more from M Fitting/R Mendelsohn

Single Idea 13730

[catalogued under 9. Objects / F. Identity among Objects / 7. Indiscernible Objects]

Full Idea

Equality has caused much grief for modal logic. Many of the problems, which have struck at the heart of the coherence of modal logic, stem from the apparent violations of the Indiscernibility of Identicals.

Gist of Idea

The Indiscernibility of Identicals has been a big problem for modal logic


M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 7.1)

Book Reference

Fitting,M/Mendelsohn,R: 'First-Order Modal Logic' [Synthese 1998], p.141

A Reaction

Thus when I say 'I might have been three inches taller', presumably I am referring to someone who is 'identical' to me, but who lacks one of my properties. A simple solution is to say that the person is 'essentially' identical.

Related Idea

Idea 13726 Counterpart relations are neither symmetric nor transitive, so there is no logic of equality for them [Fitting/Mendelsohn]