There have been attempts to get some logic out of beliefdynamics, i.e. attempts to deﬁne the constants of propositional logic in terms of functions from sets of beliefs to sets of beliefs. It is interesting to see whether something similar can be done for ontological categories, i.e. ontological constants. The theory presented here will be a (modest) expansion of beliefdynamics: it will not only incorporate beliefs, but also parts of beliefs, so called belief (...) fragments. On the basis of this we will give a belief-dynamical account of the ontological categories of states of aﬀairs, individuals, properties of arbitrary adicities and properties of arbitrary orders. (shrink)
In the companion paper (Towards a “sophisticated” model of beliefdynamics. Part I), a general framework for realistic modelling of instantaneous states of belief and of the operations involving them was presented and motivated. In this paper, the framework is applied to the case of belief revision. A model of belief revision shall be obtained which, firstly, recovers the Gärdenfors postulates in a well-specified, natural yet simple class of particular circumstances; secondly, can accommodate iterated revisions, (...) recovering several proposed revision operators for iterated revision as special cases; and finally, offers an analysis of Rott’s recent counterexample to several Gärdenfors postulates , elucidating in what sense it fails to be one of the special cases to which these postulates apply. (shrink)
It is well-known that classical models of belief are not realistic representations of human doxastic capacity; equally, models of actions involving beliefs, such as decisions based on beliefs, or changes of beliefs, suffer from a similar inaccuracies. In this paper, a general framework is presented which permits a more realistic modelling both of instantaneous states of belief, and of the operations involving them. This framework is motivated by some of the inadequacies of existing models, which it overcomes, whilst (...) retaining technical rigour in so far as it relies on known, natural logical and mathematical notions. The companion paper (Towards a “sophisticated” model of beliefdynamics. Part II) contains an application of this framework to the particular case of belief revision. (shrink)
In this paper we explore the relationship between norms of belief revision that may be adopted by members of a community and the resulting dynamic properties of the distribution of beliefs across that community. We show that at a qualitative level many aspects of social belief change can be obtained from a very simple model, which we call ‘threshold influence’. In particular, we focus on the question of what makes the beliefs of a community stable under various dynamical (...) situations. We also consider refinements and alternatives to the ‘threshold’ model, the most significant of which is to consider changes to plausibility judgements rather than mere beliefs. We show first that some such change is mandated by difficult problems with belief-based dynamics related to the need to decide on an order in which different beliefs are considered. Secondly, we show that the resulting plausibility-based account results in a deterministic dynamical system that is non-deterministic at the level of beliefs. (shrink)
In researching presuppositions dealing with logic and dynamic of belief we distinguish two related parts. The first part refers to presuppositions and logic, which is not necessarily involved with intentional operators. We are primarily concerned with classical, free and presuppositonal logic. Here, we practice a well known Strawson’s approach to the problem of presupposition in relation to classical logic. Further on in this work, free logic is used, especially Van Fraassen’s research of the role of presupposition in supervaluations logical (...) systems. At the end of the first part, presuppositional logic, advocated by S.K. Thomason, is taken into consideration. The second part refers to the presuppositions in relation to the logic of the dynamics of belief. Here the logic of belief change is taken into consideration and other epistemic notions with immanent mechanism for the presentation of the dynamics. Three representative and dominant approaches are evaluated. First, we deal with new, less classical, situation semantics. Besides Strawson’s theory, the second theory is the theory of the belief change, developed by Alchourron, Gärdenfors, and Makinson (AGM theory). At the end, the oldest, universal, and dominant approach is used, recognized as Hintikka’s approach to the analysis of epistemic notions. (shrink)
We investigate how belief change in cooperative dialogues can be handled within a modal logic of action, belief, and intention. We first review the main approaches of the literature, and point out some of their shortcomings. We then propose a new framework for belief change. Our basic notion is that of a contextual topic: we suppose that we can associate a set of topics with every agent, speech act, and formula. This allows us to talk about an (...) agent's competence, belief adoption, and belief preservation. Based on these principles we analyse the agents' belief states after a speech act. We illustrate our theory by a running example. (shrink)
This paper studies the idea of conservatism with respect to belief change strategies in the setting of unary, iterated belief revision functions (based on the conclusions of Rott, ‘Coherence and Conservatism in the Dynamics of Belief, Part I: Finding the Right Framework’, Erkenntnis 50, 1999, 387–412). Special attention is paid to the case of ‘basic belief change’ where neither the (weak) AGM postulates concerning conservatism with respect to beliefs nor the (stong) supplementary AGM postulates concerning (...) dispositional coherence need to be satisfied. One‐step belief change generated by ‘basic entrenchment’ is combined with a natural conservative method of revising entrenchment relations. A logical characterization of this method is presented, and it is compared with three other methods known from the literature which I call ‘external’, ‘radical’ and ‘moderate’ belief revision. While conservative belief change turns out to be incoherent in its treatment of the recency of information, moderate belief change is more satisfactory in this respect. (shrink)
What I’m calling “Subjective Logic” is a new approach to logic. Fundamentally it is a theory about what sentences mean, i.e. a theory of the proposition, but it includes an account of logical consequence, the propositional connectives, probability, and the nature of truth.
