In this introduction to the special issue “40 years of FDE”, we offer an overview of the field
and put the papers included in the special issue into perspective. More specifically, we first …

Reasoning about knowledge—particularly the knowledge of agents who reason about the
world and each other's knowledge—was once the exclusive province of philosophers and …

It is argued that a sophisticated question-answering machine that has the capability of
making inferences from its data base should employ a certain four-valued logic, the …

The purpose of the present paper is to suggest a new way of handling the logical paradoxes.
Instead of trying to dissolve them, or explain what has gone wrong, we should accept them …

Notice that, despite its familiarity,(V) does not give us a complete account of logical
consequence. To construct a logic we need an accurate and systematic account of which …

I propose that a certain four-valued logic should sometimes be used. It is to be understood
that I use “logic” in a narrow sense, the old sense: a logic as an organon, a tool, a canon of …

Paraconsistent logics are those which permit inference from inconsistent information in a
non-trivial fashion. Their articulation and investigation is a relatively recent phenomenon …

The latter half of the 20th Century witnessed an 'intensional revolution': a great collective
effort to analyse notions which are absolutely fundamental to our understanding of the world …

At first the champions of relevance in logic taught that relevance and preservation of truth
were two separate merits, equally required of any relation that claims the name of …

I formulate a Gentzen consecution calculus for an indefinite number of logics all mixed
together, including boolean (two valued), intuitionistic, relevance, and (various) modal …