That the body is a physical being and a substance there is no doubt; and that the soul also is a physical being and a substance distinct from the body is conclusively shown in all good treatises of anthropology. The soul and the body are therefore two physical components, and make up a physical compound. The animal life, however, which is the result of the animation of the body by the soul—and is, therefore, the _complement_ of the compound—is not a third physical component, but a metaphysical entity; and thus of the three principles which constitute the animal, the first and the second only are to be reckoned as physical parts. And now, since we have stated that the constituents of compound natures may have either a physical or only a metaphysical entity, we must further inform our readers that a great number of authors are wont to consider all the real constituents of physical beings as so many _physical_ entities. But we would say that in this they are mistaken; for although it is evidently true that the constituent principles of a physical being have a physical existence in the being to which they belong, it cannot be inferred that therefore all such principles must be called _physical_ beings; as some of them can neither have an independent existence nor be even conceived without referring to their correlative principles. Thus the act and the term of a primitive being are both entitatively less than physical beings; for the first being we find in the physical order is that which arises out of them. It is not, therefore, the same thing to say that a being is physically real, and to say that it is made up of physical realities. The first assertion may be true, and the second false; because a thing which is _one_ has only _one_ existence, and nevertheless implies three principles; whence it appears that it is impossible to conceive each of the three principles as having a _distinct_ existence. And since that which has no distinct existence in nature is not a physical being, accordingly the principles of primitive physical beings are not physical, but only metaphysical, realities.