There are two logical laws that G.W. Leibniz formulated and held:
(1) The Indiscerniblility of Identicals: If x and y are identical, then they have all the same properties.
(2) The Identity of Indiscernibles: If x and y have all the same properties, then they are identical.
The first is pretty uncontroversial, I’ve yet to meet anyone that denies it. All it really says that if you compare something with itself, it will have all the same properties as itself.
