  In his (1980), Peter Unger introduced the “Problem of the Many”. A similar problem appeared simultaneously in P. T. Geach (1980), but Unger's presentation has been the most influential over recent years. The problem initially looks like a special kind of puzzle about  vague predicates,  but that may be misleading. Some of the standard solutions to  Sorites paradoxes  do not obviously help here, so perhaps the Problem reveals some deeper truths involving the metaphysics of material constitution, or the logic of statements involving identity.