Single Idea 10755

[catalogued under 5. Theory of Logic / K. Features of Logics / 5. Incompleteness]

Full Idea

No deductive system is semantically incomplete in and of itself; rather a deductive system is incomplete with respect to a specified formal semantics.

Gist of Idea

A deductive system is only incomplete with respect to a formal semantics

Source

Marcus Rossberg (First-order Logic, 2nd-order, Completeness [2004], §3)


A Reaction

This important point indicates that a system might be complete with one semantics and incomplete with another. E.g. second-order logic can be made complete by employing a 'Henkin semantics'.