Wolfgang Spohn

It is natural and important to have a formal representation of plain belief, according to which propositions are held true, or held false, or neither. (In the paper this is called a deterministic representation of epistemic states). And it is of great philosophical importance to have a dynamic account of plain belief. AGM belief revision theory seems to provide such an account, but it founders at the problem of iterated belief revision, since it can generally account only for one step of revision. The paper discusses and rejects two solutions within the confines of AGM theory. It then introduces ranking functions (as I prefer to call them now; in the paper they are still called ordinal conditional functions) as the proper (and, I find, still the best) solution of the problem, proves that conditional independence w.r.t. ranking functions satisfies the so-called graphoid axioms, and proposes general rules of belief change (in close analogy to Jeffrey's generalized probabilistic conditionalization) that encompass revision and contraction as conceived in AGM theory. Indeed, the parallel to probability theory is amazing. Probability theory can profit from ranking theory as well since it is also plagued by the problem of iterated belief revision even if probability measures are conceived as Popper measures (see No. 11). Finally, the theory is compared with predecessors which are numerous and impressive, but somehow failed to explain the all-important conditional ranks in the appropriate way.

The central claim of the paper is, roughly, that the fact that it looks to somebody as if p is a defeasibly a priori reason for assuming that p (and vice versa), for any person, even for the perceiver himself. As a preparation, it outlines a doxastic conception suitable to explicate this claim and explains how to analyse dispositions within this conception. Since an observable p has the disposition to look as if p, this analysis generalizes to the central claim which is then argued to be at the bottom of coherentism. Thus, the defense of the claim supports coherentism as opposed to foundationalism and at the same time provides an answer to skepticism about the external world

Patrick Colonel Suppes Published with the kind permission of the Patrick Suppes Center for the History and Philosophy of Science at Stanford UniversityWe deeply mourn the death of our senior editor Patrick Suppes . After the death of Carl Gustav Hempel in 1997, who had been the senior editor since the reestablishment of ERKENNTNIS in 1975, Wilhelm Essler and I asked Pat to succeed Hempel as editor of ERKENNTNIS.Our journal was founded by Hans Reichenbach and Rudolf Carnap in 1931. It was the spearhead of what Reichenbach called scientific philosophy. Its first eight volumes were certainly among the most important documents of 20th century philosophy. However, the journal was shut down after strong anti-Semitic pressure by the Nazi regime. It was refounded by Wolfgang Stegmüller and Wilhelm Essler in 1975 as an international journal for analytic philosophy. But it continued to have a bias to ..

What may we believe? What ought we to do? These two questions, which are intended as a subtle contemporary version of the questions that concerned Kant, set the parameters of the diverse activities of the Eighth Triannual International Congress, GAP.8, of the German Gesellschaft für Analytische Philosophie (Society for Analytic Philosophy, GAP), held at the University of Konstanz at September 17–20, 2012. These questions remain central systematic questions of theoretical and practical philosophy.The six articles collected here are the main papers presented at that congress. They can be divided into two groups. First, there are Peter M. S. Hacker’s opening lecture, Ulrich Blau’s Erkenntnis lecture which was sponsored by Springer Publishers, and Roy Sorensen’s closing lecture. Second, there are three papers which are all connected to the author’s symposium held in honour of Rüdiger Bittner, who received the 2012 Frege-Prize of the Gesellschaft für Analytische Philosophie for a distinguis

This paper deals with Hans Reichenbach's common cause principle. It was propounded by him in, and has been developed and widely applied by Wesley Salmon, e.g. in and. Thus, it has become one of the focal points of the continuing discussion of causation. The paper addresses five questions. Section 1 asks: What does the principle say? And section 2 asks: What is its philosophical significance? The most important question, of course, is this: Is the principle true? To answer that question, however, one must first consider how one might one argue about it at all. One can do so by way of examples, the subject of section 3, or more theoretically, which is the goal of section 4. Based on an explication of probabilistic causation proposed by me in,, and, section 4 shows that a variant of the principle is provable within a classical framework. The question naturally arises whether the proved variant is adequate, or too weak. This is pursued in section 5. My main conclusion will be that some version of Reichenbach's principle is provably true, and others may be. This may seem overly ambitious, but it is not. The paper does not make any progress on essential worries about the common cause principle arising in the quantum domain; it only establishes more rigorously what has been thought to be plausible at least within a classical framework

The modalities come into the world by being projections or objectivizations of our epistemic constitution. Thus this paper is a statement of Humean projectivism. In fact, it goes beyond Simon Blackburn’s version. It is also designed as a comprehensive counter-program to David Lewis’ program of Humean supervenience. In detail, the paper explains: Already the basic fact that the world is a world of states of affairs is due to the nature of our epistemic states. Objects, which figure in states of affairs and which embody metaphysical modality, are constitutable by their essential properties and in fact constituted by us according to our ontological policies. What the facts are, to which the correspondence notion of truth refers, is determined by applying an epistemic or pragmatic notion of truth to the world. Causation is a specific objectivization of our conditional beliefs. Nomicity is a ‘habit of belief’, a specific way of generalizing epistemic attitudes. This covers the basic metaphysical and natural modalities. The paper attempts to convey that talking of projection or objectivization is not just imagery, but a constructively realizable program.

