This paper extends earlier work by its authors on formal aspects of the processes of contracting a theory to eliminate a proposition and revising a theory to introduce a proposition. In the course of the earlier work, Gardenfors developed general postulates of a more or less equational nature for such processes, whilst Alchourron and Makinson studied the particular case of contraction functions that are maximal, in the sense of yielding a maximal subset of the theory (or alternatively, of one of (...) its axiomatic bases), that fails to imply the proposition being eliminated. In the present paper, the authors study a broader class, including contraction functions that may be less than maximal. Specifically, they investigate "partial meet contraction functions", which are defined to yield the intersection of some nonempty family of maximal subsets of the theory that fail to imply the proposition being eliminated. Basic properties of these functions are established: it is shown in particular that they satisfy the Gardenfors postulates, and moreover that they are sufficiently general to provide a representation theorem for those postulates. Some special classes of partial meet contraction functions, notably those that are "relational" and "transitively relational", are studied in detail, and their connections with certain "supplementary postulates" of Gardenfors investigated, with a further representation theorem established. (shrink)

We show how to construct partial nontrivial base revision operators that satisfy the analogues of the AGM postulates and depends on no extra‐logical consideration. These operators, closely related to the full meet revision process, are defined on stratified bases, in which the information can be ranked in logical sequences. Stratified bases, which can be viewed as sets of graded sheaves, are exactly the knowledge bases for which the full meet revision operator satisfies the rationality (...) postulate K*8. As the revision of a stratified base is again a stratified base, it is possible to perform iterated revisions, and the resulting output is particularly easy to determine. (shrink)

It was shown that finite P-recovery holds for partial meet package contraction in Furhmann and Hansson (1994). However, it is not known if recovery holds for partial meet package contraction in the infinite case. In this paper, I show that recovery does not hold for partial meet package contraction in the infinite case.

Develops a concept of revision, akin in spirit to AGM partial meet revision, but in which the postulate of 'success' may fail. The basic idea is to see such an operation as composite, with a pre-processor using a priori considerations to resolve the question of whether to revise, following which another operation revises in a manner that protects the a priori material.

We look at the problem of revising fuzzy belief bases, i.e., belief base revision in which both formulas in the base as well as revision-input formulas can come attached with varying degrees. Working within a very general framework for fuzzy logic which is able to capture certain types of uncertainty calculi as well as truth-functional fuzzy logics, we show how the idea of rational change from “crisp” base revision, as embodied by the idea of partial (...) class='Hi'>meet (base) revision, can be faithfully extended to revising fuzzy belief bases. We present and axiomatise an operation of partial meet fuzzy base revision and illustrate how the operation works in several important special instances of the framework. We also axiomatise the related operation of partial meet fuzzy base contraction. (shrink)

When an agent can not recognize, immediately, the implausible part of new information received, she will usually first expand her belief state by the new information, and then she may encounter some belief conflicts, and find the implausible information based on her criteria to consolidate her belief state. This process indicates a new kind of non-prioritized multiple revision, called metabolic revision. I give some axiomatic postulates for metabolic revision and propose two functional constructions for it, namely kernel (...) metabolic revision and partial meet metabolic revision, with respect to which the representation theorems are proved. I also compare metabolic revision with some related works in the literature, including semi-revision, merging with integrity constraints, evaluation, and evaluative multiple revision. (shrink)

This paper investigates the formal relationship between two prominent approaches to the logic of belief change. The first one uses the idea of "relational partial meet contractions" as developed by Alchourrón, Gärdenfors and Makinson (Journal of Symbolic Logic 1985), the second one uses the concept of "epistemic entrenchment" as elaborated by Gärdenfors and Makinson (in Theoretical Aspects of Reasoning about Knowledge, M. Y. Vardi, Los Altos 1988). The two approaches are shown to be strictly equivalent via direct links (...) between the underlying formal relations. The paper closes with observations about the application of epistemic entrenchment to simple and iterated revisions. (shrink)

