Friendliness for logicians
David Makinson · London School of Economics and Political Science Research Online (London School of Economics and Political Science) · 2005
We define and examine a notion of logical friendliness, which is a broadening of the familiar notion of classical consequence. The concept is studied first in its simplest form, and then in a syntax-independent version, which we call sympathy. We also draw attention to the surprising number of familiar notions and operations with which it makes contact, providing a new light in which they may be seen.