Johannes Korbmacher
Utrecht University
Papers
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By building on work by Kit Fine, we develop a sound and complete truth- maker semantics for Lou Goble’s conflict tolerant deontic logic BDL.
The Lambda Calculus
I’ve started updating the terrific SEP entry on the lambda calculus by Jesse Alama. The first round of revisions is now online.
I develop a tableau method for the logic of exact entailment described in (Fine and Jago 2017). (Handout.)
Multiple Models, One Explanation
Complex phenomena often require complex explanations. In simple cases, a single model can explain a phenomenon, but fully to explain a complex phenomenon, we often require systems of models. In this paper, we consider how to combine models that differ from each other along multiple lines, for instance, in the way they represent a phenomenon or the variables they include. We provide an interpretation of such situations in terms of structural realism. We focus on the conditions that allow scientists to compare different models so as to combine their results and obtain new knowledge claims.
Elusive Knowledge Hyperintensionalized (Presentation - with Janneke van Lith)
We show how to modify Lewis’s Relevant Alternatives Theory (RAT) to deal with hyperintensional issues, such as knowledge of logic, mathematics, and interesting failures of closure.
Abstract. Informally, structural properties are usually characterized in one of two ways: either as properties expressible purely in terms of the primitive relations of mathematical theories, or as the properties that hold of all structurally similar mathematical objects. In this paper we present two formal explications of structural properties, corresponding to these two informal characterizations. Based on this, we discuss the relation between the two explications. As will be shown, the two characterizations do not determine the same class of mathematical properties. From this observation we draw some philosophical conclusions about the possibility of a “correct” analysis of structural properties.
Axiomatic Theories of Partial Ground II. Partial Ground and Typed Truth
Abstract. This is part two of a two-part paper, in which we develop an axiomatic theory of the relation of partial ground. The main novelty of the paper is the of use of a binary ground predicate rather than an operator to formalize ground. This allows me to connect theories of partial ground with axiomatic theories of truth. In this part of the paper, we extend the base theory from the first part of the paper with hierarchically typed truth-predicates and principles about the interaction of partial ground and truth. We show that our theory is a proof-theoretically conservative extension of the ramified theory of positive truth up to epsilon-naught and thus is consistent. We argue that this theory provides a natural solution to Fine’s “puzzle of ground” about the interaction of truth and ground. Finally, we show that if we drop the typing of our truth-predicate, we run into similar paradoxes as in the case of truth: we get ground-theoretical paradoxes of self-reference.
Axiomatic Theories of Partial Ground I. The Base Theory
Abstract. This is part one of a two-part paper, in which we develop an axiomatic theory of the relation of partial ground. The main novelty of the paper is the of use of a binary ground predicate rather than an operator to formalize ground. This allows us to connect theories of partial ground with axiomatic theories of truth. In this part of the paper, we develop an axiomatization of the relation of partial ground over the truths of arithmetic and show that the theory is a proof-theoretically conservative extension of the theory $PT$ of positive truth. We construct models for the theory and draw some conclusions for the semantics of conceptualist ground.
An Exact Truthmaker Semantics for Permission and Obligation
Abstract. We develop an exact truthmaker semantics for permission and obligation. The idea is that with every singular act, we associate a sphere of permissions and a sphere of requirements: the acts that are rendered permissible and the acts that are rendered required by the act. We propose the following clauses for permissions and obligations:
- a singular act is an exact truthmaker of Pφ iff every exact truthmaker of φ is in the sphere of permissibility of the act, and
- a singular act is an exact truthmaker of Oφ iff some exact truthmaker of φ is in the sphere of requirements of the act.
We show that this semantics is hyperintensional, and that it can deal with some of the so-called paradoxes of deontic logic in a natural way. Finally, we give a sound and complete axiomatization of the semantics.
Yet Another Puzzle of Ground
Abstract. We show that any predicational theory of partial ground that extends a standard theory of syntax and that proves some commonly accepted principles for partial ground is inconsistent. We suggest a way to obtain a consistent predicational theory of ground.