The notion of epistemic coherence is interpreted as involving not only consistency but also stability. The problem how to consolidate a belief system, i.e., revise it so that it becomes coherent, is studied axiomatically as well as in terms of set-theoretical constructions. Representation theorems are given for subtractive consolidation (where coherence is obtained by deleting beliefs) and additive consolidation (where coherence is obtained by adding beliefs).

Hans Rott has argued, most recently in his book Change, Choice and Inference, that certain formal correspondences between belief revision and rational choice have important philosophical implications, claiming that the former strongly indicate the unity of practical and theoretical reason as well as the primacy of practical reason. In this paper, I confront Rott's argument with three serious challenges. My conclusion is that, while Rott's work is indisputable as a formal achievement, the philosophical consequences he wants to draw are not (...) forthcoming. (shrink)

A model of coherentist belief contraction is constructed. The outcome of belief contraction is required to be one of the coherent subsets of the original belief set, and a set of plausible properties is proposed for this set of coherent subsets. The contraction operators obtained in this way are shown to coincide with well-known belief base operations. This connection between coherentist and foundationalist approaches to belief change has important implications for the philosophical interpretation of models of belief change.

This paper argues that formal models of coherence are useful for constructing a legal epistemology. Two main formal approaches to coherence are examined: coherence-based models of belief revision and the theory of coherence as constraint satisfaction. It is shown that these approaches shed light on central aspects of a coherentist legal epistemology, such as the concept of coherence, the dynamics of coherentist justification in law, and the mechanisms whereby coherence may be built in the course of legal decision-making.

According to metaphysical coherentism, grounding relations form an interconnected system in which things ground each other and nothing is ungrounded. This potentially viable view’s logical territory remains largely unexplored. In this paper, I describe that territory by articulating four varieties of metaphysical coherentism. I do not argue for any variety in particular. Rather, I aim to show that not all issues which might be raised against coherentism will be equally problematic for all the versions of that view, which features far (...) more nuance and diversity than is typically ascribed to it. (shrink)

This paper aims at comparing and relating belief revision and argumentation as approaches to model reasoning processes. Referring to some prominent literature references in both fields, we will discuss their (implicit or explicit) assumptions on the modeled processes and hence commonalities and differences in the forms of reasoning they are suitable to deal with. The intended contribution is on one hand assessing the (not fully explored yet) relationships between two lively research fields in the broad area of defeasible reasoning and (...) on the other hand pointing out open issues and potential directions for future research. (shrink)

A general theory of coherence is proposed, in which systemic and relational coherence are shown to be interdefinable. When this theory is applied to sets of sentences, it turns out that logical closure obscures the distinctions that are needed for a meaningful analysis of coherence. It is concluded that references to “all beliefs” in coherentist phrases such as “all beliefs support each other” have to be modified so that merely derived beliefs are excluded. Therefore, in order to avoid absurd conclusions, (...) coherentists have to accept a weak version of epistemic priority, that sorts out merely derived beliefs. Furthermore, it is shown that in belief revision theory, coherence cannot be adequately represented by logical closure, but has to be represented separately. (shrink)

Structural and functional descriptions of technical artefacts play an important role in engineering practice. A complete description of a technical artefact involves a description of both functional and structural features. Engineers, moreover, assume that there is an intimate relationship between the function and structure of technical artefacts and they reason from functional properties to structural ones and vice versa. This raises the question of how structural and functional descriptions are related. The kind of inference patterns that establish coherence between structural (...) and functional descriptions are explored in this paper, using the analysis of coherence creating relations of Thagard et al. Explanatory, analogical and practical inference patterns are discussed and it is argued that of these three, practical inferences may be the most important. Practical inferences, however, cannot provide a full underpinning of the coherence of structural and functional descriptions of technical artefacts. The paper ends with the suggestion that any account of the coherence of the structural and functional descriptions of technical artefacts must involve reference to their intentional features.Keywords: Technical artefact; Structural description; Functional description; Coherence relation; Practical inference. (shrink)

