An Epistemic Theory of Deductive Arguments

Epistemic logic and the theory of argumentation have only

very recently started to interact, despite the central role

that the epistemic view of argument plays in contemporary

epistemology. In this paper, we present a novel epistemic

language for reasoning about three types of beliefs of

agents: explicit belief, plain implicit belief, and focused

implicit belief. We use it to represent the concept of

deductive argument and to elucidate its connection with the

concept of belief. Our language is interpreted through a

formal semantics that relies on belief bases.

This semantics allows us to naturally represent the reasons

an agent has for believing something, which we show to be

closely related to the notion of argument. We provide

results on expressiveness, axiomatization and decidability

for the language.