ABSTRACT
Philosophy and common sense have long agreed about the uniqueness of individual man. Science makes it a trio of concordant voices, for the uniqueness of individual mice and men is a proposition which science can demonstrate with equal force, perhaps with deeper cogency, and certainly with a hundred times as much precision. The differences between individuals are combinational, or, as mathematicians say, combinatorial differences; one individual differs from all others philosophers because he has unique endowments but because he has a unique combination of endowments. Only inborn diversity, and a genetical system which keeps that diversity permanently in being, it is a mere truism that if inborn diversity and genetic individuality were to be extinguished, as in some animals they can be, by inbreeding, then selection would have nothing to act on, and the species would be left without evolutionary resource.
