1966, under the guidance of Adolf Grünbaum, he taught at Yale University, the university of Toronto, the University of Southern California, he has been McCosh Professor of Philosophy in Princeton, and eventually joined the department of philosophy at San Francisco State University, where he has the title of Distinguished Professor of Philosophy. He first gained attention with his book An Introduction to the Philosophy of Time and Space where he tried to develop a formal theory of space and time based on the notion of causality. The book had an enormous legacy, with experts of the likes of John Earman and David Malament joining the debate. However, he achieved V.I.P. status with his classic The Scientific Image, where he defends a combination of empiricism and antirealism towards unobservable entities based on a re-definition of what the scientific enterprise is. His last achievement is the tome Scientific Representation: Paradoxes of Perspectives, where he combines his scientific empiricism with the view that theories are best thought as models or structures, rather than sets of sentences. In this interview, we talk about his philosophical influences and the birth of The Scientific Image during a journey through North-Africa, Turkey and Eastern Europe, we talk about saving the phenomena and suspending judgement over the existence of unobservable entities, living in world full of mysteries and leaving unanswerable questions unanswered, rationality and irrationality, living in a simulation, the historical interplay between theorizing and experimenting, the meaning of particle detectors for an empiricist, the unity of science and physicalism, the condemnation of Galilei by the Church, and the distinction between Appearance and Reality… Iphilo: How did you become a philosopher? Bas van Fraassen: Through books. When I was 17, working part-time in the Edmonton public library in Canada, I came across Plato’s Phaedo. That was so different from everything else I had been reading that it came as a revelation. Until that year it had not been in my mind to go to university (not at all an obvious choice for an immigrant boy), but my teachers began to suggest it. So then I told them I wanted to study philosophy. Nobody seemed to think this was a rational decision, and perhaps it wasn’t under the circumstances, but somehow it worked out. A main factor was the support of my first philosophy teacher, Karel Lambert, a logician. He gave me special directed study on logic and probability, using books newly published. Quite a different fare from the Phaedo! But in some ways not so far since Lambert liked arguing with me in the same way Socrates argued with his students. In my second year I was working part-time in the University library, and there I came upon Hans Reichenbach’s Philosophy of Space and Time. That is what led me to philosophy of science, it was my second transformative experience with a book. 1 IP: In The Scientific Image, you claim that from hearing the pattern of little feet we can infer the existence of a mouse, but from the traces in a cloud chamber we cannot infer the existence of muons or other invisible particles. It seems that the two inferences are formally identical. Why would you accept one and not the other? BvF: I do think the two cases can be given a parallel treatment, but we have to be careful about what the conclusion is that is inferred. As I suggested in that passage, the thesis that we infer to the truth of the best explanation has a rival: the thesis that we infer to its empirical adequacy. As it happens, the hypothesis that there is a mouse in the wainscoting is empirically adequate if and only if it is true. So there the two rival theses have the same implications. That is not so in the case of the hypothesis that what we see in the cloud chamber is the track of an unobservable particle – that could be empirically adequate without being true. I should add that I definitely did not suggest that rival thesis because I wanted to make it part of my epistemology! I offered it to embarrass the scientific realist with the question: which of these theses is the better explanation of our ordinary ‘inductive’ behavior? In fact, in the ordinary case of the mouse droppings etc. I already know that these indicate the presence of a mouse, with high probability, so no inductive reasoning is needed anyway. IP: How did you come to your view on science? BvF: Reichenbach’s Philosophy of Space and Time showed me a new world, the world created by the 20th century philosophers of science who took an active part in debates about the new revolutionary changes happening in physics. But Reichenbach had recently died. I found out though that another philosopher had donned his mantle, Adolf Grünbaum, and so I went to study with him in Pittsburgh. Reichenbach was a prominent logical empiricist, and his theory of space and time was of an empiricist sort, ‘relationalism’ rather than ‘absolutism’; Grünbaum continued in this vein. My first large project in philosophy of science was to continue the development of this sort of view of space, time, and space-time. I was wonderfully lucky again, for Grünbaum didn’t laugh at my naïve ambitions, he was tremendously supportive. I had another teacher in Pittsburgh, Wilfrid Sellars, prominent among the philosophers who had developed the new scientific realism in opposition to logical positivism and logical empiricism. His seminars were the most popular, his lectures fabulous, his grasp of history amazing, his writings profound. I learned a great deal from him, but unlike some of my class mates did not become a disciple. On the contrary, I felt a strong tension between his scientific realism and the empiricism that had so attracted me in Reichenbach. But I was not in any position to express a coherent contrary view at that time. The breakthrough for me came about ten years later. I had in the meanwhile worked out a relationalist, empiricist view of time, space, and space-time. On this view, there are on the one hand physical relations in the world that ground temporal and spatial judgements, and on the other hand mathematical structures that play the role of time, space, or space-time in physics. The crucial requirement is that the former, which may be scant in mathematical eyes, are embeddable in the 2 latter. There need not be anything in reality that is precisely ‘mirrored’ by the mathematical structures, as long as there is a satisfactory fit to what there is. Eventually I realized that this could be generalized to the relation between phenomena and their scientific models in general. I was very excited when that became clear, and I sent a long letter to Professor Grünbaum to outline this, from a campsite in Algeria. This was in my second full year’s leave from teaching. I was traveling with a car and tent on a large loop, starting from England and passing through North-Africa, Turkey, and Eastern Europe. I wrote the first versions of the main chapters of The Scientific Image in campsites along the way. IP: Why is it important to save the phenomena, that is to devise theories that correctly predict the observable outcome of experiments? Is it only for technological purposes? BvF: The empirical criteria of success in the sciences are exactly what need to be met for application, prediction, manipulation in their subject matter. Even in ancient times technology in that broad sense was of great value: think of the empirical success, despite theoretical error, of ancient astronomy. But there is also an intellectual value in the acquisition of empirical knowledge: not just the value of finding our way around in the world but of knowing our way around in the world. According to Wilfrid Sellars, to be in that position requires that we can answer all relevant why-questions, ex cathedra so to speak.