In this paper, I examine the possibility of accounting for the rationality of belief-formation by utilising decision-theoretic considerations. I consider the utilities to be used by such an approach, propose to employ verisimilitude as a measure of cognitive utility, and suggest a natural way of generalising any measure of verisimilitude defined on propositions to partial belief-systems, a generalisation which may enable us to incorporate Popper's insightful notion of verisimilitude within a Bayesian framework. I examine a dilemma generated by the decision-theoretic (...) procedure and consider an adequacy condition (immodesty) designed to ameliorate one of its horns. Finally, I argue in a sceptical vein that no adequate verisimilitude measure can be used decision-theoretically. (shrink)

Conditional logics have traditionally been intended to formalize various intuitively correct modes of reasoning involving conditional expressions in natural language. Although conditional logics have by now been thoroughly studied in a classical context, they have yet to be systematically examined in an intuitionistic context, despite compelling philosophical and technical reasons to do so. This paper addresses this gap by thoroughly examining the basic intuitionistic conditional logic ICK, the intuitionistic counterpart of Chellas’ important classical system CK. I give ICK both worlds (...) semantics and algebraic semantics, and prove that these are equivalent. I give a Gödel-type embedding of ICK into CK and a Glivenko-type embedding of CK into ICK. I axiomatize ICK and prove soundness, completeness, and decidability results. Finally, I discuss extending ICK. (shrink)

The purpose of the present paper is to challenge some received assumptions about the logical analysis of modal English, and to show that these assumptions are crucial to certain debates in current philosophy of language. Specifically, I will argue that the standard analysis in terms of quantified modal logic mistakenly fudges important grammatical distinctions, and that the validity of Kripke's modal argument against description theories of proper names crucially depends on ensuing equivocations.

Every kind of ‘ought’ implies some kind of ‘can’ – but there are many kinds of ‘ought’ and even more kinds of ‘can’. In this essay, I shall focus on a particular kind of ‘ought’ – specifically, on what I shall call the “rational ‘ought’”. On every occasion of use, this kind of ‘ought’ is focused on the situation of a particular agent at a particular time; but this kind of ‘ought’ is concerned, not with how that agent acts at (...) that time, but with what beliefs or intentions the agent has at the time, or with the sort of reasoning by means of which the agent at that time forms or revises those beliefs or intentions. (shrink)

This essay defends a version of the Doctrine of Double Effect (DDE) – the doctrine that there is normally a stronger reason against an act that has a bad state of affairs as one of its intended effects than against an otherwise similar act that has that bad state of affairs as an unintended effect. First, a precise account of this version of the DDE is given. Secondly, some suggestions are made about why we should believe the DDE, and about (...) why it is true. Finally, a solution is developed to the so-called ‘closeness problem’ that any version of the DDE must face. (shrink)

I argue that the best interpretation of the general theory of relativity has need of a causal entity, and causal structure that is not reducible to light cone structure. I suggest that this causal interpretation of GTR helps defeat a key premise in one of the most popular arguments for causal reductionism, viz., the argument from physics.

Humeanism is “the thesis that the whole truth about a world like ours supervenes on the spatiotemporal distribution of local qualities.” (Lewis, 1994, 473) Since the whole truth about our world contains truths about causation, causation must be located in the mosaic of local qualities that the Humean says constitute the whole truth about the world. The most natural ways to do this involve causation being in some sense extrinsic. To take the simplest possible Humean analysis, we might say that (...) c causes e iff throughout the mosaic events of the same type as c are usually followed by events of type e. For short, the causal relation is the constant conjunction relation. Whether this obtains is determined by the mosaic, so this is a Humean theory, but it isn’t determined just by c and e themselves, so whether c causes e is extrinsic to the pair. Now this is obviously a bad theory of causation, but the fact that causation is extrinsic is retained even by good Humean theories of causation. John Hawthorne (2004) objects to this feature of Humeanism. I’m going to argue that his arguments don’t work, but first we need to clear up three preliminaries about causation and intrinsicness. (shrink)