The 1985 paper by Carlos Alchourrón (1931–1996), Peter Gärdenfors, and David Makinson (AGM), "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 twentyfive 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)

Two of the most well-known belief contraction operators are partial meet contractions (PMCs) and kernel contractions (KCs). In this paper we propose two new classes of contraction operators, namely the class of generalized partial meet contractions (GPMC) and the class of generalized kernel contractions (GKC), which strictly contain the classes of PMCs and of KCs, respectively. We identify some extra conditions that can be added to the definitions of GPMCs and of GKCs, which give rise to (...) some interesting subclasses of those classes of functions, namely the classes of extensional and of uniform GPMCs/GKCs. In the context of contractions on belief sets the classes of partial meet contractions, uniform GPMCs and extensional GPMCs are all identical. Nevertheless, when considered as operations on belief bases, the class of uniform GPMCs coincides with the class of partial meet contractions, but the extensional GPMCs constitute a new kind of belief base contraction functions whose characterizing postulate of irrelevance of syntax is extensionality—the same postulate of irrelevance of syntax which occurs in the classical axiomatic characterization of partial meet contractions for belief sets—rather than the postulate of uniformity—which is the irrelevance of syntax postulate used in the axiomatic characterization for partial meet contractions on belief bases. Analogous results are obtained regarding the classes of extensional and of uniform GKCs. We present the interrelations in the sense of inclusion among all the new classes of operators presented in this paper and several well known classes of PMCs and of KCs. (shrink)

An operator of contraction for a belief set (a theory) can be obtained by assigning to it a belief base and an operator of partial meet contraction for that base. It is argued that closure of the base under disjunction is an intuitively reasonable condition. Axiomatic characterizations are given of the contractions of belief sets that can be generated by (various types of) partial meet contraction on disjunctively closed bases. The corresponding revision operators are also (...) characterized. Finally, some results are reported on operations on bases that are closed under material implication. (shrink)

In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb Log 50:510–530, 1985 ). This paper focuses on the extension of AGM that accounts for contractions of a theory by a set of sentences instead of only by a single sentence. Hansson (Theoria 55:114–132, 1989 ), Fuhrmann and Hansson (J Logic Lang Inf 3:39–74, 1994 ) generalized Partial Meet Contraction to the case of contractions by (possibly non-singleton) sets of sentences. (...) In this paper we present the possible worlds semantics for partial meet multiple contractions. (shrink)

We read Adam Smith's Theory of Moral Sentiments as a critical response to David Hume's moral theory. While both share a commitment to moral sentimentalism, they propose different ways of meeting its main challenge, that is, explaining how judgments informed by (partial) sentiments can nevertheless have a justified claim to general authority. This difference is particularly manifest in their respective accounts of ‘moral optics’, or the way they rely on the analogy between perceptual and moral judgments. According to Hume, (...) making perceptual and moral judgments requires focusing on frequently co-occurring impressions (perceptions of objects or reactive sentiments) for tracking an existing object with its perceptual properties or an agent's character traits. Smith uses visual perception for the purpose of illustrating one source of the partiality of the sentiments people feel in response to actions. Before making a moral judgment, people have to disregard this partiality and accept that they are all equally important. Smith and Hume's different ways of relying on the same analogy reveals the still-overlooked and yet profound differences between their moral theories. (shrink)

This paper reorganizes and further develops the theory of partial meet contraction which was introduced in a classic paper by Alchourron, Gardenfors, and Makinson. Our purpose is threefold. First, we put the theory in a broader perspective by decomposing it into two layers which can respectively be treated by the general theory of choice and preference and elementary model theory. Second, we reprove the two main representation theorems of AGM and present two more representation results for the finite (...) case that "lie between" the former, thereby partially answering an open question of AGM. Our method of proof is uniform insofar as it uses only one form of "revealed preference", and it explains where and why the finiteness assumption is needed. Third, as an application, we explore the logic characterizing theory contractions in the finite case which are governed by the structure of simple and prioritized belief bases. (shrink)

