One of the fundamental empirical concepts of the science of economics is that of economic society, which is formed by abstracting certain classes of economic relationships from the mass of relationships of all kinds among which the life of the individual realizes itself. Any treatise of economics can be considered as a definition of economic society; and we know how those definitions are apt to vary according to the choice of the groups of facts studied, and the method employed, by different schools of economists. The economic society of the Marxian is not the economic society of the classical economist; the Catholic economist, differing from both, will include in his treatment the consideration of certain ethical relations which give a greater complexity to his scheme. It would be possible to study the economics of the individual in perfect isolation from all other human beings, limiting the elements of this particular form of society to one man, and that portion of nature from which he draws his food, his clothing, his shelter; on the other hand, the whole of mankind and the whole of nature may enter into a single, all-including, economic body. We may even study animal species, in their relations within themselves, or with man, or with other animal species, or with nature at large, from an economic standpoint (symbiosis and parasitism are facts bearing a close resemblance with human economy)--and thus form an infinite number of new economic societies. Each of these empirical concepts can be varied _ad infinitum_, by the mere inclusion or exclusion of certain classes of relationships. The empirical, non-rigorous character of the concept of economic society is self-evident; and it can therefore be usefully employed to prove by analogy the similar character of the concept of society as manufactured by jurists, sociologists, and political scientists. It is against such fictions that philosophy reacts by building a concept of the isolated individual, that is, of the individual isolated from the particular classes of relationships which enter into the formation of particular empirical concepts of society; but it does this only to plunge the individual again in the midst of that infinite multiplicity, which is one aspect, and an essential one, of reality, Society as a philosophical concept cannot be identified with any form of economic or political society; of such, as mere abstractions, no philosophical treatment is possible. Society is that real multiplicity, without which we should have neither knowledge nor action, neither art nor thought, neither utility nor morality; and from society in this sense, the individual cannot be isolated, without reducing him, in his turn, to a merely abstract concept.