With Leibniz Law so restricted there is no problem with Harry in the summer being the same person as Harry in the winter. Both are tanned when summer is present and both are not tanned when winter is present. She has 10,000 hairs. A moment later little Tommy plucks a hair from Tibbles back. The transitivity of identity tells us that for any objects x , y , and z , if x and y are identical and y and z are identical, then x and z are identical.
Transitivity is lost.
Tibbles the cat and a certain piece of feline tissue. According to Geach, identity is sortal relative. Objects x and y may be identical relative to one sortal, but not identical relative to another. According to this theory, x and y are identical as cat , but x and y are not identical as piece of feline tissue . That thing is both a cat and a piece of feline tissue.