By replacement is meant an operation that replaces one sentence by another in a belief set. Replacement can be used as a kind of Sheffer stroke for belief change, since contraction, revision, and expansion can all be defined in terms of it. Replacement can also be defined either in terms of contraction or in terms of revision. Close connections are shown to hold between axioms for replacement and axioms for contraction and revision. Partial meet replacement (...) is axiomatically characterized. It is shown that this operation can have outcomes that are not obtainable through either partial meet contraction or partial meet revision. (shrink)

Modern belief revision theory is based to a large extent on partial meet contraction that was introduced in the seminal article by Carlos Alchourrón, Peter Gärdenfors, and David Makinson that appeared in 1985. In the same year, Alchourrón and Makinson published a significantly different approach to the same problem, called safe contraction. Since then, safe contraction has received much less attention than partial meet contraction. The present paper summarizes the current state of knowledge on safe (...) contraction, provides some new results and offers a list of unsolved problems that are in need of investigation. (shrink)

In the tradition of Stalnaker there is a number of well-known problems that need to be addressed, because revision of iterated belief modalities is required in this case. These problems have already been investigated in detail in recent works on DDL Leitgeb/Segerberg 2007)and DEL see e.g. Ditmarsch et. Another strategy would be to maintain and revise assumptions independently of the beliefs of an agent.I will briefly discuss the advantages and disadvantages of each of these views. In both views, assumptions (...) constitute the subjective context in which an agent interprets an utterance and encounters the world. The result of an interpretation is in turn checked against the agent’s original beliefs, and if the checking operation succeeds the agent revises his beliefs by the result in the normal way described by the AGM paradigm. The second of the above questions needs to be addressed on the basis of concrete examples. Considering utterance like David is ready’ or ‘John is tall’that from a contextualist viewpoint express semantically incomplete content in the sense of Bach is needed in order to obtain a useful model of the checking step, since fortunately not everybody believes everything that other people say. These requirements put the theory of interpretation based on assumptions in the frontline of ongoing research on the implementation of belief revision and update in dynamic logics. Such a theory might also be useful for contextualist accounts of strong knowledge, as it can be argued convincingly that when a knowledge ascription appears to be context-sensitive, this is so because the embedded proposition is context-sensitive and not because knowledge itself is context-sensitive. Hence,the context-sensitivity of embedded propositions in knowledge claims and how different agents in the same situation arrive at different assessments about them may be explained by an inferential theory of interpretation similar to the one outlined here but with another underlying concept of assumptions. Literature Alchourrón, C. E. ; Gärdenfors, P. & Makinson, D., 'On the logic of theory change: partial meet contraction and revision functions', Journal of Symbolic Logic, 510-530. Bach, K., 'Minimalism for Dummies: Reply to Cappelen and Lepore', Technical report, University of San Fransisco, Department of Philosophy. Bach, K., Context ex Machina, in án Gendler Szabó, ed.,'Semantics versus Pragmatics', Oxford UP, Oxford, pp. 16-44. Ditmarsch, H. v. ; Hoek, W. v. d. & Kooi, B., Dynamic Epistemic Logic, Kluwer. Gärdenfors, P., Knowledge in Flux, MIT Press. Leitgeb, H. & Segerberg, K., 'Dynamic doxastic logic: why, how, and where to? ', Synthese155, 167-190. Stalnaker, R., Assertion, in. Cole, ed.,'Pragmatics', Academic Press, New York, pp. 315-332. Stalnaker, R., 'Common Ground', Linguistics and Philosophy25, 701- -721. (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 surveys some recent work on formal aspects of the logic of theory change. It begins with a general discussion of the intuitive processes of contraction and revision of a theory, and of differing strategies for their formal study. Specific work is then described, notably Gärdenfors'' postulates for contraction and revision, maxichoice contraction and revision functions and the condition of orderliness, partial meet contraction and revision functions and the condition of relationality, and finally (...) the operations of safe contraction and revision. Verifications and proofs are omitted, with references given to the literature, but definitions and principal results are presented with rigour, along with discussion of their significance. (shrink)