The characteristic difference between laws and accidental generalizations lies in our epistemic or inductive attitude towards them. This idea has taken various forms and dominated the discussion about lawlikeness in the last decades. Hence, ranking theory with its resources of formalizing defeasible reasoning or inductive schemes seems ideally suited to explicate the idea in a formal way. This is what the paper attempts to do. Thus it will turn out that a law is simply the deterministic analogue of a sequence of independent, identically distributed random variables. This entails that de Finetti‘s representation theorems can be directly transformed into an account of confirmation of laws thus conceived.

This paper compares the epistemological conception of Isaac Levi with mine. We are joined in both giving a constructive answer to the relation of belief and probability, without reducing one to the other. However, our constructions differ in at least nine more or less important ways, all discussed in the paper. In particular, the paper explains the similarities and differences of Shackle's functions of potential surprise, as used by Levi, and my ranking functions in formal as well as in philosophical respects. The appendix explains how ranking and probability theory can be combined in the notion of a ranked probability measure (or probabilified ranking function)

  The characteristic difference between laws and accidental generalizations lies in our epistemic or inductive attitude towards them. This idea has taken various forms and dominated the discussion about lawlikeness in the last decades. Likewise, the issue about ceteris paribus conditions is essentially about how we epistemically deal with exceptions. Hence, ranking theory with its resources of defeasible reasoning seems ideally suited to explicate these points in a formal way. This is what the paper attempts to do. Thus it will turn out that a law is simply the deterministic analogue of a sequence of independent, identically distributed random variables. This entails that de Finetti's representation theorems can be directly transformed into an account of confirmation of laws thus conceived

The paper is motivated by the need of accounting for the practical syllogism as a piece of defeasible reasoning. To meet the need, the paper first refers to ranking theory as an account of defeasible descriptive reasoning. It then argues that two kinds of ought need to be distinguished, purely normative and fact-regarding obligations (in analogy to intrinsic and extrinsic utilities). It continues arguing that both kinds of ought can be iteratively revised and should hence be represented by ranking functions, too, just as iteratively revisable beliefs. Its central proposal will then be that the fact-regarding normative ranking function must be conceived as the sum of a purely normative ranking function and an epistemic ranking function (as suggested in qualitative decision theory). The distinctions defends this proposal with a comparative discussion of some critical examples and some other distinctions made in the literature. It gives a more rigorous justification of this proposal. Finally, it starts developing the logic of purely normative and of fact-regarding normative defeasible reasoning, points to the difficulties of completing the logic of the fact-regarding side, but reaches the initial aim of accounting for the defeasible nature of the practical syllogism.

Rudolf Carnap was born on May 18, 1891, and Hans Reichenbach on September 26 in the same year. They are two of the greatest philosophers of this century, and they are eminent representatives of what is perhaps the most powerful contemporary philosophical movement. Moreover, they founded the journal Erkenntnis. This is ample reason for presenting, on behalf of Erkenntnis, a collection of essays in honor of them and their philosophical work. I am less sure, however, whether it is a good time for resuming their philosophical impact; their work still is rather part than historical basis of the present philosophical melting-pot. Their basic philosophical theses have currently, it may seem, not so high a standing, but their impact can be seen in numerous detailed issues; they have opened or pushed forward lively fields of research which are still very actively pursued not only within philosophy, but also in many neighboring disciplines. Whatever the present balance of opinions about their philosophical ideas, there is something even more basic in their philosophy than their tenets which is as fresh, as stimulating, as exemplary as ever. I have in mind their way of philosophizing, their conception of how to do philosophy. It is always a good time for reinforcing that conception; and if this volume would manage to do so, it would fully serve its purpose.

Objective standards for justification or for being a reason would be desirable, but inductive skepticism tells us that they cannot be presupposed. Rather, we have to start from subjective-relative notions of justification and of being a reason. The paper lays out the strategic options we have given this dilemma. The paper explains the requirements for this subject-relative notion and how they may be satisfied. Then it discusses four quite heterogeneous ways of providing more objective standards, which combine without guaranteeing complete success.