Wolfgang Spohn

When I talk about the objects of belief I do not mean, e.g., the sun to which my thought that the sun will rise tomorrow refers; I do not mean the objects we think about. I take objects rather in a general philosophical sense; they simply are the bearers of properties and the relata of relations. I am thus concerned with the objects that are related by the belief relation „_a_ believes that _p_“. In this scheme „ _a _“ represents a person or an epistemic subject; but I am not going to discuss what a person is. „ _p _“ or „that _p _“ represents an object, namely the object of belief; and I am going to discuss what this is. In other words, I am interested in belief contents – to use a less neutral, narrower and equally unclear term

Meets what? Ranking theory is, as far as I know, the only existing theory suited for underpinning Keith Lehrer’s account of knowledge and justification. If this is true, it’s high time to bring both together. This is what I shall do in this paper. However, the result of defining Lehrer’s primitive notions in terms of ranking theory will be disappointing: justified acceptance will, depending on the interpretation, either have an unintelligible structure or reduce to mere acceptance, and in the latter interpretation knowledge will reduce to true belief. Of course, this result will require a discussion of who should be disappointed. So, the plan of the paper is simple: In section 1 I shall briefly state what is required for underpinning Lehrer’s account and why most of the familiar theories fail to do so. In section 2 I shall briefly motivate and introduce ranking theory. Basing Lehrer’s account on it will be entirely straightforward. Section 3 proves the above-mentioned results. Section 4, finally, discusses the possible conclusions.

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

  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 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 paper proposes to amend structuralism in mathematics by saying what places in a structure and thus mathematical objects are. They are the objects of the canonical system realizing a categorical structure, where that canonical system is a minimal system in a specific essentialistic sense. It would thus be a basic ontological axiom that such a canonical system always exists. This way of conceiving mathematical objects is underscored by a defense of an essentialistic version of Leibniz’ principle according to which each object is uniquely characterized by its proper and possibly relational essence (where “proper” means “not referring to identity").

The paper is based on ranking theory, a theory of degrees of disbelief (and hence belief). On this basis, it explains enumerative induction, the confirmation of a law by its positive instances, which may indeed take various schemes. It gives a ranking theoretic explication of a possible law or a nomological hypothesis. It proves, then, that such schemes of enumerative induction uniquely correspond to mixtures of such nomological hypotheses. Thus, it shows that de Finetti's probabilistic representation theorems may be transformed into an account of confirmation of possible laws and that enumerative induction is equivalent to such an account. The paper concludes with some remarks about the apriority of lawfulness or the uniformity of nature

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.