Awareness and partitional information structures
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
This is the first of two papers where we present a formal model of unawareness. We contrast unawareness with certainty and uncertainty. A subject is certain of something when he knows that thing; he is uncertain when he does not know it, but he knows he does not: he is consciously uncertain. On the other hand, he isunaware of something when he does not know it, and he does not know he does not know, and so on ad infinitum: he does not perceive, does not have in mind, the object of knowledge. The opposite of unawareness is awareness, which includes certainty and uncertainty.
This paper has three main purposes. First, we formalize the concept of awareness, and introduce a symmetry axiom which states that a subject can be aware of something, ϕ say, if and only if he is aware of its negation not-ϕ; in other words, that ϕ and not-ϕ are perceived together, or neither is. We then derive the basic properties of awareness.
The second purpose is to prove a different axiomatic characterization, based on the concept of awareness of the system which underlies the model of information with partitional structures (known asS5).
The third purpose of this paper is to show that without a substantial weakening of the rules of inferences normally assumed in modal logic a satisfactory model of unawareness, which includes the symmetry axiom, is impossible. This alternative approach is developed in a second paper by the same authors.
- Aumann, R. A. (1976) Agreeing to Disagree. The Annals of Statistics 4: pp. 1236-1239
- Brown, D. and Geanakoplos, J.: 1988, Common Knowledge without Partitions, unpublished manuscript.
- Chellas, B.: 1980,Modal Logic: an Introduction, Cambridge University Press.
- Fagin, R., Halpern, J. (1988) Belief, Awareness, and Limited Reasoning. Artificial Intelligence 34: pp. 39-76
- Geanakoplos, J.: 1989, Game Theory without Partitions, and Applications to Speculation and Consensus; Cowles Foundation Discussion Paper no. 914.
- Kleene, Stephen C.: 1967,Introduction to Metamathematics, North Holland.
- Lismont, L., Mongin, P. (1994) On the Logic of Common Belief and Common Knowledge. Theory and Decision 37: pp. 75-106
- Milgrom, P., Stokey, N. (1982) Information, Trade and Common Knowledge. Journal of Economic Theory 26: pp. 17-27
- Modica, S. and Rustichini, A.: 1994, Unawareness: a Formal Theory of Unforeseen Contingencies, CORE DP.
- Rubinstein, A., Wolinsky, A. (1990) On the Logic of “Agreeing to Disagree” Type Results. Journal of Economic Theory 51: pp. 184-193
- Samet, D. (1990) Ignoring Ignorance and Agreeing to Disagree. Journal of Economic Theory 52: pp. 190-207
- Dalen, D. (1983) Logic and Structure. Springer-Verlag, New York-Berlin-Tokio
- Awareness and partitional information structures
Theory and Decision
Volume 37, Issue 1 , pp 107-124
- Cover Date
- Print ISSN
- Online ISSN
- Kluwer Academic Publishers
- Additional Links
- negative introspection
- Kripke structures
- modal propositional logic
- Industry Sectors