On notions of assertion, knowledge and opinion in epistemic logic Cover Image

On notions of assertion, knowledge and opinion in epistemic logic
On notions of assertion, knowledge and opinion in epistemic logic

Author(s): Edward Nieznański
Subject(s): Philosophy
Published by: Wydawnictwo Naukowe Uniwersytetu Kardynała Stefana Wyszyńskiego w Warszawie
Keywords: epistemic logic; belief; truth

Summary/Abstract: In the article there is presented a formalized theory in frame of which there are compared three stages of convictions (S – I am (firmly) convinced, D – I admit, P - I suppose), W operator understood as “I know, that” and M operator reads as “I believe, that”. The theory is characterized both on syntactic and semantic level. In frame of a syntactic description there are noticed certain logical square connections between S and D, e.g.: S(p) is contrary to D(Np) and S(p) is opposite to S(Np). S(Np) is contrary to D(p). Expressions: D(p) and D(Np) are sub-opposite. Operators P and S are introduced axiomatically. Operators D, W, and M are characterized by definitions, which are understood in the following way: Def 1: I admit, that p iff I am not firmly convinced, that not–p Def 2: I know, that p iff p and I am firmly convinced, that p Def 3: I believe, that p iff I suppose that p and I admit, that not–p. On semantic level we consider a structure (T, <, ≤ ), where T is a set of time points, < is a relation of being earlier than, and ≤ is a relation of being not later than.

  • Issue Year: 47/2011
  • Issue No: 4
  • Page Range: 73-83
  • Page Count: 11
  • Language: English