‘As every instrument and every bodily member subserves some partial end, that is to say, some special action, so the whole body must be destined to minister to some plenary sphere of action. Thus the saw is made for sawing, since sawing is a function, and not sawing for the saw. Similarly, the body too must somehow or other be made for the soul, and each part of it for some subordinate function to which it is adapted.’[22] [21] I have somewhat abbreviated this and the previous sentence. [22] _De partibus animalium_, i. 5; 644ᵇ 21. Aristotle is, in the fullest sense a ‘vitalist’. He believes that the presence of a certain peculiar principle of a non-material character is essential for the exhibition of any of the phenomena of life. This principle we may call _soul_, translating his word ψυχή. Living things, like all else in nature, have, according to Aristotle, an end or object. ‘Everything that Nature makes,’ he says, ‘is means to an end. For just as human creations are the products of art, so living objects are manifestly the products of an analogous cause or principle.... And that the heaven, if it had an origin, was evolved and is maintained by such a cause, there is, therefore, even more reason to believe, than that mortal animals so originated. For order and definiteness are much more manifest in the celestial bodies than in our own frame.’[23] It was a misinterpretation of this view that especially endeared him to the mediaeval Church and made it possible to absorb Aristotelian philosophy into Christian theology. It must be remembered that the cause or principle that leads to the development of living things is in Aristotle’s view, not external but _internal_. While putting his own view Aristotle does not fail to tell us of the standpoint of his opponents. ‘Why, however, it must be asked, should we look on the operations of Nature as dictated by a final cause, and intended to realize some desirable end? Why may they not be merely the results of necessity, just as the rain falls of necessity, and not that the corn may grow? For though the rain makes the corn grow, it no more occurs in order to cause that growth, than a shower which spoils the farmer’s crop at harvest-time occurs in order to do that mischief. Now, why may not this, which is true of the rain, be true also of the parts of the body? Why, for instance, may not the teeth grow to be such as they are merely of necessity, and the fitness of the front ones with their sharp edge for the comminution of the food, and of the hind ones with their flat surface for its mastication, be no more than an accidental coincidence, and not the cause that has determined their development?’[24] [23] _De partibus animalium_, i. 1; 641ᵇ 12. [24] _Physics_, ii. 8, 3; 198ᵇ 6. This passage is considerably abbreviated and slightly paraphrased.