Chapter 2 epistemic logic and information as range epistemic logic was developed originally for the analysis of the philosophical notion of knowledge hintikka 1962, and as such, it has generated controversy. As their views diverged greatly, we propose a categorisation of the eld of epistemic logic into four research agendas. Epistemic logic stanford encyclopedia of philosophy. The semantics of epistemic logic are typically given in terms of possible. In modern philosophy, however, epistemic logic is used as a technical term not only for the logic of knowledge but also for the. Semantically, a formula is successful if and only if for any pointed. Semantically, a formula is successful if and only if for any pointed model where it is true, it remains true after deleting all points where the formula was false. Dynamic epistemic logic is the study of modal logics of model change.
Epistemic logic is the shining star of reschers provocative trilogy on realism, knowledge, and our cognitive imitations. The application of logical techniques to the study of knowledge or knowledge claims is called epistemic logic. Epistemic closure and epistemic logic i 3 failures are ubiquitous given nozicks theory of knowledge. In a wider sense, it gives a formal account of the informational attitude that agents may have, and covers notions like knowledge, belief, uncertainty, and. An interpretation of default logic in minimal temporal. The modal knowledge operators in epistemic logic are formally interpreted by.
Moorean phenomena in epistemic logic uc berkeley philosophy. Typically, del focuses on situations involving multiple agents and studies how their knowledge changes when events occur. The main result of part i is an exact characterization in propositional epistemic logic of the closure properties of knowledge according to the ra, tracking, and safety theories, as formalized. Epistemic modal logic is a subfield of modal logic that is concerned with reasoning about knowledge.
An extended interpreted system model for epistemic logics kaile su1. Thus, taken literally, epistemic logic represents the logic of knowledge. Structures for epistemic logic 3 tion on the sets of states. Moorean phenomena in epistemic logic, lori workshop, esslli 2010 1. Epistemic logic has become a major field of philosophical logic ever since the groundbreaking work by hintikka 58. In modern philosophy, however, epistemic logic is used as a technical term not only for the logic of knowledge but also for the logic of belief. As a combination of dynamic logic and epistemic logic, dynamic epistemic logic is a young field of research. Published version in journal of philosophical logic,vol. Finite identification from the viewpoint of epistemic update. We establish a logic of knowledge and certainty, called kc logic, with a sound and complete proof system. Epistemic closure has been a central issue in epistemology over the last forty years. Disagreement, questionbegging and epistemic selfcristicism. Modal logic epistemic logic artificial intelligence. The main results of this paper are summarized as follows.
For example, the statement john is happy might be qualified by saying that john is usually happy, in which case the term usually is functioning as. In some cases, for example, emergent social phenomena depend on agents. In this book, we use it in a completely neutral manner, as a formalization of the notion information as range in the introduction. It also contains an overview of the handbook, and a brief history of epistemic logic and pointers to the literature. While epistemology has a long philosophical tradition dating back to ancient greece, epistemic logic is a much more recent development with applications in many fields, including philosophy, theoretical computer science, artificial intelligence, economics and linguistics. The term epistemic logic is often applied also to logics of related notions, such as logics of belief more strictly, doxastic logics and justification. It really started in 1989 with plazas logic of public announcement. Holliday university of california, berkeley abstract this chapter provides a brief introduction to propositional epistemic logic and its applications to epistemology.
It shows how epistemic logic supplements temporal and other formal systems designed to specify and verify concurrent programs. Individuals are believed to hold both naive and sophisticated resources in their cognitive structures. Introduction this handbook chapter explores some themes which relate general topology and epistemic logic. Beyond philosophy proper, epistemic logic flourishes in theoretical computer. In particular, we discuss here neighbourhood semantics and topological semantics. Keywords nonmonotonic reasoning, default logic, temporal logic. Del pronounced dell is a highly active area of applied logic that touches on topics in many areas, including formal and social epistemology, epistemic and doxastic logic, belief revision, multiagent and distributed systems, artificial intelligence, defeasible and nonmonotonic reasoning, and epistemic game theory. Viwith w any set of points, r w wany relation, and v. In fact, it is selfrefuting in that it always becomes false when it is learned. Then we augment the language of propositional logic by knowledge operators one for each agent, and form formulae in the obvious way. Agreement theorems from the perspective of dynamic. Different epistemic resources are activated by different contexts.
