Ahti-Veikko J. Pietarinen

Professor, PhD, Chair in Philosophy

Department of Philosophy, History, Culture and Art Studies, University of Helsinki

Department of Public Administration, Tallinn University of Technology

Scientific presentations

s

* = invited (99)

2012:

2011:

2010:

2009:

2008:

2007:

2006:

2005:

2004:

This talk traces the joint roots of logical and game-theoretic developments, starting from the late medieval obligationes, through the central ideas of  pragmatism, and ending at the mid-50s Princeton campus, the formal nexus of these mutual developments. The excursus shows that logic and games, mutually conceived, are an old but diversiform intellectual idea, the characteristics of which we are only gradually beginning to appreciate.
To express knowledge and communication in multi-agents systems, a hybrid of possible-worlds and game-theoretic semantics is defined for the language of Independence-Friendly (IF) first-order epistemic logic. The language distinguishes between specific and non-specific knowledge by hiding worlds. Identification on uniform domains is via imperfect information that agrees with cross-world references by coordinating information sets with world-bound aspects of individuals. Applications range from intentional identities (cross-modal anaphora) to reasoning and communication about focussed knowledge.
Peirce was a visual interpreter of language, which led him to adopt the idea of the diagrammatisation of logic and so to the theory of existential graphs, which he claimed “put before us moving pictures of thought” (c.1905). This paper uncovers several senses of “movement” of these “pictures of thought”. I will show how they may be rendered as actual moves in the correlated extensive games in the game-theoretic sense. These games lend themselves to a diagrammatic and semeiotic approach to the meaning of propositions or complex concepts in a natural way. Accordingly, I will identify and investigate some of the relations between the resulting dialogical or game-theoretic interpretation and Peirce’s theory of communicative or dialogical semiosis. I will also consider his method of endoporeutic in interpreting the graphs, and the presupposed knowledge and the common ground of agents involved in the process of diagrammatic interpretation.
2003:
The meaning of utterances may be understood as Wittgenstein’s language games of “showing or telling what one sees”, which Wittgenstein held to be “one of the most fundamental language games”. I argue that they provide motivation for the use of games in relation to logic and semantics that some commentators have called for. One general implication is that the notions of saying and showing converge in his late philosophy.
  • 39.   "Historical and Peircean notions of pragmatics", The 16th International Conference on Historical Linguistics, Copenhagen, August 2003.
  • 38.  "Agenda cognitive linguistics: C. S. Peirce and the scope of common ground in theories of communication", The 8th International Conference of Cognitive Linguistics, Logroño, July 2003.
To use language in communication is to build shared models of chains of utterances. This happens in mental models, discourse structures and theories of relevance alike. The semiotic theory of Charles S. Peirce adds richer logic. It has (i) a three-way notion of reference; (ii) a copula, relating terms to the elements of the universe of discourse, presupposing that the universe is well known and mutually known to be known and agreed to exist between speaker and hearer; (iii) the line of identity, representing besides identity particularity, existence, selection, predication, and coreference, unifying the semantics of the verb for "being"; (iv) the interpretants, divided into intentional and effectual halves, giving rise to communicational interpretants, the determinations of mind into which models of the attitudes of the speaker and the interpreter are welded. Consequently, Peirce antedates the notions of common ground, knowledge and salience, but the common ground it not merely about prescriptions of legitimate moves in dialogue games but involves habitual considerations. Communicational interpretants emerge by reference to common experience and the summum bonum of communicative goals (apud triangulation).
  • 37.  "Reversed interactive epistemology", The XXI World Congress of Philosophy, Istanbul, August 2003.
New logical perspectives to epistemology come to view by a suitable combination of the theory of semantic games and epistemic logic. In particular, by relaxing the assumption of perfect information we admit that even if ideally rational, the knowing agents may not be able to establish the truths of all the constructions of their knowledge. Although being thus forced to make concessions to the Skeptic, the Inquirer's process of trying to find out the truth of agent's knowledge statements remains the defining characteristic of semantic games: analogously to other semantic games, in epistemic logic they serve as enriched mediators between different kinds of knowledge and the world by also searching possible worlds.
This paper presents a topological and game-theoretic extension of the system of Existential Graphs (EG). EGs were Charles S. Peirce's diagrammatic and iconic approach to logic. By scribing the graphs on assertion spaces of higher dimensions, this extension provides the precise iconic counterpart to the Independence-Friendly (IF) restatement of first-order logic. Apart from improved ways of performing conceptual modelling of natural language assertions, this extension reveals contrasting facets of the diagrammatic concept of negation, and shows the true proportions of Peirce's sign- and model-theoretic thinking in plunging into the notions of identity, continuity and quantification.
  • 35.  "Dialogue foundations and informal logic", The 25th International Symposium on Informal Logic (IL@25), Windsor, May 2003.
  • 34*.   "Moving pictures of thought", Perspectives on the Philosophy of Charles S. Peirce, University of Helsinki, February 2003.