I show how Sir William Rowan Hamilton’s philosophical commitments led him to a causal interpretation of classical mechanics. I argue that Hamilton’s metaphysics of causation was injected into his dynamics by way of a causal interpretation of force. I then detail how forces are indispensable to both Hamilton’s formulation of classical mechanics and what we now call Hamiltonian mechanics (i.e., the modern formulation). On this point, my efforts primarily consist of showing that the contemporary orthodox interpretation of potential energy is (...) the interpretation found in Hamilton’s work. Hamilton called the potential energy function the “force-function” because he believed that it represents forces at work in the world. Various non-historical arguments for this orthodox interpretation of potential energy are provided, and matters are concluded by showing that in classical Hamiltonian mechanics, facts about the potential energies of systems are grounded in facts about forces. Thus, if one can tolerate the view that forces are causes of motion, then Hamilton provides one with a road map for transporting causation into one of the most mathematically sophisticated formulations of classical mechanics, viz., Hamiltonian mechanics. (shrink)

This paper presents a new theory of the truth conditions for indicative conditionals. The theory allows us to give a fairly unified account of the semantics for indicative and subjunctive conditionals, though there remains a distinction between the two classes. Put simply, the idea behind the theory is that the distinction between the indicative and the subjunctive parallels the distinction between the necessary and the a priori. Since that distinction is best understood formally using the resources of two-dimensional modal logic, (...) those resources will be brought to bear on the logic of conditionals. (shrink)

I show that the existence of an omniscient, omnipotent, and essentially omnimalevolent being is impossible given only two metaethical assumptions (viz., moral rationalism and reasons internalism). I then argue (pace Stephen Law) that such an impossibility undercuts Law’s (Relig Stud 46(3):353–373, 2010) evil god challenge.

I set out and defend a view on indicative conditionals that I call “indexical relativism ”. The core of the view is that which proposition is expressed by an utterance of a conditional is a function of the speaker’s context and the assessor’s context. This implies a kind of relativism, namely that a single utterance may be correctly assessed as true by one assessor and false by another.

David Lewis has long defended an analysis of counterfactuals in terms of comparative similarity of possible worlds. The purpose of this paper is to reevaluate Lewis’s response to one of the oldest and most familiar objections to this proposal, the future similarity objection.

A novel motivation for a Humean projectivist construal of our concept of scientific law is provided. The analysis is partially developed and used to explain intuitions that are problematic for a Humean reductionist construal of lawhood. A possible non-Humean rejoinder is discussed and rejected. In an appendix, further intuitions that are problematic for Humean reductionists are explained projectively.

Advocates and opponents of Humean Supervenience (HS) have neglected a crucial feature of nomic explanation: laws can explain by generating descriptions of possibilities. Dretske and Armstrong have opposed HS by arguing that laws construed as Humean regularities cannot explain, but their arguments fail precisely because they neglect to consider this generating role of laws. Humeans have dismissed the intuitive violations of HS manifested by John Carroll's Mirror Worlds as erroneous, but distinguishing the laws' generating role from the non-Humean notion that (...) laws govern undermines such responses, and renews the force of Carroll's critique of HS. However, it also undermines the assumption that HS is constitutive of Humeanism. The generating role of laws readily motivates a non-reductive Humeanism that violates HS. An account is sketched, and is seen to provide a novel explanation of the governing intuition. (shrink)

This paper formulates a general epistemological argument against what I call non-causal realism, generalizing domain specific arguments by Benacerraf, Field, and others. First I lay out the background to the argument, making a number of distinctions that are sometimes missed in discussions of epistemological arguments against realism. Then I define the target of the argument—non-causal realism—and argue that any non-causal realist theory, no matter the subject matter, cannot be given a reasonable epistemology and so should be rejected. Finally I discuss (...) and respond to several possible responses to the argument. In addition to clearing up and avoiding numerous misunderstandings of arguments of this kind that are quite common in the literature, this paper aims to present and endorse a rigorous and fully general epistemological argument against realism. (shrink)

It is argued thatde dicto andde re beliefs are attitudes towards syntactically structured entities (sentences) in the head. In order to identify the content of ade dicto orde re belief, we must be able to match causal relations of belief states to natural language inferences. Such match-ups provide sufficient empirical justification for regarding those causal relations as syntactic transformations, that is, inferences. But only syntactically structured entities are capable of enjoying such inferential relations. Hence,de dicto andde re beliefs must be (...) syntactically structured. Given that beliefs are also brain states, it follows that they are sentences in the brain. The argument presented here is shown to be an improvement over similar arguments advanced by Harman and Fodor. (shrink)

Language theorists have recently come to have an increasing appreciation for the fact that context contributes heavily in determining our interpretation of what is said. Indeed, it now seems clear that no complete understanding of a natural language is possible without some account of the way in which context affects our interpretation of discourse. In this paper, I will attempt to explore one facet of the language – context relationship, namely, the relation between conditionals and context. The first part of (...) the paper develops an account of truth for conditionals which allows them to depend on momentary features of the context in which they are uttered. In the second half of the paper, comparisons with other recent theories of the conditional will be considered. Particular attention will be given to the problem of whether the conditional really violates classical inferences such as Hypothetical Syllogism and Contraposition as has often been claimed in recent years. (shrink)