The paper surveys some recent work on formal aspects of the logic of theory change. It begins with a general discussion of the intuitive processes of contraction and revision of a theory, and of differing strategies for their formal study. Specific work is then described, notably Gärdenfors' postulates for contraction and revision, maxichoice contraction and revision functions and the condition of orderliness, partial meet contraction and revision functions and the condition of relationality, and finally (...) the operations of safe contraction and revision. Verifications and proofs are omitted, with references given to the literature but definitions and principal results are presented with rigour along with discussion of their significance. (shrink)

I reformulate the AGM-account of contraction (which would yield an account also of revision). The reformulation involves using introduction and elimination rules for relational notions. Then I investigate the extent to which the two main methods of partial meet contraction and safe contraction can be employed for theories closed under intuitionistic consequence.

This contribution is a gentle introduction to so-called dynamic epistemic logics, that can describe how agents change their knowledge and beliefs. We start with a concise introduction to epistemic logic, through the example of one, two and finally three players holding cards; and, mainly for the purpose of motivating the dynamics, we also very summarily introduce the concepts of general and common knowledge. We then pay ample attention to the logic of public announcements, wherein agents change their knowledge as the (...) result of public announcements. One crucial topic in that setting is that of unsuccessful updates: formulas that become false when announced. The Moore-sentences that were already extensively discussed at the conception of epistemic logic in Hintikka’s ‘Knowledge and Belief’ give rise to such unsuccessful updates. After that, we present a few examples of more complex epistemic updates. Our closing observations are on recent developments that link the ‘standard’ topic of belief revision, as in ‘On the Logic of Theory Change: partial meet contraction and revision functions’, by Alchourron et al. , to the dynamic epistemic logics introduced here. (shrink)

The principle of compositionality claims that the content of a complex concept is determined by its constituent concepts and the way in which they are composed. However, for prototype concepts this principle is often too rigid. Blurring the division between conceptual composition and belief update has therefore been suggested. Inspired by this idea, we develop a normative account of how belief revision and meaning composition should interact in modifications such as “red apple” or “pet hamster”. We do this by (...) combining the well-known selective modification model :485–527 1988) with the rules of Bayesian belief update. Moreover, we relate this model to systems of defeasible reasoning as discussed in the field of artificial intelligence. (shrink)

This thesis consists in six articles and a comprehensive summary. • The pourpose of the summary is to introduce the AGM theory of belief change and to exemplify the diversity and significance of the research that has been inspired by the AGM article in the last 25 years. The research areas associated with AGM was divided in three parts: criticisms, where we discussed some of the more common criticisms of AGM. Extensions where the most common extensions and variations of AGM (...) are presented and applications where we provided an overview of applications and connections with other areas of research. • Article I elaborates on the connection between partial meet contractions [AGM85] and kernel contractions [Han94a] in belief change theory. Also both functions are equivalent in belief sets, there are notequivalent in belief bases. A way to define incision functions from selection functions and vice versa is presented. It is explained under which conditions there are exact correspondences between selection and incision functions so that the same contraction operations can be obtained by using either of them. • Article II proposes an axiomatic characterization for ensconcement-based contraction functions, belief base functions proposed byWilliams and relates this function with other kinds of base contraction functions. • Article III adapts the Fermé and Hansson model of Shielded Contraction [FH01] as well as Hansson et all Credibility-Limited Revision [HFCF01] for belief bases, to join two of the many variations of the AGM model [AGM85], i.e. those in which knowledge is represented through belief bases instead of logic theories, and those in which the object of the epistemic change does not get the priority over the existing information as it is the case in the AGM model. • Article IV introduces revision by comparison a refined method for changing beliefs by specifying constraints on the relative plausibility of propositions. Like the earlier belief revision models, the method proposed is a qualitative one, in the sense that no numbers are needed in order to specify the posterior plausibility of the new information. The method uses reference beliefs in order to determine the degree of entrenchment of the newly accepted piece of information. Two kinds of semantics for this idea are proposed and a logical characterization of the new model is given. • Article V focuses on the extension of AGM that allows change for a belief base by a set of sentences instead of a single sentence. In [FH94], Fuhrmann and Hansson presented an axiomatic for Multiple Contraction and a construction based on the AGM Partial Meet Contraction. This essay proposes for their model another way to construct functions: Multiple Kernel Contraction, that is a modification of Kernel Contraction,proposed by Hansson [Han94a] to construct classical AGM contractions and belief base contractions. • Article VI relates AGM model with the DFT model proposed by Carlos Alchourrón [Alc93]. Alchourrón devoted his last years to the analysis of the notion of defeasible conditionalization. His definition of the defeasible conditional is given in terms of strict implication operator and a modal operator f which is interpreted as a revision function at the language level. This essay points out that this underlying revision function is more general than AGM revision. In addition, a complete characterization of that more general kind of revision that permits to unify models of revision given by other authors is given. (shrink)

