the link between one organic structure and another can no longer, in fact, be the identity of one or several elements, but must be the identity of the relation between the elements (a relation in which visibility no longer plays a role) and of the functions they perform; moreover, if these organic structures happen to be adjacent to one another, on account of a particularly high density of analogies, it is not because they occupy proximate places within an area of classification; it is because they have both been formed at the same time, and the one immediately after the other in the emergence of the successions.