Lately the conception of natural selection has been broadened, by Haeckel, in particular, and the variation of species has been shown to be the result of actual change owing to adaptation and inheritance, whereby adaptation is considered as the source of variations and heredity as the conserving element in the process. Even this is not correct in Herr Duehring's eyes. "Peculiar adaptation to the circumstances of life as they are offered or withheld by nature supposes impulses and facts which answer to the conception. Hence adaptation is only apparent and actual causality does not elevate itself above the lowest steps of physical, chemical and plant physiology." It is again the name which provokes Herr Duehring. But how does he deal with the matter? The question is if such changes do take place in the species of organic beings or not. And again Herr Duehring has no reply. "If a plant in the course of its growth takes a direction by which it gets the most light the result is nothing but a combination of physical forces and chemical agents, and if we are to call it an adaptation, not metaphorically but strictly, confusion is certain to arise in the motion." This man is so exacting with other people because he is quite well acquainted with the intentions of nature and speaks of the subtlety of nature, even of its will. There is confusion, indeed, but with whom, with Haeckel or with Herr Duehring? And the confusion is not only spiritual but logical. We have seen that Herr Duehring put forth all his efforts to make the purpose idea in nature real. "The relation of means and end does not by any means show a conscious intention." But what is adaptation without conscious intention, without any intrusion of design of which he complains so loudly, but an unconscious teleology?