The AGM theory of belief revision provides a formal framework to represent the dynamics of epistemic states. In this framework, the beliefs of the agent are usually represented as logical formulas while the change operations are constrained by rationality postulates. In the original proposal, the logic underlying the reasoning was supposed to be supraclassical, among other properties. In this paper, we present some of the existing work in adapting the AGM theory for non-classical logics and discuss their interconnections and (...) what is still missing for each approach. (shrink)

In this article we explore multiple change operators, i.e., operators in which the epistemic input is a set of sentences instead of a single sentence. We propose two types of change: prioritized change, in which the input set is fully accepted, and symmetric change, where both the epistemic state and the epistemic input are equally treated. In both kinds of operators we propose a set of postulates and we present different constructions: kernel changes and partial meet changes.

Specified meet contraction is the operation defined by the identity where ∼ is full meet contraction and f is a sentential selector, a function from sentences to sentences. With suitable conditions on the sentential selector, specified meet contraction coincides with the partial meet contractions that yield a finite-based contraction outcome if the original belief set is finite-based. In terms of cognitive realism, specified meet contraction has an advantage over partial meet contraction in (...) that the selection mechanism operates on sentences rather than on temporary infinite structures (remainders) that are cognitively inaccessible. Specified meet contraction provides a versatile framework in which other types of contraction, such as severe withdrawal and base-generated contraction, can be expressed with suitably chosen properties of the sentential selector. (shrink)

Ethical theories normally make room both for global duties to human beings everywhere and special duties to those we are attached to in some way. Such a split-level view requires us to specify the kind of attachment that can ground special duties, and to explain the comparative force of the two kinds of duties in cases of conflict. Special duties are generated within groups that are intrinsically valuable and not inherently unjust, where the duties can be shown to be integral (...) to relationships within the group. Since nations can be shown to meet these conditions, acknowledging special obligations towards compatriots is justified. However for such partiality to be reasonable, it must be balanced against recognition of duties of global justice. These duties include duties to respect human rights and duties of fairness towards non-nationals. Weighing such duties against domestic duties of social justice is not a simple task, and the outcome should depend on the precise specification of the duty at stake. In particular, the duty to respect human rights fragments into four sub-duties whose force when set against local duties is markedly different. (shrink)

Choice revision is a sort of non-prioritized multiple revision, in which the agent partially accepts the new information represented by a set of sentences. We investigate the construction of choice revision based on a new approach to belief change called descriptor revision. We prove that each of two variants of choice revision based on such construction is axiomatically characterized with a set of plausible postulates, assuming that the object language is finite. Furthermore, we introduce an (...) alternative modelling for choice revision, which is based on a type of relation on sets of sentences, named multiple believability relation. We show without assuming a finite language that choice revision constructed from such relations is axiomatically characterized with the same sets of postulates that we proposed for the choice revision based on descriptor revision, whenever the relations satisfy certain rationality conditions. (shrink)

