The aim of the present paper is to introduce a system, where the epistemic state of an agent is represented truth-functionally. In order to obtain this system, we propose a four-valued logic, that we call the logic of rational agent, where the fact of knowing something is formalized at the level of valuations, without the explicit use of epistemic knowledge operator. On the basis of this semantics, a sound and complete system with two distinct truth-functional negations is provided. These negations (...) allow us to express the statements about knowing or not knowing something at the syntactic level. Moreover, such a system is applied to the analysis of knowability paradox. In particular, we show that the paradox is not derivable in terms of the logic of rational agent. (shrink)

In this paper, I attempt to offer a general outline of my views on the origin and evolution of language. I do not pretend in any way to a completely new conception of language evolution. It seems to me that all the most important and productive hypotheses about the origin of language have already been made before, and it is only a matter of putting the pieces of the puzzle together correctly. As far as I can see it, the evolution (...) of language is directly related to the embedded and embodied emotional types, which served as the basis for the subsequent categorization of perceived objects, and thus laid the ground for the formation of first an internal language (of thought), and then an external verbal language. Consistent with this, the paper is organized as follows. In the Introduction I briefly describe the problem I am facing in this article and outline a plan for solving it. Next section comprises a survey of relevant empirical findings related primarily to the processing and understanding of abstract terms and concepts. In my view, it supports the idea of the close connection of abstract terms proceeding, and thus language comprehension, with emotional states. The third section provides relevant theoretical considerations of the relationship between emotions, cognition, and language. Consistently considering various theories of emotions and concepts of language formation, I pay attention to the connection between affective states and language as a sign system. In the fourth section, my views are presented directly. In so doing, I illustrate my approach with a telling example that shows how, in the course of evolution, embedded and embodied emotional responses and reactions could become the building blocks first for the internal language of thought, and then for the external natural language. (shrink)