Indexical beliefs pose a special problem for standard theories of Bayesian updating. Sometimes we are uncertain about our location in time and space. How are we to update our beliefs in situations like these? In a stepwise fashion, I develop a constraint on the dynamics of indexical belief. As an application, the suggested constraint is brought to bear on the Sleeping Beauty problem.
In this paper I discuss the foundations of a formal theory of coherent and conservative belief change that is suitable to be used as a method for constructing iterated changes of belief, sensitive to the history of earlier belief changes, and independent of any form of dispositional coherence. I review various ways to conceive the relationship between the beliefs actually held by an agent and her belief change strategies, show the problems they suffer from, and suggest (...) that belief states should be represented by unary revision functions that take sequences of inputs. Three concepts of coherence implicit in current theories of belief change are distinguished: synchronic, diachronic and dispositional coherence. Diachronic coherence is essentially identified with what is known as conservatism in epistemology. The present paper elaborates on the philosophical motivation of the general framework; formal details and results are provided in a companion paper. (shrink)
This paper presents eight (previously unpublished) adaptive logics for belief revision, each of which define a belief revision operation in the sense of the AGM framework. All these revision operations are shown to satisfy the six basic AGM postulates for belief revision, and Parikh's axiom of Relevance. Using one of these logics as an example, we show how their proof theory gives a more dynamic flavor to belief revision than existing approaches. It is argued that this (...) turns belief revision (that obeys Relevance) into a more natural undertaking, where analytic steps are performed only as soon as they turn out to be necessary in order to uphold certain beliefs. (shrink)
The characteristic difference between laws and accidental generalizations lies in our epistemic or inductive attitude towards them. This idea has taken various forms and dominated the discussion about lawlikeness in the last decades. Likewise, the issue about ceteris paribus conditions is essentially about how we epistemically deal with exceptions. Hence, ranking theory with its resources of defeasible reasoning seems ideally suited to explicate these points in a formal way. This is what the paper attempts to do. Thus it will turn (...) out that a law is simply the deterministic analogue of a sequence of independent, identically distributed random variables. This entails that de Finetti's representation theorems can be directly transformed into an account of confirmation of laws thus conceived. (shrink)
Using probability functions defined over a simple language as models of states of belief, my goal in this article has been to analyse contractions and revisions of beliefs. My first strategy was to formulate postulates for these processes. Close parallels between the postulates for contractions and the postulates for revisions have been established - the results in Section 5 show that contractions and revisions are interchangeable. As a second strategy, some suggestions for more or less explicit constructive definitions of (...) the revision process (and indirectly also of the contraction process) were then presented. However, the results in Section 6 are less conclusive than in the earlier ones. This problem area still awaits further development. (shrink)
Argumentation is a dialogical attempt to bring about a desired change in the beliefs of another agent – that is, to trigger a specific belief revision process in the mind of such agent. However, so far formal models of belief revision widely neglected any systematic comparison with argumentation theories, to the point that even the simplest argumentation structures cannot be captured within such models. In this essay, we endeavour to bring together argumentation and belief revision in the (...) same formal framework, and to highlight the important role played by Toulmin’s layout of argument in fostering such integration. (shrink)
This paper examines three accounts of the sleeping beauty case: an account proposed by Adam Elga, an account proposed by David Lewis, and a third account defended in this paper. It provides two reasons for preferring the third account. First, this account does a good job of capturing the temporal continuity of our beliefs, while the accounts favored by Elga and Lewis do not. Second, Elga’s and Lewis’ treatments of the sleeping beauty case lead to highly counterintuitive consequences. The proposed (...) account also leads to counterintuitive consequences, but they’re not as bad as those of Elga’s account, and no worse than those of Lewis’ account. (shrink)
Having entered into the problem structuring methods, system dynamics (SD) is an approach, among systems’ methodologies, which claims to recognize the main structures of socio-economic behaviors. However, the concern for building or discovering strong philosophical underpinnings of SD, undoubtedly playing an important role in the modeling process, is a long-standing issue, in a way that there is a considerable debate about the assumptions or the philosophical foundations of it. In this paper, with a new perspective, we have explored theory (...) of knowledge in SD models and found strange similarities between classic epistemological concepts such as justification and truth, and the mechanism of obtaining knowledge in SD models. In this regard, we have discussed related theories of epistemology and based on this analysis, have suggested some implications for moderating common problems in the modeling process of SD. Furthermore, this research could be considered a reword of system dynamics modeling principles in terms of theory of knowledge. (shrink)