Coherence is a key concept in many accounts of epistemic justification within ‘traditional’ analytic epistemology. Within formal epistemology, too, there is a substantial body of research on coherence measures. However, there has been surprisingly little interaction between the two bodies of literature. The reason is that the existing formal literature on coherence measure operates with a notion of belief system that is very different from—what we argue is—a natural Bayesian formalisation of the concept of belief system from traditional epistemology. Therefore, (...) formal epistemology has so far only been concerned with one particular—arguably not even very natural—way of formalising coherence of belief systems; it has by no means refuted the viability of coherentism. In contrast to the existing literature, we formalise belief systems as families of assignments of (conditional) degrees of belief (which may be compatible with several subjective probability measures). Within this framework, we propose a Bayesian formalisation of the thrust of BonJour’s coherence concept in The structure of empirical knowledge (Harvard University Press, Cambridge, 1985), using a combination of Bayesian confirmation theory and basic graph theory. In excursions, we introduce graded notions for both logical and probabilistic consistency of belief systems—the latter being based on certain geometrical structures induced by probabilistic belief systems. For illustration, we reconsider BonJour’s “ravens” challenge (op. cit., p. 95f.). Finally, potential objections to our proposed formal coherence notion are explored. (shrink)

The 1985 paper by Carlos Alchourrón, Peter Gärdenfors, and David Makinson, “On the Logic of Theory Change: Partial Meet Contraction and Revision Functions” was the starting-point of a large and rapidly growing literature that employs formal models in the investigation of changes in belief states and databases. In this review, the first twenty-five years of this development are summarized. The topics covered include equivalent characterizations of AGM operations, extended representations of the belief states, change operators not included in the original (...) framework, iterated change, applications of the model, its connections with other formal frameworks, computatibility of AGM operations, and criticism of the model. (shrink)

The paper provides a formal representation of goal systems. The focus is on three properties: consistency, conflict, and coherence. An aim is to attain conceptual clarity of these properties. It is argued that consistency is adequately regarded as a property relative to the decision situation or, more specifically, the set of alternatives that the agent faces. Moreover, as a condition of rationality, consistency is stronger than some writers have claimed. Conflict is adequately regarded as a relation over subsets of a (...) given goal system and should likewise be regarded as relative to the set of alternatives that the agent faces. Coherence is given a probabilistic interpretation, based on a support relation over subsets of goal systems. (shrink)

Belief revision theories aim to model the dynamics of epistemic states. Besides beliefs, epistemic states comprise most importantly justificational structures. Typically, belief revision theories, however, model the dynamics of beliefs while neglecting justificational structures over and above logical relations. Despite some awareness that this approach is problematic, how devastating the consequences of this neglect are has not yet been fully grasped. In this paper, I argue that taking justificational structures into account could solve four well-known problems of belief revision.

The thesis aims at developing approaches to transport policy decisions, based on suggestions and ideas originating from moral philosophy and philosophical decision theory. Paper I analyzes the Swedish transport policy goals, and the problem of combining policygoals with welfare economics. A problem of circularity arises as the Swedish transport policygoals are conflicting, and hence must be subject to trade-offs, while several of the goals themselves entail statements on how to prioritize or restrain goals in case of conflict. Paper II analyzes (...) rationality in road safety policy. Problematic features are identified and discussed. The paper argues that the Swedish road safety goal is rational, since it is actionguiding and achievement-inducing. Paper III includes a model of rational choice under risk with biased risk perception. Under certain plausible conditions, a regulator should raise the population’s risk exposure. By deteriorating the environment the regulator can motivate drivers to choose behaviour that is less biased. Paper IV provides a formal representation of goal systems. The focus is on three properties:consistency, conflict, and coherence. It is argued that consistency is adequately regarded as a property relative to the decision situation or, more specifically, the set of alternatives that the agent faces. Conflict is adequately regarded as a relation over subsets of a given goal systemand should likewise be regarded as relative to the set of alternative that the agent faces. Coherence is given a probabilistic interpretation, based on a support relation over subsets of goal systems. Paper V investigates problems associated with standard deontic logic. A deontic predicate is derived, which avoids some of the major paradoxes in the area. In particular, paradoxes occurring when one obligation is derived by logical necessity from another obligation are dealt with. (shrink)