2002:

  • 33.  "Peirce's concept of communication and its contemporary relevance", A New Research Agenda for Philosophy, Budapest, Hungarian Academy of Sciences, November 2002.
  • 32.  "Independence-friendly logic and incomplete information", Philosophical Insights into Logic and Mathematics: The History and Outcome of Alternative Semantics and Syntax (PILM’02), Nancy, October 2002.
  • 31.  "Diagrammatic logic and game-playing",  International Workshop on Visual Representations and Interpretations (VRI'02), Liverpool, September 2002.
  • 30.  "Awareness in logic and neuroscience", The 1st IEEE International Conference on Cognitive Informatics (ICCI’2002), Calgary, August 2002.
  • 29.  "Some social metaphors in logic", The 2nd International Workshop on Computational Models of Scientific Reasoning and Applications (II CMSRA), Las Vegas, July 2002.
  • 28.    "Logic, language-games and ludics: Some Wittgensteinian themes in the foundations of logic and computation", Logic Colloquium 2002, August 2002; Annual Meeting of the European Society for Philosophy and Psychology, Lyon, July 2002.
  • 27.    "Negotiation games and conflict resolution in logical semantics", The AAAI-02 Workshop on Meaning Negotiation (MeaN-02), Edmonton, July 2002.
  • 26.    "Inner and outer knowledge: The case for epistemic logic", The 4th European Congress of Analytical Philosophy (ECAP IV), Lund, June 2002.
  • 25.    " Knowledge constructions for artificial intelligence", The 13th International Symposium on Methodologies for Intelligent Systems (ISMIS 2002), Lyon, June 2002.
  • 24.    "Modelling logical concepts by diagrammatic systems", The 11th European-Japanese Conference on Information Modelling and Knowledge Bases (EJC 2002), Krippen, May 2002.
  • 23.    "Possible-worlds ontology for the semantic web", The 11th International World Wide Web Conference (WWW2002), Honolulu, May 2002.
  • 22.    "Aspekti ja strateginen merkitys" (in Finnish; "Aspect and strategic meaning"), Kielitieteen päivät 2002, University of Helsinki, May 2002.
  • 21*.  "Filosofinen logiikka ja informatiikan vallankumous" (in Finnish; "Philosophical logic and the revolution in informatics"), Finnish Philosophical Society, Helsinki, April 2002.
  • 20.  "Games and logics of knowledge for multi-agent systems", Mexican International Conference on Artificial Intelligence (MICAI 2002), April 2002.
  • 19.  "A negation-less theory of negative polarity items", The 38th Chicago Linguistic Society Meeting, Chicago Linguistic Society, April 2002.
  • 18.  "Evolution in semantic language-games", The 4th International Conference on Evolution of Language (Evolang'2002), Harvard University, March 2002.
  • 17*.    "Peirce's game-theoretical ideas in logic", University of Helsinki, The Metaphysical Club, February 2002.
  • 16*.  "The semantic web and epistemic logic" (invited paper), The 2 nd International Conference on Advances in Infrastructure for Electronic Business, Science and Education on the Internet (SSGRR-2002), L'Aquila, January 2002.
  • 15.  "Semanttiset pelit logiikassa ja kielessä" (in Finnish; "Semantic games in logic and language"), University of Helsinki, January 2002.

2001:

  • 14.    "A logic of parallel processing and parallel processing of logic", The 1st International WSES Conference on Automation and Information (AITA 2001), Skiathon, September 2001.
  • 13.  "Reasoning about focussed knowledge in multi-agent systems", The 3rd International Conference on Cognitive Science (ICCS'2001), Beijing, August 2001.
  • 12.  "The role of epistemic logic in cognitive science", The 3rd International Conference on Cognitive Science (ICCS'2001) , Beijing, August 2001.
  • 11*.  "Game theory and multi-agent systems" (invited paper), The 1st International Conference on Advances in Infrastructure for Electronic Business, Science and Education on the Internet (SSGRR-2001), L'Aquila, August 2001.
  • 10*.  "Varieties of IFing", ESSLLI'01 Workshop on Logic and Games, Helsinki, August 2001.
  • 9.    "C.S. Peirce's game semantics", Logic Colloquium'01, Vienna, August 2001.

2000:

  • 8.     "Semantic games for generalised quantifiers", Sinn und Bedeutung V, Amsterdam, December 2000.
  • 7.    "A logical approach to knowledge in imperfect information multi-agent systems", The 10th International Conference on Computation and Information (ICCI’00), Kuwait City, November 2000.
  • 6.    "Game theory and the semantics of modal notions: Some philosophical and historical encounters", The 1st International Workshop on the History and Philosophy of Logic, Mathematics and Computation, San Sebastian, November 2000.
  • 5.    "Some remarks on games logic plays", Logic Colloquium'00, Paris, July 2000.

1999:

  • 4.    "Informational independence in epistemic logic", The 11th International Congress in Logic, Methodology and Philosophy of Science (LMPS 1999) , Cracow, August 1999.
  • 3.    "Independence-friendly epistemic logic and some non-firstorderisable concepts", The 9th European-Japanese Conference on Information Modelling and Knowledge Bases, Iwate Prefectural University, May 1999.

1998:

  • 2.    "Imperfect information in epistemic logic", The Third ESSLLI Student Session, The 10th European Summer School of Logic, Language and Information, Saarbrücken, August 1998.
We argue that so-called mutual de dicto/de re knowledge between agents is not expressible in classical first-order epistemic logic. It can, however, be captured in the epistemic logic of imperfect information, extended to the case of multiple agents. However, giving semantics for formulae involving imperfect information by semantic games poses difficulties. First, the modelling of mutual knowledge gives rise to cyclic dependencies, and it is therefore not clear how the games can be played on such prefixes. Second, the semantic side of imperfect information needs to be settled. We point out the need for a new inscoping device in addition to outscoping, and tackle the question of what the existence of winning strategies in epistemic logic of imperfect information means.

 

 

Department of Philosophy | University of Helsinki