Philosophers and scientists have maintained that causation, correlation, and partial correlation are essentially related. These views give rise to various rules of causal inference. This essay considers the claims of several philosophers and social scientists for causal systems with dichotomous variables. In section 2 important commonalities and differences are explicated among four major conceptions of correlation. In section 3 it is argued that whether correlation can serve as a measure of A's causal influence on B depends upon the conception (...) of causation being used and upon certain background assumptions. In section 4 five major kinds of partial correlation are explicated, and some of the important relations are established among two conceptions of partial correlation, the conception of screening off, the conception of partitioning, and the measures of causal influence which have been suggested by advocates of path analysis or structural equation methods. In section 5 it is argued that whether any of these five conceptions of partial correlation can serve as a measure of causal influence depends upon the conception of causation being used and upon certain background assumptions.The important conclusion is that each of the approaches (considered here) to causal inference for causal systems with dichotomous variables stands in need of important qualifications and revisions if they are to be justified. (shrink)

The problem of future contingents is regarded as an important philosophical problem in connection with determinism and it should be treated by tense logic. Prior’s early work focused on the problem, and later Prior studied branching-time tense logic which was invented by Kripke. However, Prior’s idea to use three-valued logic for the problem seems to be still alive. In this paper, we consider partial and paraconsistent approaches to the problem of future contingents. These approaches theoretically meet Aristotle’s interpretation (...) of future contingents. (shrink)

Theories of moral desert focus only on the personal culpability of the agent to determine the amount of blame and punishment the agent deserves. I defend an alternative account of desert, one that does not focus only facts about offenders and their offenses. In this revised framework, personal culpability can do no more than set upper and lower limits for deserved blame and punishment. For more precise judgments within that spectrum, additional factors must be considered, factors that are independent of (...) the agent and the offense. I refer to this as the ‘partial conception’ of desert because takes facts about victims—their behavior, desires, and attitudes—into account for desert judgments. On my view, then, agents who are equally culpable may deserve different amounts of blame or punishment, depending on these victim-related factors. (shrink)

In a recent article, Krauss (2017) raises some fundamental questions concerning (i) what the desiderata of a definition of lying are, and (ii) how definitions of lying can account for partial beliefs. This paper aims to provide an adequate answer to both questions. Regarding (i), it shows that there can be a tension between two desiderata for a definition of lying: 'descriptive accuracy' (meeting intuitions about our ordinary concept of lying), and 'moral import' (meeting intuitions about what is wrong (...) with lying), vindicating the primacy of the former desideratum. Regarding (ii), it shows that Krauss' proposed 'worse-off requirement' meets neither of these desiderata, whereas the 'comparative insincerity condition' (Marsili 2014) can meet both. The conclusion is that lies are assertions that the speaker takes to be more likely to be false than true, and their distinctive blameworthiness is a function of the extent to which they violate a sincerity norm. (shrink)

The paper deals with partiality flowing from special relationships. Two main problems are discussed. The first concerns the relationship between partiality and genuine moral obligations. If partiality can bring about such obligations only if it is reasonable, what requirements should it meet in order to be reasonable? The second problem is one of animal ethics. Can the concept of reasonable partiality help us articulate what is morally at stake in a current discussion about the treatment of domestic animals, viz. (...) the European discussion about the castration of pigs? (shrink)