Disagreeing with most authors on vagueness, the author proposes a solution that he calls ‘three-valued semantic pluralism’ to the age-old sorites paradox. In essence, it is a three-valued semantics for a first-order vague language with identity with the additional suggestion that a vague language has more than one correct interpretation. Unlike the traditional three-valued approach to a vague language, three-valued semantic pluralism can accommodate the phenomenon of higher-order vagueness and the phenomenon of penumbral connection when equipped with ‘suitable conditionals’. The (...) author also shows that three-valued semantic pluralism is a natural consequence of a restricted form of the Tolerance principle ) and a few related ideas, and argues that ) is well-motivated by considerations about how we learn, teach, and use vague predicates. (shrink)

For a putative knower S and a proposition P , two types of skepticism can be distinguished, depending on the conclusions they draw: outer skepticism , which concludes that S does not know that P , and inner skepticism , which concludes that S does not know whether P . This paper begins by showing that outer skepticism has undesirable consequences because that S does not know that P presupposes P , and inner skepticism does not have this undesirable consequence (...) since that S does not know whether P does not presuppose P . We indicate that the two types of skepticism aim to different loci of doubts: while outer skepticism doubts whether we can gain an epistemic warrant for the actuality, inner skepticism doubts whether we can gain epistemic identification of the actuality. It is further indicated that responses to skepticism from externalist theories, as well as from fallibilist internalist theories, can only respond to outer skepticism but not to inner skepticism. (shrink)

Comparative syllogism is a type of scientific reasoning widely used, explicitly or implicitly, for inferences from observations to conclusions about effectiveness, but its philosophical significance has not been fully elaborated or appreciated. In its simplest form, the comparative syllogism derives a conclusion about the effectiveness of a factor (e.g. a treatment or an exposure) on a certain property via an experiment design using a test (experimental) group and a comparison (control) group. Our objective is to show that the comparative syllogism (...) can be understood as encoding a simulation view of counterfactuals, in that counterfactual situations are conceptual constructs that can be correctly simulated by homogeneous comparison groups. In this simulation view, the empirical data from the comparison groups play an evidential role in the evaluation of counterfactuals and in obtaining counterfactual knowledge. We further indicate how successful experimental designs can help us to obtain correct simulations, and thus to bring us to scientifically-empirically based counterfactual knowledge. (shrink)

While epiphenomenalism—i.e., the claim that the mental is a causally otiose byproduct of physical processes that does not itself cause anything—is hardly ever mentioned in philosophical discussions of free will, it has recently come to play a crucial role in the scientific attack on free will led by neuroscientists and psychologists. This paper is concerned with the connection between epiphenomenalism and the claim that free will is an illusion, in particular with the connection between epiphenomenalism and willusionism, i.e., with the (...) thesis that there is empirical evidence for a thoroughgoing skepticism with regard to free will that is based on the claim that mental states are epiphenomena. The paper discusses four arguments for willusionism that in some form or other appeal to epiphenomenalism and argues that three of them can be discarded relatively easily. The fourth one, based on Daniel Wegner’s theory of apparent mental causation and his claim that free will is an illusion because the feeling of conscious will is epiphenomenal with regard to the corresponding voluntary actions, is dealt with in more detail. The overall verdict is negative: there is no empirical evidence for any kind of epiphenomenalism that would warrant the claim that free will is an illusion. Whatever it is that makes free will the object of contention between neuroscience and philosophy, epiphenomenalism provides no reason to think that free will is an illusion. (shrink)

Is A & C sufficient for the truth of ‘if A were the case, C would be the case’? Jonathan Bennett thinks not, although the counterexample he gives is inconsistent with his own account of counterfactuals. In any case, I argue that anyone who accepts the case of Morgenbesser's coin, as Bennett does, should reject Bennett’s counterexample. Moreover, I show that the principle underlying his counterexample is unmotivated and indeed false. More generally, I argue that Morgenbesser’s coin commits us to (...) the sufficiency of A & C for the truth of the corresponding counterfactual. (shrink)

