Posted By:
Jason LIf there are 3 PSA 9's out there of a certain card, and one is liberated from its holder somewhere during its travels, then there are only 2 PSA 9's out there.
It could be that a certain card only appears in nature in mint condition, but it's not a PSA 9 unless PSA says so. That is the essence of what you are paying for in a grading service
of course, to get more existential about it, I suppose that if beauty is in the eye of the beholder, every card is perfect for somebody, regardless of condition, and then we may be forced to say that the number of mint cards is infinite, and therefore unknowable? Hey, I think the value of my pitiful little collection just became priceless!!! I like this 
(edited to add last paragraph)