Частичные эпистемические логики и «случайные» тождества.

Abstract

The article deals with some difficulties which arise in norm al m odal predicate systems with identity (based on standard sem antics o f possible worlds). In such systems we can derive some theorems which, under the intended interpretation, are intuitively unacceptable. One o f them says: every true statem ent o f identity is necessarily true, or, in other words, there are no true contingent statements o f identity. Such theorems seem more unacceptable when we interpret the necessity operator epistemically as ‘som eone knows that... ’ It is shown that difficulties o f such kind do not arise in partial epistemic m odal systems with identity (based on semantics o f partial possible worlds), and no assertions o f the above-m entioned kind are provable in them.