The debate over Hypothetical Syllogism is locked in stalemate. Although putative natural language counterexamples to Hypothetical Syllogism abound, many philosophers defend Hypothetical Syllogism, arguing that the alleged counterexamples involve an illicit shift in context. The proper lesson to draw from the putative counterexamples, they argue, is that natural language conditionals are context-sensitive conditionals which obey Hypothetical Syllogism. In order to make progress on the issue, I consider and improve upon Morreau’s proof of the invalidity of Hypothetical Syllogism. The improved proof (...) relies upon the semantic claim that conditionals with antecedents irrelevant to the obtaining of an already true consequent are themselves true. Moreover, this semantic insight allows us to provide compelling counterexamples to Hypothetical Syllogism that are resistant to the usual contextualist response. (shrink)

Kadri Vihvelin, in "What time travelers cannot do" (Philos Stud 81: 315-330, 1996), argued that "no time traveler can kill the baby who in fact is her younger self, because (V1) "if someone would fail to do something, no matter how hard or how many times she tried, then she cannot do it", and (V2) if a time traveler tried to kill her baby self, she would always fail. Theodore Sider (Philos Stud 110: 115-138, 2002) criticized Vihvelin's argument, and Ira (...) Kiourti (Philos Stud 139: 343-352, 2008) criticized both Vihvelin's argument and Sider's critique. I present a critique of Vihvelin's argument different from both Sider's and Kiourti's critiques: I argue in a novel way that both V1 and V2 are false. Since Vihvelin's argument might be understood as providing a challenge to the possibility of time travel, if my critique succeeds then time travel survives such a challenge unscathed. (shrink)

I defend the following version of the ought-implies-can principle: (OIC) by virtue of conceptual necessity, an agent at a given time has an (objective, pro tanto) obligation to do only what the agent at that time has the ability and opportunity to do. In short, obligations correspond to ability plus opportunity. My argument has three premises: (1) obligations correspond to reasons for action; (2) reasons for action correspond to potential actions; (3) potential actions correspond to ability plus opportunity. In the (...) bulk of the paper I address six objections to OIC: three objections based on putative counterexamples, and three objections based on arguments to the effect that OIC conflicts with the is/ought thesis, the possibility of hard determinism, and the denial of the Principle of Alternate Possibilities. (shrink)

As cause we often specify an event the occurrence of which first guaranteed that of the effect. This notion is explicated in a framework of branching worlds in Sections I to V. VI and VII point out its close relations to the concept of an agent's bringing about an event. The topic of the last two sections is the distinction between causes and necessary circumstances. For this purpose conditionals are used, interpreted with respect to branching worlds without a similarity relation (...) between them. (shrink)

Recently, various people have maintained that one must revise either the externalistically-based notion of singular thought or the naïve realism-inspired notion of relational particularity, as respectively applied to some thoughts and to some perceptual experiences. In order to do so, one must either provide a broader notion of singular thought or flank the notion of relational particularity with a broader notion of phenomenal particularity. I want to hold that there is no need of that revision. For the original notions can (...) still play the role for which they were invoked. This requires that (i) both the first and the second notion respectively involve a dependence on and a metaphysical relation to the intentional objects of certain mental states once we are ontologically committed to such objects; (ii) both that object-dependence and that metaphysical relation are interpreted in terms of a substantive individuation of the relevant mental state via the object it is about: that object constitutes the state. (shrink)

In recent years, the notion of a reason has come to occupy a central place in both metaethics and normative theory more broadly. Indeed, many philosophers have come to view reasons as providing the basis of normativity itself . The common conception is that reasons are facts that count in favor of some act or attitude. More recently, philosophers have begun to appreciate a distinction between objective and subjective reasons, where (roughly) objective reasons are determined by the facts, while subjective (...) reasons are determined by one's beliefs. My goal in this paper is to offer a plausible theory of subjective reasons. Although much attention has been focused on theories of objective reasons, very little has been offered in the literature regarding what sort of account of subjective reasons we should adopt; and what has been offered is rather perfunctory, and requires filling-out. Taking what has been said thus far as a starting point, I will consider several putative theories of subjective reasons, offering objections and amendments along the way, will settle on what I take to be a highly plausible account, and will defend that account against objections. (shrink)

McCall (1984) offered a semantics of counterfactual conditionals based on “real possible worlds” that avoids using the vague notion of similarity between possible worlds. I will propose an interpretation of McCall’s counterfactuals in a formal framework based on Baltag-Moss-Solecki events and protocols. Moreover, I will argue that using this interpretation one can avoid an objection raised by Otte (1987).

