Wolfgang Spohn Causation, Coherence, and Concepts A Collection of Essays Wolfgang Spohn Universität Konstanz Germany ISBN 978-1-4020-5473-0 e-ISBN 978-1-4020-5474-7 Library of Congress Control Number: 2008930864 © 2008 Springer Science + Business Media B.V. No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Printed on acid-free paper 9 8 7 6 5 4 3 2 1 springer.com Meiner Mutter, der versunkenen Selbstverständlichkeit, und meinem Vater, dem schlieblich Gelassenen. Preface In this collection I present 16 of my, I feel, more substantial papers on theoretical philosophy, 12 as originally published, one co-authored with Ulrike Haas-Spohn (Chapter14), one (Chapter 15) that was a brief conference commentary, but is in fact a suitable appendix to Chapter 14, one as a translation of a German paper (Chapter 12), and one newly written for this volume (Chapter 16), which, however, is only my recent attempt to properly and completely express an argument I had given in two earlier papers. I gratefully acknowledge permission of reprint from the relevant publishers at the beginning of each paper. In disciplinary terms the papers cover epistemology, general philosophy of science, philosophy of language, and philosophy of mind. The section titles Belief, Causation, Laws, Coherence, and Concepts and the paper titles give a more adequate impression of the topics dealt with. The papers are tightly connected. I feel they might be even read as unfolding a program, though this program was never fully clear in my mind and still isn’t. In the Introduction I attempt to describe what this program might be, thus drawing a reconstructed red thread, or rather two red threads, through all the papers. This will serve, at the same time, as an overview over the papers collected. When rereading all these papers for the purpose of this edition, I thought I can still stand to each of their claims and arguments, even of the older ones. This is not true of all of my papers. This was one criterion of exclusion. In one case, though, I regret this. I considered to include also my “Stochastic Independence, Causal Independence, and Shieldability” from the Journal of Philosophical Logic 9 (1980), 73–99, since it is the first specific articulation of the foundations of the theory of Bayesian nets and their causal interpretation (that is in fact contained as a section of my German dissertation in 1976). However, this paper is my most awkward and overformalized piece, and it contains, I think, false claims about the transitivity of causation that I have corrected only in my paper reprinted here as Chapter 2. Instead, I included Chapter 4 that indicates the content of that earlier paper and comments on its relation to the leaders of the meanwhile established theory of Bayesian nets and their causal interpretation. That I can stand to all the papers collected does not mean, though, that they would satisfy me. Ever so often I was tempted to put them into clearer or simpler or new ways I had found in the meantime, to elaborate on thoughts I had only vii viii Preface hinted at, and so forth. Obviously, this would have been an unending task, and so I did not even start. The only amendments I allowed myself consist in new abstracts for all papers, in cross-references within brackets, and in a few additional footnotes marked by a dagger † and explaining where later on I have elaborated on a sketchy idea, which significance some remarks have in relation to discussions emerging only afterwards, or how I have changed my terminology. I fear my papers are not easy to read, since many of them make free use of for- mal methods. These methods are entirely natural for me, but I know, of course, that this is not a shared attitude. Are they a precondition of good philosophy? Emphatically no. The best and most important philosophers did not use them or could even not know what they are. Different fields are amenable to these methods to varying degrees. My predilection, of course, is for those fields that are so amen- able, and my ambition is to extend those fields. Where formal methods are applicable, they are certainly most useful. They open up a second layer of argument. There is then not only the level of informal argument and clarity, there is also the level of rigorous definition and proof and, this is crucial, the continuous translation between the two levels, establishing thorough checks and bal- ances. A one-layered roof is fragile, but a two-layered roof with numerous crossbeams in between is incomparably more stable. In the end, I do not know of any better way, if feasible, to improve security in the deeply insecure fields of philosophy. (In Spohn 2005c I got the opportunity to expand a bit on the character of formal philosophy.) This was the pathetic argument. There is, though, a more individual reason. There are four kinds of papers in relation to formal matters. Papers of the first category move exclusively on the formal level and are only interested in formal results; they tend to be unphilosophical unless firmly grounded in papers from the other catego- ries. The second category consists of the formally explicit philosophical papers as I mostly conceive of mine. The third kind of philosophical papers are informal, but clearly indicate that the author has the formal version in the drawer. The final kind consists of the informal papers for which no formal version exists. The ideal papers, I find, are those of the third category, readable for everyone, but rich in program and perspective. There are masters of this category I greatly admire. I feel, however, that the third category is unstable. In principle, there is a simple test for distinguishing between the third and the fourth category: simply try to pro- duce the formal version by yourself! This is either easy or impossible. In fact, though, there is a thin line between the two categories. As an author you can only be sure to write within the third category, when you actually have a formal version; the mere hope or guess it could be produced is treacherous, and the thin line is easily crossed. If you actually have the formal version, it needs checking, by readers; thus you have landed the second category. At least, this is how I perceive the matter. I always wanted to be sure to never cross the thin line, and thus could not help going on writing formally explicit papers. There are not so many occasions to express one’s gratitude. Therefore I allow myself some length. I have an abstract sense of gratefulness towards the times I am living in: peace and prosperity and the opportunity to study and study, at most hampered by one’s Preface ix own imperfections and never directly affected by the slow disasters and the sudden catastrophes ineradicable from history. In particular, I feel most privileged in hav- ing started studying philosophy in the philosophically most exciting decade of the last century. One might say that the logical revolution and thus analytic philosophy started with Frege (1879) (although it is probably more appropriate to see Frege rather as the culmination of a rich development in the 19th century – cf. Peckhaus 1997). Look at our trees and bushes, though. Many of them form their first tiny buds already in late autumn that start growing only after wintry latency and explode to blossom in spring. So it was with analytic philosophy and its execution of the logical revolution. Winter lasted till World War II. Logic was pushed forward rather in mathematics, with some radiation to the philosophy of mathematics, and those who saw its great potential in philosophy in general were few and confronted a hostile environment. Spring started only after World War II, when the intellectuals of the Vienna and Berlin circle, assisted by Quine, began their success story in United States and when Russell, Moore, and Wittgenstein and their associates began dominating British philosophy. Still, it took more than 20 years till this turned into a mass movement, relatively speaking. This required the post-war pros- perity with its fast increasing numbers of students who reached their intellectual maturity only in the late 1960s. In any case, in my perception the tree of analytic philosophy was in full blossom only around 1969 – when I started studying philo- sophy in Munich. I think I sensed my luck every day, but it took some years to fully realize it, and only much later I started seeing the (partial) history of philosophy of the 20th century in this way. Therefore, my greatest philosophical indebtedness is to Wolfgang Stegmüller. Around 1966, as a school boy, I read Stegmüller’s Hauptströmungen der Gegenwartsphilosophie (1960), read several chapters on Heidegger, Hartmann, Häberlin, etc., neither liked nor understood them, and was then totally captivated by its ch. IX on Rudolf Carnap and the Vienna Circle. Ever since I wanted to study this kind of philosophy at Stegmüller’s institute, and I did. In 1969, his institute reached its peak as well, with around eight positions for associated and assistant professors that he could maintain till his death in 1991. It must have been the largest single philosophy institute in Germany, and a unique one.