The idea originated in a comparison between Humanity and Animality.

It is a mistake to suppose that the great dispute which has lately made a stir, between Cuvier and Geoffroi Saint-Hilaire, arose from a scientific innovation.  Unity of structure, under other names, had occupied the greatest minds during the two previous centuries.  As we read the extraordinary writings of the mystics who studied the sciences in their relation to infinity, such as Swedenborg, Saint-Martin, and others, and the works of the greatest authors on Natural History—­Leibnitz, Buffon, Charles Bonnet, etc., we detect in the monads of Leibnitz, in the organic molecules of Buffon, in the vegetative force of Needham, in the correlation of similar organs of Charles Bonnet—­who in 1760 was so bold as to write, “Animals vegetate as plants do”—­we detect, I say, the rudiments of the great law of Self for Self, which lies at the root of Unity of Plan.  There is but one Animal.  The Creator works on a single model for every organized being.  “The Animal” is elementary, and takes its external form, or, to be accurate, the differences in its form, from the environment in which it is obliged to develop.  Zoological species are the result of these differences.  The announcement and defence of this system, which is indeed in harmony with our preconceived ideas of Divine Power, will be the eternal glory of Geoffroi Saint-Hilaire, Cuvier’s victorious opponent on this point of higher science, whose triumph was hailed by Goethe in the last article he wrote.

I, for my part, convinced of this scheme of nature long before the discussion to which it has given rise, perceived that in this respect society resembled nature.  For does not society modify Man, according to the conditions in which he lives and acts, into men as manifold as the species in Zoology?  The differences between a soldier, an artisan, a man of business, a lawyer, an idler, a student, a statesman, a merchant, a sailor, a poet, a beggar, a priest, are as great, though not so easy to define, as those between the wolf, the lion, the ass, the crow, the shark, the seal, the sheep, etc.  Thus social species have always existed, and will always exist, just as there are zoological species.  If Buffon could produce a magnificent work by attempting to represent in a book the whole realm of zoology, was there not room for a work of the same kind on society?  But the limits set by nature to the variations of animals have no existence in society.  When Buffon describes the lion, he dismisses the lioness with a few phrases; but in society a wife is not always the female of the male.  There may be two perfectly dissimilar beings in one household.  The wife of a shopkeeper is sometimes worthy of a prince, and the wife of a prince is often worthless compared with the wife of an artisan.  The social state has freaks which Nature does not allow herself; it is nature plus society.  The