In Spanish (and other Romance languages) certain predicates select the subjunctive mood in the embedded clause, while others select the indicative mood. In this paper, I present a new analysis for the predicates that select the subjunctive mood in Spanish that is based on a semantics of comparison. The main generalization proposed here is the following: in Spanish, a predicate selects the subjunctive mood in its embedded proposition if the proposition is compared to its contextual alternatives on a scale introduced (...) by the predicate. In this proposal, predicates that select the subjunctive mood are thus analyzed as gradable predicates. Furthermore, the subjunctive mood morpheme is claimed to make a semantic contribution, namely to evaluate the contextual alternatives that are compared by the predicate. In comparing this proposal to other approaches, I show that it can more straightforwardly account for a number of properties of these predicates (entailment relations, practical inferences, and contexts with more than two alternatives). New empirical evidence for two crucial properties of the predicates that select the subjunctive mood is provided: these predicates are focus sensitive and they are gradable, two properties that follow directly from the proposal developed here. In the vast literature on mood, the link between the appearance of the subjunctive mood and these important properties has never been made before. (shrink)

It’s often claimed in the philosophical and scientific literature on temporal representation that there is no such thing as a genuine sensory system for time. In this paper, I argue for the opposite—many animals, including all mammals, possess a genuine sensory system for time based in the circadian system. In arguing for this conclusion, I develop a semantics and meta-semantics for explaining how the endogenous rhythms of the circadian system provide organisms with a direct information link to the temporal structure (...) of their environment. In doing so, I highlight the role of sensory systems in an information processing architecture. (shrink)

In this paper, I stress the utility of employing test-driven development (TDD) for conceiving logical systems. TDD, originally invented in the context of Extreme Programming, is a methodology widely used by software engineers to conceive and develop programs. Its main principle is to design the tests of the expected properties of the system before the development phase. I argue that this methodology is especially convenient in conceiving applied logics. Indeed, this technique is efficient with most decidable logics having a software (...) implementation. Having a clear list of the desired inferences right from the beginning makes it possible to refine the properties of the system step by step until its completion. I distinguish and detail seven advantages of the usage of TDD for the conception of a logical theory. Most importantly, this methodology increases the predictability of the inferential power of the theory. A second important benefit is that the time required for the conception of the logic goes down dramatically. This methodology will change both ideas and practices. Logic is no longer considered to be a formal science, but rather to be an empirical one. Research in the field is geared toward specific and concrete goals. Programs are considered tools used to verify the conformity of formal theories. To sum up, I defend the view that, in some situations, this way of designing a formal system brings significant benefits, and that the construction of new logics can be conducted similarly to the development of open source software. (shrink)

Theorists have consistently maintained that the most plausible forms of objective consequentialism must be probabilistic if and only if indeterminism is true. This standard position, however popular, lacks sufficient motivation. Assume determinism to be true and an attempt will be made to show that attractive forms of objective consequentialism must be probabilistic - and not for reasons related to our epistemic limitations either. -/- Here it is argued that all extant objective formulations of consequentialism fail to deliver the normative implications (...) that the spirit of objective consequentialism requires. My argument rests upon the claim that certain pairs of subjunctive conditionals with identical antecedents and incompatible consequents are such that neither of the pair is true. -/- Upon leveling the objection, the concept of an "objective" subjunctive probability is introduced and utilized in the transformation of a subjective version of expected act utility consequentialism into an objective version, one that is capable of dealing with the difficulties posed by the objection. I end by indicating some ways in which the closest thing to a plausible, objective form of consequentialism might be developed. (shrink)

There is a heated dispute among consequentialists concerning the following deontic principle.

That all subjunctive conditionals with true antecedents and trueconsequents are themselves also true is implied by every plausibleand popularly endorsed account. But I am wary of endorsing thisimplication. I argue that all presently endorsed accounts fail tocapture the nature of certain subjunctive conditionals in contextsof consequentialist reasoning. I attempt to show that we must allowfor the possibility that some subjunctive conditionals with trueantecedents and true consequents are false, if we are to believethat certain types of straightforward consequentialist reasoningare coherent. I (...) begin by evaluating a pair of morally releventcounterfactuals in a case via David Lewis's account. I then turnto a slight modification of the case, arguing that Lewis'ssemantics fails to generate the correct truth values of thesubjunctive conditionals in the modified case. Finally, I presenta modified version of Lewis's semantics that generates the correctresults in all of the cases. (shrink)

