To what precisely do we refer when we designate three persons as “men”? We
refer to the fact that they are living beings who possess the same
characteristic distinguishing them from all other living species: a rational
faculty—though the specific measurements of their distinguishing
characteristic qua men, as well as of all their other characteristics qua
living beings, are different. (As living beings of a certain kind, they
possess innumerable characteristics in common: the same shape, the same range
of size, the same facial features, the same vital organs, the same
fingerprints, etc., and all these characteristics differ only in their
measurements.)