“The very idea of absolute perfection is in every way self-contradictory… the dead is not perfect because it does not live.”
It seems to me that, for Mises, “perfection” is simply the perfection of an acting entity, perfection as a state that someone acting (in a human way) could or could not experience or at least conceive. It’s a book on human action, after all, so “the perfection of a pinball machine” would be just irrelevant and empty mental concept, as vapid as “perfection of the flying spaghetti monster”.
So “perfection in death” seems to stand outside of his very definition of the word “perfection” as used in the book. At least, that’s how I read it.
And, of course, a living person can not be perfect, even if our state would somehow miraculously become perfect for a millisecond, because life itself (us being alive) would push us out of it. We would need to become non-living to make life stop pushing us out of being perfect, but then we would be pushed out of the very definition of “perfection” by not being alive (to be human actors, if needed). So we can’t win, alas. The whole thing seems to boil down simply to “life on earth is, for humans, never perfect”.
This would also mean that the only way for, for example Buddhist monks, to potentially reach such “perfection”, would be to leave “human life on earth” by acting in a non-human way, that is, by living some fundamentally different life while staying alive on earth. Of course, they might potentially reach some other kind of perfection by simply dying to earth, but Mises wouldn’t care to cover that option, so he delineated his concept of “perfection” accordingly. At least, that’s how I read the book.