Driesch describes it as a rudimentary feeling and willing, a ‘psychoid’, ‘morphaesthetic’ or perceptive of that form which is the desired end towards which it controls and directs all the material elements of differentiation, like the grain of wheat of Treviranus, dreaming dimly of its destiny. It is thus a _vera causa_--an unconditional and invariable antecedent--a psychical factor which can intervene in the purely physical series of causes and effects, and for it he revives the Aristotelian term ‘Entelechy’. Such is the ‘vitalism’ introduced by Hans Driesch, a teleological theory clearly, but no mere metaphysical doctrine of final causes: rather a dynamic teleology which not only sees an end in every organic process, but postulates an immaterial entity to guide the merely mechanical forces towards the realization of that end. Such a theory is open to very serious criticism from both the scientific and the philosophical side. But before we pass to that criticism let us turn aside to examine some of the other aspects under which the Proteus of Vitalism presents himself. Thus the modern physiologist Bunge, while owning that it would be a lack of intelligence to expect to make with our senses discoveries in living nature of a different order to those revealed to us in inorganic nature, yet insists that we must transfer to the objects of our sensory perception, to the organs, to the tissue elements, and to every minute cell, something which we have acquired from our own consciousness, something, that is to say, which is not motion, and is not in space, but is in time only. The essence of vitalism, so Bunge would have it, lies in starting from what we know, the internal world, to explain what we do not know, the external world. We can only remark that this position appears to rest upon an epistemological confusion, for Bunge has evidently failed to distinguish between the idealism which teaches that the world of nature, including our own bodies, only exists in so far as it is an object of knowledge, that reality is ultimately ideal, and the ‘animism’ which, as we have seen, gives every object, at least every living object, in nature a directive consciousness of its own. The former does not lie immediately within the scope of the present inquiry; the latter we shall have occasion to discuss again.