Semantics and Ontology: On the Modal Structure of an Epistemic Theory of Meaning

In this paper I shall confront three basic questions.
First, the relevance of epistemic structures, as formalized
and dealt with by current epistemic logics, for a
general Theory of meaning. Here I acknowledge M. Dummett"s
idea that a systematic account of what is meaning of
an arbitrary language subsystem must especially take into
account the inferential components of meaning itself. That
is, an analysis of meaning comprehension processes,
given in terms of epistemic logics and semantics for epistemic
notions.
The second and third questions relate to the ontological
and epistemological framework for this approach.
Concerning the epistemological aspects of an epistemic
theory of meaning, the question is: how epistemic logics
can eventually account for the informative character of
meaning comprehension processes. "Information� seems
to be built in the very formal structure of epistemic processes,
and should be exhibited in modal and possibleworld
semantics for propositional knowledge and belief.
However, it is not yet clear what is e.g. a possible world.
That is: how it can be defined semantically, other than by
accessibility rules which merely define it by considering its
set-theoretic relations with other sets-possible worlds.
Therefore, it is not clear which is the epistemological status
of propositional information contained in the structural
aspects of possible world semantics. The problem here
seems to be what kind of meaning one attributes to the
modal notion of possibility, thus allowing semantical and
synctactical selectors for possibilities. This is a typically
Dummett-style problem.
The third question is linked with this epistemological
problem, since it is its ontological counterpart. It concerns
the limits of the logical space and of logical semantics for a
of meaning. That is, it is concerned with the kind of
structure described by inferential processes, thought, in a
fregean perspective, as pre-conditions of estentional
treatment of meaning itself. The second and third questions
relate to some observations in Wittgenstein"s Tractatus.
I shall also try to show how their behaviour limits the
explicative power of some semantics for epistemic logics
(Konolige"s and Levesque"s for knowledge and belief).