In epistemic logic, some axioms dealing with the notion of knowledge are rather convoluted and it is difficult to give them an intuitive interpretation, even if some of them, like .2 and .4, are considered by some epistemic logicians to be key axioms. We show that they can be characterized in terms of understandable interaction axioms relating knowledge and belief. In order to show it, we first...

“There is no need for us to emphasize either the fact that meaning is the crucial feature of language or the fact that it is the most intractable problem of linguistics. Semantics, the study of meaning, has a long and eminently respectable history as an activity for philosophers, logicians, grammarians, philologists and linguists, but unfortunately the obviousness of meaning of words and discou...

We identify a class of paradoxes that are neither set-theoretical or semantical, but that seem to depend on intensionality. In particular, these paradoxes arise out of plausible properties of propositional attitudes and their objects. We try to explain why logicians have neglected these paradoxes, and to show that, like the Russell Paradox and the direct discourse Liar Paradox, these intensiona...

Logic as a single, unified academic discipline does not exist today. To be a logician today, you need to train as a mathematician, philosopher or computer scientist. Not only will you need to master topics that might be peripheral to your main area of interest, but you will have less and less in common with fellow logicians working in other disciplines. Eventually you may even lose touch with t...

In this paper I discuss what, according to my long experience, every computer scientist should know from logic. We concentrate on issues of modeling, interpretability and levels of abstraction. We discuss what the minimal toolbox of logic tools should look like for a computer scientist who is involved in designing and analyzing reliable systems. We shall conclude that many classical topics dear...

We attempt to address here some alleged criticisms against the philosophical import of the so-called Brazilian approach to paraconsistency, especially by providing some demanded epistemic elucidations to the whole enterprise of the logics of formal inconsistency. In the way of elucidating, we substantiate the view that difficulties in reasoning under contradictions in both the Buddhist and the ...

The newly emerging branch of research of Computer Science received encouragement from the successors of the Warsaw mathematical school: Kuratowski, Mazur, Mostowski, Grzegorczyk, and Rasiowa. Rasiowa realized very early that the spectrum of computer programs should be incorporated into the realm of mathematical logic in order to make a rigorous treatment of program correctness. This gave rise t...

There are two reasons why medieval logic is of interest to modern logician: One is to see how similar it is to modern logic and the other is to see how different it is. We study three 13th-century works on modal logic and give two examples their views of modal logic differ from modern views of the same: the nature of modality and the truth conditions for modal sentences. Because of the differen...

according to the rules of quadruplet relations between concepts, muslim logicians have proved that relation between the negations of two concepts which are equal (musawi) or absolute-general-and-specific (‘amm wa khas-e mutlaq) are, respectively, equal and absolute-specific-and-general; but these rules come across some problems when the most inclusive concepts are involved, since the negation o...

After a critical review of the present architecture of SNOMED CT, addressing both logical and ontological issues, we present a roadmap towards an overall improvement of this terminology. In particular, we recommend the following actions: Upper level categories should be rearranged according to a standard upper level ontology. Meta-class like concepts should be identified and removed from the ta...