In epistemic logic, some axioms dealing with the notion of knowledge are rather convoluted and difficult to interpret intuitively, even though some of them, such as the axioms.2 and.3, are considered to be key axioms by some epistemic logicians. We show that they can be characterized in terms of understandable interaction axioms relating knowledge and belief or knowledge and conditional belief. In order to show it, we first sketch a theory dealing with the characterization of axioms in terms of interaction (...) axioms in modal logic. We then apply the main results and methods of this theory to obtain specific results related to epistemic and doxastic logics. (shrink)

Ivan Boh affirms and Robert Pasnau denies that William Heytesbury holds merely true belief to be sufficient for knowledge in the broad sense. I argue that Boh is correct and Pasnau is mistaken, and that there is a long-running orthodox medieval tradition agreeing with Heytesbury about the conditions for knowledge. I offer a hypothesis about the origins, continuance and demise of that medieval tradition, and some remarks about the tradition's significance.

Epistemic minimalism affirms that mere true belief is sufficient for propositional knowledge. I construct a taxonomy of some specific forms of minimalism and locate within that taxonomy the distinct positions of various advocates of minimalism, including Alvin Goldman, Jaakko Hintikka, Crispin Sartwell, Wolfgang Lenzen, Franz von Kutschera, and others. I weigh generic minimalism against William Lycan’s objection that minimalism is incompatible with plausible principles about relations between knowledge, belief, and confidence. I argue that Lycan’s objection fails for equivocation but that (...) some specific forms of minimalism are better able than others to articulate that defense. (shrink)

In this paper, I develop a new set of doxastic logical systems and I show how they can be used to solve several well-known problems in doxastic logic, for example the so-called problem of logical omniscience. According to this puzzle, the notions of knowledge and belief that are used in ordinary epistemic and doxastic symbolic systems are too idealised. Hence, those systems cannot be used to model ordinary human or human-like agents' beliefs. At best, they can describe idealised individuals. The (...) systems in this paper can be used to symbolise not only the doxastic states of perfectly rational individuals, but also the beliefs of finite humans. Proof-theoretically, I will use a tableau technique. Every system is combined with predicate logic with necessary identity and ‘possibilist’ quantifiers and modal logic with two kinds of modal operators for relative and absolute necessity. The semantics is a possible world semantics. Finally, I prove that every tableau system in the paper is sound and complete with respect to its semantics. (shrink)

On the basis of a ten-place comparative value relation, artificially reduced to a binary relation, some human value structures are studied and a concept of value kinematics is proposed. A miniature value logic is outlined, making it possible with precision to handle several explicated value notions and to analyze interrelations between them. Finally, the question is discussed whether health can be said to be an absolute and an intrinsic value.