 Take the set of nuclear properties, {being golden, being a mountain}. By (P1) and (P2), some unique object has exactly the two nuclear properties in the set. That object is the golden mountain. Take another set of nuclear properties, {being square, being round}, and the two principles give us the round square. Both of these objects are radically incomplete; they have no weight, height, shape, or size, for example. The need for distinguishing nuclear properties from extra-nuclear properties is readily seen by considering the set, {being golden, being a mountain, being existent}. If (P2) is to apply to such a set, it should yield an object having the three properties in the set. Such an object is golden, a mountain, and existent, that is, it is a golden mountain which exists. So it should be true that a golden mountain exists, but it is in fact not true. Parsons defines a possible object as an object such that it is possible that there exist an object having all of its nuclear properties. On this conception, all existing objects are possible objects, some golden mountains are possible objects, and the round square is not a possible object. It is worth noting that in Parsons’ theory, negation needs to be handled delicately (Parsons 1980: 19–20, 105–06, Zalta 1988: 131–34). Take the set, {being round, being non-round}. By (P2), we have an object, x, which is round and non-round. So, x is non-round. If we can infer from this that it is not the case that x is round, then we should be entitled to say that x is round and it is not the case that x is round, which is a contradiction. Thus, we should not be allowed to infer ‘It is not the case that x is round’ from ‘x is non-round’.