Helmut,
In every version of language and logic -- ancient or
modern, informal or formal -- the intensional definition is fundamental.
It corresponds to the definition you'll find in a typical dictionary of
any natural language or in any formal specification in science,
engineering, business,
John,
yes, but isn´t it so, that in mathematics and symbolic logic, if the extension is known i.e. covered by proofs, an intensional term can be equivalent with an extensional one, and this is called "classical logic"? That is, if I am right, that e.g. "NOT (A AND NOT B)" is extensional, and
