 The identity-conditions of a whole often depends upon facts about its parts. When are two substantial facts \([R; a, b]\) and \([S; c, d]\) identical? A plausible answer is: when \(R = S, a = c\) and \(b = d\). This answer has consequences for a friend of Modal Criterion. Accepting both the proposed identity-condition and Modal Criterion, one cannot claim that there are distinct but necessarily coextensive properties (which are part of some facts), or that the facts [being human; Socrates] and [having a human member; [Socrates]] are distinct, even on the plausible assumption that they exist in the very same worlds.