Mind Association 2017Elliott Sober’s first book, Simplicity, defends the view that the simplicity of a theory or hypothesis is a measure of its informativeness – roughly, simpler theories require less new information to be added to them to answer relevant questions of interest. While this measure of simplicity is question-relative, it is still what you might call a global view of simplicity – simplicity means the same thing across different scientific problems and it is always an epistemic virtue. Ockham’s Razor (...) is just good scientific reasoning. Sober’s 1988 book Reconstructing the Past: Parsimony, Evolution, and Inference argues against this global conception of simplicity and replaces it with a local one. Here, in one context parsimony means one thing while in another context it may mean something different. Similarly, whether the more parsimonious hypothesis is to be preferred is also a local matter; it... (shrink)

This paper provides an update semantics for counterfactual conditionals. It does so by giving a dynamic twist to the ‘Premise Semantics’ for counterfactuals developed in Veltman (1976) and Kratzer (1981). It also offers an alternative solution to the problems with naive Premise Semantics discussed by Angelika Kratzer in ‘Lumps of Thought’ (Kratzer, 1989). Such an alternative is called for given the triviality results presented in Kanazawa et al. (2005, this issue).

David Lewis’s counterpart theory is often seen as involving a radical departure from the standard, Kripke-style semantics for modal logic, suggesting that we are dealing with deeply divergent accounts of our modal talk. However, CT captures but one version of the relevant semantic intuition, and does so on the basis of metaphysical assumptions that are ostensibly discretionary. Just as ML can be translated into a language that quantifies explicitly over worlds, CT may be formulated as a semantic theory in which (...) world quantification is purely metalinguistic. And just as Kripke-style semantics is formally compatible with the doctrine of world-boundedness, a counterpart-based semantics may in principle allow for cases of trans-world identity. In fact, one may welcome a framework that is general enough to include both Lewis’s counterpart-based account and Kripke’s identity-based account as distinguished special cases. There are several ways of doing so. The purpose of this paper is to outline a fully general option and to illustrate its philosophical significance, showing how the large variety of intermediate relations that lie between Lewisian counterparthood and Kripkean identity yield a corresponding variety of modal theories that would otherwise remain uncharted. (shrink)

In this paper, Universal any and Negative Polarity Item any are uniformly analyzed as ‘counterfactual’ donkey sentences (in disguise). Their difference in meaning is reduced here to the distinction between strong and weak readings of donkey sentences. It is shown that this explains the universal and existential character of Universal- and NPI-any, respectively, and the positive and negative contexts in which they are licensed. Our uniform analysis extends to the use of any in command and permission sentences. It predicts that (...) whereas the use of any in permission sentences is licensed and gives rise to a universal reading, it is not licensed in command sentences. (shrink)

This paper studies the properties of eight semantic consequence relations defined from a Tarski-logic L and a preference relation ≺. They are equivalent to Shoham’s so-called preferential entailment for smooth model structures, but avoid certain problems of the latter in non-smooth configurations. Each of the logics can be characterized in terms of what we call multi-selection semantics. After discussing this type of semantics, we focus on some concrete proposals from the literature, checking a number of meta-theoretic properties and elaborating on (...) their intuitive motivation. As it turns out, many of their meta-properties only hold in case ≺ is transitive. To tackle this problem, we propose slight modifications of each of the systems, showing the resulting logics to behave better at the intuitive level and in metatheoretic terms, for arbitrary ≺. (shrink)

In ‘belief revision’ a theory is revised with a formula φ resulting in a revised theory . Typically, is in , one has to give up belief in by a process of retraction, and φ is in . We propose to model belief revision in a dynamic epistemic logic. In this setting, we typically have an information state (pointed Kripke model) for the theory wherein the agent believes the negation of the revision formula, i.e., wherein is true. The revision with (...) φ is a program *φ that transforms this information state into a new information state. The transformation is described by a dynamic modal operator [*φ], that is interpreted as a binary relation [ [*φ] ] between information states. The next information state is computed from the current information state and the belief revision formula. If the revision is successful, the agent believes φ in the resulting state, i.e., Bφ is then true. To make this work, as information states we propose ‘doxastic epistemic models’ that represent both knowledge and degrees of belief. These are multi-modal and multi-agent Kripke models. They are constructed from preference relations for agents, and they satisfy various characterizable multi-agent frame properties. Iterated, revocable, and higher-order belief revision are all quite natural in this setting. We present, for an example, five different ways of such dynamic belief revision. One can also see that as a non-deterministic epistemic action with two alternatives, where one is preferred over the other, and there is a natural generalization to general epistemic actions with preferences. (shrink)