That these three constituents differ very materially from those of a primitive being is evident: for, in a primitive being, _the term_ is a pure potency that receives its first actuation; whilst in the compound nature it consists of a number of actual beings which are no longer potential respecting their first actuation, but only with regard to their composition, which gives them a second and relative actuation in the compound. Again, _the act_, in the primitive being, is a product of creation, calculated to give the first existence to its term; whilst in the compound nature it is the product of actions interchanged between the components, and gives them, not to exist, but to be united so as to form a new specific essence. Lastly, _the complement_, in a primitive being, is the existence of a thing absolutely _one_, whilst in the compound nature it is the existence of a thing whose oneness is altogether relative. In all compounds of this kind—viz., whose form is their composition—the components are, of course, physical beings, as we have stated; but their composition is only a metaphysical entity. Indeed, we are wont to call it “physical composition”; but we do not mean that it is a physical being; we only mean that it is the composition “of physical beings.” We know that formal composition is that by which the components are formally bound with one another; and we know also that the components are thus bound in consequence of their mutual actions, and that such actions cannot be conceived to be complete in nature, except inasmuch as they are received in their proper subjects—viz., in the components themselves. And therefore the composition which is styled “physical” is, of its own nature, only an incomplete and metaphysical entity; and, in a like manner, the actuality of the physical compound is not a physical being, as it cannot be found outside of that of which it is the result. But a compound of the kind just mentioned is sometimes intended for an end which cannot be attained without the concurrence of a higher principle. Then, by the introduction of this new principle, a second kind of substantial compound arises, in which one of the components (the higher principle) ranks as the formal, and the others as the material, constituent of the compound nature. Such is the case with our own bodies; which, to fulfil the ends for which they are organized by nature, besides their bodily constitution and organism, require the infusion of a distinct principle of life. Hence the _formal_ constituent of man, and of all animals too, is the principle of life, or the soul; whilst his _material_ constituent is the body, with its organic constitution.