Full Idea
The cat is 'Tibbles' with a tail; 'Tib' is Tibbles after the loss of the tail. 1) Tibbles isn't Tib at t; 2) Tibbles is Tib at t'; 3) Tibbles at t is Tibbles at t'; 4) Tib at t is Tib at t'; so 5) Tibbles at t is Tib at t (contradicting 1). What's wrong?
Gist of Idea
Does Tibbles remain the same cat when it loses its tail?
Source
Peter Simons (Parts [1987], 3.3)
Book Reference
Simons,Peter: 'Parts: a Study in Ontology' [OUP 1987], p.119
A Reaction
[The example is in Wiggins 1979, from Geach, from William of Sherwood] Simons catalogues nine assumptions which are being made to produce the contradiction. 1) rests on Leibniz's law. Simons says two objects are occupying Tibbles.