In the middle of them all, compressed within the circle they form, man is designated more, required by them, since it is he who speaks, since he is seen to reside among the animals (and in a position that is not merely privileged, but a source of order for the totality they form: even though he is not conceived as the end product of evolution, he is recognized to be one extremity of a long series), and since, lastly, the relation between his needs and the means he possesses to satisfy them is such that he is necessarily the principle and means of all production.