To the normal reasons that we think can justify one in preferring something, x (namely, that x has objectively preferable properties, or has properties that one prefers things to have, or that x's obtaining would advance one's preferences), I argue that it can be a justifying reason to prefer x that one's very preferring of x would advance one's preferences. Here, one prefers x not because of the properties of x, but because of the properties of one's having the preference (...) for x. So-revising one's preferences is rational in paradoxical choice situations like Kavka's Deterrence Paradox. I then try to meet the following objections: that this is stoicist, incoherent, bad faith; that it conflates instrumental and intrinsic value, gives wrong solutions to the problems presented by paradoxical choice situations, entails vicious regresses of value justification, falsifies value realism, makes valuing x unresponsive to x's properties, causes value conflict, conflicts with other standards of rationality, violates decision theory, counsels immorality, makes moral paradox, treats value change as voluntary, conflates first- and second-order values, is psychologically unrealistic, and wrongly presumes that paradoxical choice situations can even occur. (shrink)

We introduce two new belief revision axioms: partial monotonicity and consequence correctness. We show that partial monotonicity is consistent with but independent of the full set of axioms for a Gärdenfors belief revision sytem. In contrast to the Gärdenfors inconsistency results for certain monotonicity principles, we use partial monotonicity to inform a consistent formalization of the Ramsey test within a belief revision system extended by a conditional operator. We take this to be a technical (...) dissolution of the well-known Gärdenfors dilemma.In addition, we present the consequential correctness axiom as a new measure of minimal revision in terms of the deductive core of a proposition whose support we wish to excise. We survey several syntactic and semantic belief revision systems and evaluate them according to both the Gärdenfors axioms and our new axioms. Furthermore, our algebraic characterization of semantic revision systems provides a useful technical device for analysis and comparison, which we illustrate with several new proofs. (shrink)

Hartry Field, Jerry Fodor and others differ with Donald Davidson over the question of how a theory of content should be structured. Field and Fodor maintain that a theory should begin by following the compositional structure of a sentence in reducing the semantic properties of complex expressions to the semantic properties of their simplest parts and complete the job by reducing the semantic properties of the parts to non-semantic ones. Davidson describes this approach as the ‘Building-Block method’ and maintains that (...) it cannot possibly succeed. He holds that a theory of content should ‘give up reference’ by treating the semantic properties of basic expressions as a purely technical devices with no direct relation to non-semantic phenomenon. In this essay, I examine what I call “Davidson’s Dilemma”, the conflict between the apparent soundness the arguments for the view that a theory must treat reference as a point where linguistic and non-linguistic reality meet and the equally apparent soundness his argument that reference cannot possibly play this role. I propose a resolution to the dilemma that grants the validity of Davidson’s arguments against the building-block theories but is, I believe, more palatable to mainstream semanticists than Davidson’s solution. This solution, which I call ‘content partialism’ treats the reference of terms as regularities across propositional contents. I show how content partialism is consistent with a Kripkean theory of reference fixing, the touchstone of those who advocate building-block theories. (shrink)

1. There is no dearth of objections to Rawls's A Theory of justice. Scores of articles and several books begin by praising the rigor and depth of Rawls's book — and end by concluding that it is thoroughly mistaken. In the present essay I will not add to the list of negative responses to A Theory of Justice. Instead I will attempt to reply to Rawls's critics in a way which makes a positive contribution to his theory.2. Among the many (...) objections that have been raised against Rawls's theory, two are of paramount importance. It is these two objections I shall attempt to meet. They may be formulated as follows. (shrink)

Philosophers and scientists have maintained that causation, correlation, and "partial correlation" are essentially related. These views give rise to various rules of causal inference. This essay considers the "claims of several philosophers and social scientists for causal systems with dichotomous variables. In section 2 important commonalities and differences are explicated among four major conceptions of correlation. In section 3 it is argued that whether correlation can serve as a measure of A's causal influence on B depends upon the conception (...) of causation being used and upon certain background assumptions. In section 4 five major kinds of "partial correlation" are explicated, and some of the important relations are established among two conceptions of "partial correlation", the conception of "screening off", the conception of "partitioning", and the measures of causal influence which have been suggested by advocates of path analysis or structural equation methods. In section 5 it is argued that whether any of these five conceptions of "partial correlation" can serve as a measure of causal influence depends upon the conception of causation being used and upon certain background assumptions. The important conclusion is that each of the approaches (considered here) to causal inference for causal systems with dichotomous variables stands in need of important qualifications and revisions if they are to be justified. (shrink)

