more from Frank P. Ramsey

Single Idea 13427

[catalogued under 5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic]

Full Idea

In 'a = b' either 'a' and 'b' are names of the same thing, in which case the proposition says nothing, or of different things, in which case it is absurd. In neither case is it an assertion of a fact; it only asserts when a or b are descriptions.

Gist of Idea

Either 'a = b' vacuously names the same thing, or absurdly names different things

Source

Frank P. Ramsey (The Foundations of Mathematics [1925], 1)

Book Reference

Ramsey,Frank: 'Philosophical Papers', ed/tr. Mellor,D.H. [CUP 1990], p.179


A Reaction

This is essentially Frege's problem with Hesperus and Phosphorus. How can identities be informative? So 2+2=4 is extensionally vacuous, but informative because they are different descriptions.