Anselmic Vinegar

Anselm of Canterbury (1033 – 1109), saint. He's the 'nothing greater than which can be conceived' guy:

Ergo domine...credimus te esse aliquid quo nihil maius cogitari possit 'Therefore, lord...we believe that you are something than which nothing greater can be thought.' Proslogion, ch. 2 [Gregory Schufreider Confessions of a Rational Mystic: Anselm's Early Writings (West Lafayette, Ind.: Purdue University Press, 1994) pp. 324-5]

It's never been clear to me how coherent this sort of value-judgment limit case can ever be.  For instance:

'God was conceived of a most pure Virgin ... it was fitting that the virgin should be radiant with a purity so great that a greater purity cannot be conceived' [quoted in Mary for Earth and Heaven: Essays on Mary and Ecumenism, 2002, William McLaughlin, Jill Pinnock, eds.]

But Mary was alive; and any alive individual contains within him/her the possibility that they could, at a future state, act in an impure way.  Therefore it is possible to conceive a greater purity ... for instance, if Mary had been in a lifelong coma, or dead, when she conceived and gave birth.  Or: flesh is inherently less pure, in teh sense of being more corruptible, than diamond; accordingly I can conceive of a Mary constructed (like that X-Men:First Class character) entirely out of diamond.  It doesn't matter that this isn't very likely; the criterion is not likelihood, but conceivability, and I can conceive it.