Single Idea 6048

[catalogued under 9. Objects / F. Identity among Objects / 8. Leibniz's Law]

Full Idea

Leibniz's Law, which a defender of relative identity might opt to reject, is so fundamental to the notion of identity that rejecting it amounts to changing the subject.

Clarification

The Law says two truly identical things must have the same properties

Gist of Idea

Leibniz's Law is so fundamental that it almost defines the concept of identity

Source

Colin McGinn (Logical Properties [2000], Ch.1 n8)

Book Reference

McGinn,Colin: 'Logical Properties' [OUP 2003], p.5


A Reaction

The Law here is the 'indiscernibility of identicals'. I agree with McGinn, and anyone who loses their grip on this notion of identity strikes me as losing all grip on reality, and threatening their own sanity (well, call it their 'philosophical sanity').