The article argues that there are different ways of justifying suspension of judgement. We suspend judgement not only privatively, that is, because we lack evidence, but also positively, that is, because there is evidence that provides reasons for suspending judgement: suspension is more than the rational fallback position in cases of insufficient evidence. The article applies the distinction to recent discussions about the role of suspension for inquiry, Turri's puzzle about withholding, and formal representations of suspension.

It has recently been argued that some cases of naked statistical evidence license a high credence, but not an outright belief. If this is correct, there cannot be an unconditional bridge principle from credence to outright belief. We show that at least one prominent putative counterexample to such a bridge principle is based on a mistake, by demonstrating that the statistical evidence falls short not only of licensing rational belief, but also of justifying a high credence.

The paper develops an inductive extension of AGM-style belief base revision theory with the aim of formally implementing Freitag’s :254–267, 2015, Dialectica 70:185–200, 2016) solution to Goodman’s paradox. It shows that the paradox dissolves once belief revision takes place on inductively closed belief bases, rather than on belief sets.

The book discusses the central notion of logic, the concept of logical consequence, and its model-theoretic definition as truth-preservation in all models. Whether the model-theoretic definition captures the modal and epistemological features of our pre-theoretic notion depends on what models model. The book argues that, given a non-formal understanding of models, the universal quantifier used in the definition of consequence must be restricted: if literally all models had to be considered, no argument would ever be logically valid. A central challenge (...) of the philosophy of logic is therefore to supplement the model-theoretic definition by a criterion for admissible models. The problem of logical constants, so prominent in the current literature on logical consequence, constitutes but a special case of this much more general demarcation problem. The book explores the various dimensions of the problem of admissible interpretations and proposes that the standard views are unjustified or even unjustifiable. As a consequence, it develops a new vision of logic and suggests in particular that our notion of logical consequence is deeply imbued with metaphysics. (shrink)

The book discusses the central notion of logic: the concept of logical consequence. It shows that the classical definition of consequence as truth preservation in all models must be restricted to all admissible models. The challenge for the philosophy of logic is therefore to supplement the definition with a criterion for admissible models. -/- The problem of logical constants, so prominent in the current debate, constitutes but a special case of this much more general demarcation problem. The book explores the (...) various dimensions of the problem of admissible models and argues that standard responses are unwarranted. As a result, it develops a new vision of logic, suggesting in particular that logic is deeply imbued with metaphysics. (shrink)

We can distinguish two non-equivalent ways in which a natural language argument can be valid: it can be interpretationally or representationally valid. However, there is just one notion of classical first-order validity for formal languages: truth-preservation in all classical first-order models. To ease the tension, Baumgartner suggests that we should understand interpretational and representational validity as imposing different adequacy conditions on formalizations of natural language arguments. I argue against this proposal. To that end, I first show that Baumgartner’s definition of (...) representational validity is extensionally inadequate. I present a number of natural language arguments that we pre-theoretically hold to be representationally valid, but are not representationally valid according to Baumgartner’s definition. I then point to two further untenable features of Baumgartner’s definitions: according to Baumgartner’s definition of a representationally correct formalization, we cannot arrive at formalizations in a recursive way, and Baumgartner’s definition of representational validity is non-monotonic. I conclude that interpretational and representational validity cannot be understood as merely imposing different adequacy conditions on formalizations. If we want to capture our interpretational and representational intuitions, we need two different formal definitions of validity. (shrink)

According to the classical invariance criterion, a term is logical if and only if its extension is isomorphism-invariant. However, a number of authors have devised examples that challenge the sufficiency of this condition: accepting these examples as logical constants would introduce objectionable contingent elements into logic. Recently, Gil Sagi has responded that these objections are based on a fallacious inference from the modal status of a sentence to the modal status of the proposition expressed by that sentence. The present paper (...) demonstrates that Sagi’s response, though successful, is futile. There is another objection, based on the same type of example, that is not susceptible to Sagi’s criticism: accepting the examples as logical terms would have the fatal consequence that any contingent metalanguage sentence is entailed by the truth of some logically true object-language sentence. I conclude with a sketch of an alternative to the classical invariance criterion. (shrink)

We investigate a construction schema for first-order logical systems, called “form logic”. Form logic allows us to overcome the dualistic commitment of predicate logic to individual constants and predicates. Dualism is replaced by a pluralism of terms of different “logical forms”. Individual form-logical systems are generated by the determination of a range of logical forms and of the formbased syntax rules for combining terms into formulas. We develop a generic syntax and semantics for such systems and provide a completeness proof (...) for them. To illustrate the idea of form logic, and the possibilities it facilitates, we discuss three particular systems, one of which is the form-logical reconstruction of standard first-order predicate logic. (shrink)

The paper investigates the prospects of Spohn’s ranking theory with respect to Goodman’s New Riddle of Induction. Based on a novel analysis of the riddle (Freitag [manuscript]), we show it to be an inductive extension of Hansson’s puzzle (Hansson 1992, 1999). As a consequence, a solution needs to take into account the dependence relations between evidential beliefs: “grue” is unprojectible because it depends on evidence whose projection is defeated. It will be suggested that this solution can be implemented into Spohn’s (...) ranking theory, but that ranking theory is unable to provide a proper explanation of the required conditional ranks. (shrink)

This collection includes twenty original philosophical essays in honour of Wolfgang Spohn. The contributions mirror the scope of Wolfgang Spohn’s work. They address topics from epistemology (e.g., the theory of ranking functions, belief revision, and the nature of knowledge and belief), philosophy of science (e.g., causation, induction, and laws of nature), the philosophy of language (e.g., the theory of meaning and the semantics of counterfactuals), and the philosophy of mind (e.g., intentionality and free will), as well as problems of ontology, (...) logic, the theory of practical rationality, and meta-philosophy. ― Contributors: Ansgar Beckermann, Wolfgang Benkewitz, Bernd Buldt, Ralf Busse, Christoph Fehige, Wolfgang Freitag, Gordian Haas, Volker Halbach, Franz Huber, Andreas Kemmerling, Manfred Kupffer, Hannes Leitgeb, Godehard Link, Arthur Merin, Thomas Müller, Julian Nida-Rümelin, Martine Nida-Rümelin, Hans Rott, Holger Sturm, Thomas Ede Zimmermann, Alexandra Zinke. (shrink)

The paper provides a new argument against the classical invariance criterion for logical terms: if all terms with a permutation invariant extension qualify as logical, then for any arbitrary true contingent sentence K of the meta-language, there would be a logically true object-language sentence 'φ' such that K follows from the sentence 'φ is true'. Thus, many logically true sentences would be a posteriori. To prevent this fatal consequence, we propose to alter the invariance criterion: not only the term's extension, (...) but also its semantic clause must satisfy certain invariance conditions. The paper ends with the observation that the new criterion makes explicit the dependency of the classification of terms into logical and non-logical ones at the different levels of the Tarskian hierarchy of languages. (shrink)