Agreement theorems from the perspective of dynamicepistemic. A modala word that expresses a modalityqualifies a statement. Categories doxastic and epistemic logic in logic and philosophy of logic. Modal logic epistemic logic eric pacuit university of maryland, college park ai. Contradictions are, instead, epistemically understood as con. Hammer and elby treat epistemic beliefs as made up of a range of epistemic resources. Moorean phenomena in epistemic logic, lori workshop, esslli 2010 2. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. It also turns out that a logic of questions and answers, sometimes called. Despite its various successful applications in theoretical computer science, ai, and game theory, the technical development of the field has been mainly focusing on the propositional part, i. Many epistemic logics are modal logics, whose language contains one or more knowledge operators and whose semantics is given in terms of.
The field encompasses epistemological concepts such as knowledge, belief, memory, information, and perception. Second, one seeks to describe particular, concrete phenomena. Semantically, a formula is successful if and only if for any pointed model where it is true, it remains true after deleting all points. Dynamic logic for belief revision institute for logic. Dynamic epistemic logic an encyclopedia of philosophy.
Epistemic theory when the identity of agents is only partially speci. Abstract the possibility of justified true belief without knowledge is normally motivated by informally classified examples. Dynamic epistemic logic del is a logical framework dealing with knowledge and information change. Therefore, our work establishes a unifying framework for both nested logic programs and epistemic logic programs.
Kooi 2003 journal of logic, language and information 12 4. For simplicitys sake it is usually assumed that the agents are homogeneous, i. So an epistemic logic for agents consists of copies of a. In the area of applications of topological ideas in epistemic logic, we include a section on the following topics. Chalmers philosophy program research school of social sciences australian national university confronted with the apparent explanatory gap between physical processes and consciousness, philosophers have reacted in many different ways. Modal logic is a type of formal logic primarily developed in the 1960s that extends classical propositional and predicate logic to include operators expressing modality. Moorean phenomena in epistemic logic, lori workshop, esslli 2010 3. These events can change factual properties of the actual world they are called ontic events. A comparison between the various semantics for default logic will show the differences and similarities of these approaches and ours.
It becomes s5 if we assume an agent always has correct observations. For example, all manner of linguistic phenomena involving time have led to proposals for using the models from temporal logic. Epistemic logic is a promising tool for analyzing distributed systems. Mai, interested in this theory, took the peircean constructs, and applied them to the indexing process mai 2000, 2001. Epistemology, theory, and methodology in knowledge. Leitgeb has pointed out that the aim of dynamic epistemic logic and the like is to. New york university new york, new york leora morgenstern ibm watson research center hawthorn, new york august 28, 1983 1 introduction it is to the advantage of a thinking creature to be aware of knowledge and thought and to be able to reason about them. These agendas will function as a starting point for a discussion of the advantages and disadvantages of idealisations in epistemic logic. Phenomenological description aims to make explicit essential features implicit in the livedworld the world as we act in it prior to any theorizing about it.
The phenomena of unsuccessfulness of announcements was noted. Ourapproach shows a strong parallel to epistemic logic. We owe to plaza a description of the initial model for solving the sumandproduct puzzle and the formalization of the announcements in epistemic logic, to be presented in section 4. Phenomenal concepts and the explanatory gap david j. We show that in logics of knowledge and belief for a single agent extended by s5, moorean phenomena are the source of all selfrefutation. For example, the statement john is happy might be qualified by saying that john is usually happy, in which. In terms of models, this means that the current static model already contains all information about what might happen when agents communicate what. No previous exposure to epistemic logic is assumed. Dynamic logic for belief revision 5 to an equivalent formula inside the static pure epistemic language. Dynamic epistemic logic stanford encyclopedia of philosophy. A wellknown open problem in epistemic logic is to give a syntactic characterization of the successful formulas.
In this approach, the state of a distributed system is characterized using epistemic concepts, such as, the information available to. As in propositional epistemic logic, in an epistemic logic of concepts the main issue is. The propositions are, in this case, the coordination of the phenomena and the constructs, that once assembled in a particular order, tell the story of different types of signs, according to peirce. According to versions of the relevant alternatives and subjunctivist theories of knowledge, epistemic closure can fail. Moorean phenomena in epistemic logic lori workshop, esslli 2010 wes holliday and thomas icard logical dynamics lab, csli department of philosophy, stanford university august 16, 2010 wes holliday and thomas icard. Modeling of phenomena and dynamic logic of phenomena arxiv. An extended interpreted system model for epistemic logics. Naming and identity in a multiagent epistemic logic second intl. Wolfgang lenzen, recent work in epistemic logic philpapers. Furthermore, we also provide a characterization of the strong equivalence of two nested epistemic logic programs. Obviously, by itself, tweak ing the formal apparatus of epistemic logic does not solve traditional epistemological problems. Icard, iii department of philosophy stanford university stanford, california, usa abstract a wellknown open problem in epistemic logic is to give a syntactic characterization of the successful formulas. Dynamic epistemic logic internet encyclopedia of philosophy.
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