The rational status of the Bayesian calculus for revising likelihoods is compromised by the common but still unfamiliar phenomenon of information distortion. This bias is the distortion in the evaluation of a new datum toward favoring the currently preferred option in a decision or judgment. While the Bayesian calculus requires the independent combination of the prior probability and a new datum, information distortion invalidates such independence (because the prior influences the datum). Although widespread, information distortion has not generally been recognized. (...) First, individuals are not aware when they themselves commit this bias. In addition, it is often hidden in more obvious suboptimal phenomena. Finally, the Bayesian calculus is usually explained only with undistortable data like colored balls drawn randomly. Partly because information distortion is unrecognized by the individuals exhibiting it, no way has been devised for eliminating it. Partial reduction is possible in some situation such as presenting all data simultaneously rather than sequentially with revision after each datum. The potential dangers of information distortion are illustrated for three professional revision tasks: forecasting, predicting consumer choices from internet data, and statistical inference from experimental results. The optimality of the Bayesian calculus competes with people’s natural desire that their belief systems remain coherent in the face of new data. Information distortion provides this coherence by biasing those data toward greater agreement with the currently preferred position – but at the cost of Bayesian optimality. (shrink)

In the light of growing political and religious fundamentalism, this open access book defends the idea of freedom as paramount for the attempt to find common ethical ground in the age of globality. The book sets out to examine as yet unexhausted ways to boost the resilience of the principle of liberalism. Critically reviewing the last 200 years of the philosophy of freedom, it revises the principle of liberty in order to revive it. It discusses many different aspects that fall (...) under its three main topics: the metaphysics of freedom, quantitative freedom and qualitative freedom. Open societies worldwide have come under increasing pressure in the last decades. The belief that politics and markets fare best when guided by the principle of liberty presently faces multiple challenges such as terrorism, climate warming, inequality, populism, and financial crises. In the view of its critics, the idea of freedom no longer offers adequate guidance to meet these challenges and should be partially corrected or even entirely replaced by countervailing values. Against the reduction of freedom to the merely quantitative question as to how much liberties individuals call their own, this book draws attention to the qualitative concerns which and whose opportunities society should foster. It argues that, correctly understood, the idea of liberty commits us to defend as well as advance the freedom of each and every world citizen. (shrink)

Presentism is, roughly, the metaphysical doctrine that maintains that whatever exists, exists in the present. The compatibility of presentism with the theories of special and general relativity was much debated in recent years. It has been argued that at least some versions of presentism are consistent with time-orientable models of general relativity. In this paper we confront the thesis of presentism with relativistic physics, in the strong gravitational limit where black holes are formed. We conclude that the presentist position is (...) at odds with the existence of black holes and other compact objects in the universe. A revision of the thesis is necessary, if it is intended to be consistent with the current scientific view of the universe. (shrink)

Shortened and mildly revised version of an essay that initially appeared in Murove (ed.) African Ethics (2009). This chapter is a work of applied ethics that aims to provide a convincing comprehensive account of how a government official in a post-independence sub-Saharan country should make decisions about how to allocate goods such as civil service jobs and contracts with private firms. Should such a person refrain from considering any particulars about potential recipients, or might it be appropriate to consider, for (...) example, family membership, party affiliation, race, or revolutionary stature as reasons to benefit certain individuals at some cost to the public? Which of these factors should be considered an unjust or corrupt basis on which to allocate state goods and which should not? Drawing on an African ethic, this chapter answers these questions with what it calls a “moderate partialism,” according to which a government agent may rightly favor at some cost to the public veterans and victims of state injustices, but not those in her family or party. This chapter seeks to provide a new, unified explanation of why characteristically sub-Saharan values permit some forms of partiality, such as the preferential hiring of those who suffered from or struggled against colonialism, but forbid other, nepotist or prebendalist forms of partiality. (shrink)