Physiological Introduction or Principles of the Human Body

the soul. Therefore, it is evident that a living human body has as its substantial form a substantial life, or soul, and indeed a rational one; for the vegetative soul alone is the form of plants, and the sensitive soul alone, insofar as it includes the vegetative, is the form of brutes. Therefore, the form of man will be solely rational, yet possessing eminently the power, in a body duly disposed, to also vegetate and to sense. This conclusion is said to be evident because there are three species of living things: the first is that which only vegetates, and is therefore intrinsically nourished, increased, and generated, and all plants belong here. The second is that which, besides vegetation, also exercises movement and sensation, and all irrational animals pertain to this. Finally, the third species is that which, besides vegetation, sensation, and locomotion, also reasons, and only the rational animal, namely man alone, is referred to this. It is confirmed: if in man, besides vegetation, sensation, and locomotion, reasoning also occurs, then these operations, or accidental life, recognize in him a certain principle, or root, or what is the same, a substantial life, and indeed in the same genus, for otherwise these

operations could not emanate from it. Therefore, the substantial life, or soul of man, will be rational. The reason for the second is: there are two first principles according to the second supposition of every permanent substantial whole, or "in fact," namely matter and form. But man is also a permanent substantial whole; therefore, he will also have as many primary principles. They subsume: but primary principles, or "that by which" a substantial whole consists, are the same according to suppositions 1 and 2 as the essential parts of the whole. Therefore, if the primary principles of man are two, his primary essential parts will also be only two, namely primary matter, as they already proved in the previous conclusion, and the rational soul. And again they subsume: but if the rational soul is that essential part from which man derives his essential predicate—namely, that he is a rational animal—then it follows that the rational soul is the most principal part of man. Therefore, it is established that the rational soul is the other essential part of the human body, and indeed the most principal. And this is that single root by virtue of which man is, and is called, the image of GOD. Hence it is 1. Ingenerable, namely created by God alone