universal affirmative proposition to the extent that there is a necessary connection between "man" and "mortal." That is, a universal proposition ("all men are mortal") states that all members of a class (men) carry a further designation (mortality). (A particular proposition holds only that some members of a class have that particular designation).
Universality as a metaphysical notion further holds to the extent that the proposition is true for all times and places. "2+2=4" is a universal proposition in this sense. Its truth doesn't change if you're in medieval Calcutta, ancient Rome, or modern Dekalb.
But, although long considered universal both logically and metaphysically, the proposition "all men are mortal" may not really be true. For one thing, developments in genetics and cellular biology suggest new possibilities for extending life, even indefinitely. Other developments in artificial intelligence suggest a transformed notion of life and immortality in which one could upload human consciousness to virtual bodies.
It's curious to think of this proposition above all as a black swan. If "all men are mortal," that well-worn absolute certainty of Intro to Logic, is simply a false, formally universal proposition, what does this say about universal propositions or metaphysical universality? I also wonder what this does to the central proposition of most Asian religions - but specifically the religions of Tibet, Nepal, and India - that everything that lives, dies.