The term entelechy was first introduced into philosophy by Aristotle who used it in several different but related senses. We shall understand by it an intrinsic tendency within a physical body, by virtue of which it is orientated towards some goal, e.g., the perfection of the individual concerned or of the species to which it belongs. The principle of entelechy is sometimes known as the principle of finality or teleology.

The question whether there is intrinsic finality in the physical world has been much disputed. Aristotle and most of the medieval philosophers h…