Towards a Hybrid Logic of Acquaintance and Awareness
A. Saffiotti and F. Sebastiani
A (partial) solution to the well-known problem of "logical omniscience"
in modal-like logics for knowledge and belief is suggested; it is based
on the notion of "awareness of a proposition" and on that of "explicit
belief", viewed as "classical" belief modulo awareness. Our formal
treatment relies on the idea that an agent is aware of a proposition s
iff he is "capable of attributing a meaning to s": this idea has lead us
to develop a logic for belief where the fact that an agent is aware of a
proposition may be characterized in terms of the "terminological
content" of the proposition. Following the introduction of the
awareness requirement, our notion of explicit belief does not suffer
from logical omniscience: in particular, it is not closed with respect
to logical equivalence and "valid implication". We argue that this is a
useful feature when such logics are applied to e.g. dialogue modelling
and, in general, to the specification of intelligent rational agents.