Herbert Paul Grice and Peter Thomas Geach on relative identity

Speranza

Strictly, it's best to refer to Grice's theory as Grice's and Myro's theory of relative identity -- as does Grice in "Prejudices and recollections, which become the life and opinions of Paul Grice".

The Grice-Myro theory of identity is relative. Or rather, it is a theory of relative identity.

It is best formalised by Myro in his System G_HP.

Geach's theory of relative identity has not been formalised.

The source for Grice's theory is Wiggins on Substance, rather.