Categories doxastic and epistemic logic in logic and philosophy of logic. Moorean phenomena in epistemic logic, lori workshop, esslli 2010 3. Dynamic epistemic logic an encyclopedia of philosophy. It shows how epistemic logic supplements temporal and other formal systems designed to specify and verify concurrent programs. An extended interpreted system model for epistemic logics kaile su1. Moorean phenomena in epistemic logic, lori workshop, esslli 2010 1. Dynamic logic for belief revision institute for logic. Keywords nonmonotonic reasoning, default logic, temporal logic. Epistemic closure and epistemic logic i 3 failures are ubiquitous given nozicks theory of knowledge. Epistemology, theory, and methodology in knowledge. 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. Finite identification from the viewpoint of epistemic update. 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. In this approach, the state of a distributed system is characterized using epistemic concepts, such as, the information available to.
Holliday university of california, berkeley abstract this chapter provides a brief introduction to propositional epistemic logic and its applications to epistemology. In some cases, for example, emergent social phenomena depend on agents. 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. Epistemic theory when the identity of agents is only partially speci. Moorean phenomena in epistemic logic uc berkeley philosophy. Beyond philosophy proper, epistemic logic flourishes in theoretical computer. Mai, interested in this theory, took the peircean constructs, and applied them to the indexing process mai 2000, 2001. 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.
As a combination of dynamic logic and epistemic logic, dynamic epistemic logic is a young field of research. These agendas will function as a starting point for a discussion of the advantages and disadvantages of idealisations in epistemic logic. Epistemic logic has become a major field of philosophical logic ever since the groundbreaking work by hintikka 58. Kooi 2003 journal of logic, language and information 12 4. 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. Modal logic epistemic logic eric pacuit university of maryland, college park ai. Phenomenal concepts and the explanatory gap david j. 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. Dynamic epistemic logic is the study of modal logics of model change. In modern philosophy, however, epistemic logic is used as a technical term not only for the logic of knowledge but also for the.
It really started in 1989 with plazas logic of public announcement. Individuals are believed to hold both naive and sophisticated resources in their cognitive structures. An interpretation of default logic in minimal temporal. The phenomena of unsuccessfulness of announcements was noted. 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. Therefore, our work establishes a unifying framework for both nested logic programs and epistemic logic programs. There, the objective side can be represented by an algebra of true propositions, and an epistemic subject can represent some of these propositions as what she believes to be true. Semantically, a formula is successful if and only if for any pointed. Published version in journal of philosophical logic,vol.
We establish a logic of knowledge and certainty, called kc logic, with a sound and complete proof system. 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. In particular, we discuss here neighbourhood semantics and topological semantics. Epistemic logics are logics that allow one to reason about knowledge in some way. Agreement theorems from the perspective of dynamicepistemic. According to versions of the relevant alternatives and subjunctivist theories of knowledge, epistemic closure can fail. Dynamic logic for belief revision 5 to an equivalent formula inside the static pure epistemic language. The modal knowledge operators in epistemic logic are formally interpreted by. Viwith w any set of points, r w wany relation, and v. 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. Different epistemic resources are activated by different contexts. Semantically, a formula is successful if and only if for any pointed model where it is true, it remains true after deleting all points. In this book, we use it in a completely neutral manner, as a formalization of the notion information as range in the introduction. A wellknown open problem in epistemic logic is to give a syntactic characterization of the successful formulas.
A comparison between the various semantics for default logic will show the differences and similarities of these approaches and ours. No previous exposure to epistemic logic is assumed. A modal epistemic logic for agents is obtained by joining together modal logics, one for each agent. Many epistemic logics are modal logics, whose language contains one or more knowledge operators and whose semantics is given in terms of. It becomes s5 if we assume an agent always has correct observations. Wolfgang lenzen, recent work in epistemic logic philpapers. Introduction this handbook chapter explores some themes which relate general topology and epistemic logic. Leitgeb has pointed out that the aim of dynamic epistemic logic and the like is to. Dynamic epistemic logic del is a logical framework dealing with knowledge and information change. Contradictions are, instead, epistemically understood as con.
These events can change factual properties of the actual world they are called ontic events. In terms of models, this means that the current static model already contains all information about what might happen when agents communicate what. Two nested epistemic logic programs are strong equivalent if and only if they are equivalent in the epistemic htlogic. Epistemic closure has been a central issue in epistemology over the last forty years. Epistemic logic is the shining star of reschers provocative trilogy on realism, knowledge, and our cognitive imitations. It also turns out that a logic of questions and answers, sometimes called. Epistemic logic stanford encyclopedia of philosophy.
Epistemic logic is a promising tool for analyzing distributed systems. Second, one seeks to describe particular, concrete phenomena. We show that in logics of knowledge and belief for a single agent extended by s5, moorean phenomena are the source of all selfrefutation. Obviously, by itself, tweak ing the formal apparatus of epistemic logic does not solve traditional epistemological problems. Agreement theorems from the perspective of dynamic. 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. 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. The term epistemic logic is often applied also to logics of related notions, such as logics of belief more strictly, doxastic logics and justification. So an epistemic logic for agents consists of copies of a. Dynamic epistemic logic internet encyclopedia of philosophy. 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.
Typically, del focuses on situations involving multiple agents and studies how their knowledge changes when events occur. Abstract the possibility of justified true belief without knowledge is normally motivated by informally classified examples. The final two chapters argue 1 that we can only explain why rationality matters from the epistemic point of view if we reject the nearly universal assumption that all derivative epistemic value is instrumental value, and 2 that there are powerful reasons to reject this assumption, since it is the true origin of the socalled swamping problem. The semantics of epistemic logic are typically given in terms of possible. 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. Structures for epistemic logic 3 tion on the sets of states. 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. Modeling of phenomena and dynamic logic of phenomena arxiv. As their views diverged greatly, we propose a categorisation of the eld of epistemic logic into four research agendas. As in propositional epistemic logic, in an epistemic logic of concepts the main issue is. Disagreement, questionbegging and epistemic selfcristicism. 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. Then we augment the language of propositional logic by knowledge operators one for each agent, and form formulae in the obvious way. It also contains an overview of the handbook, and a brief history of epistemic logic and pointers to the literature.
Modal logic epistemic logic artificial intelligence. For simplicitys sake it is usually assumed that the agents are homogeneous, i. Furthermore, we also provide a characterization of the strong equivalence of two nested epistemic logic programs. Epistemic modal logic is a subfield of modal logic that is concerned with reasoning about knowledge. The field encompasses epistemological concepts such as knowledge, belief, memory, information, and perception. Moorean phenomena in epistemic logic, lori workshop, esslli 2010 2. The application of logical techniques to the study of knowledge or knowledge claims is called epistemic logic. Hammer and elby treat epistemic beliefs as made up of a range of epistemic resources. 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. Naming and identity in a multiagent epistemic logic second intl. Ourapproach shows a strong parallel to epistemic logic.
A modala word that expresses a modalityqualifies a statement. 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. An extended interpreted system model for epistemic logics. In the area of applications of topological ideas in epistemic logic, we include a section on the following topics. In fact, it is selfrefuting in that it always becomes false when it is learned. Thus, taken literally, epistemic logic represents the logic of knowledge. 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. 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. For example, all manner of linguistic phenomena involving time have led to proposals for using the models from temporal logic.
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