Introduction to the Philosophy and Writings of Plato

...according to nourishing, increasing, and generating things similar to itself. Nature, however, is inseparable from a physical subject and is indigent Lacking or dependent; not self-sufficient., so it cannot be the ultimate principle, since it depends on that which is subordinate to it. For it would not be strange if, as a secondary principle, it depended on a higher principle above it; but it would be very strange if it were dependent on things that come after it, and for which it is supposed to be the source.

By these same arguments, we can show that the first principle cannot be the irrational soul, whether it is the part that feels (sensitive) or the part that desires (orectic From the Greek 'orektikos,' referring to the faculty of appetite, desire, or impulse.). Even if it appears to have some degree of separation because of its power to move and its gnostic energies Powers related to knowing or perceiving., it is nevertheless bound to the body and has something inseparable from it. It is unable to convert itself to itself A Neoplatonic term for self-reflexivity or self-awareness; the ability of a consciousness to look inward at its own nature rather than being focused only on external objects.; instead, its energy is mixed with the physical subject. It is evident that its essence is of this kind; for if it were liberated and free within itself, it would display an independent energy and would not always be directed toward the body. Sometimes it would turn toward itself, or even if it remained directed toward the body, it would at least judge and examine its own nature.

The activities of the mass of mankind, though they are preoccupied with external things, still demonstrate that there is something "separate" within them. This is because they consult with themselves about how to act and realize that deliberation is necessary to achieve a perceived good or avoid an evil. In contrast, the impulses of other animals are uniform and spontaneous; they move in sync with their physical organs and require only their senses to seek pleasure and avoid pain from external objects. If the body shares in pleasure and pain and is affected by them, it is clear that these psychical energies Activities belonging to the soul (psyche). are exerted in a way that is mingled with the body. They are not purely "of the soul," but are also corporeal. Perception belongs to the animated body—or to the "soul made physical"—though in such perception the character of the soul still holds sway over the physical. Just as in physical bodies, the physical character dominates in terms of spatial extension and existence. Because the irrational soul has its being in something different from itself, it is dependent on that subordinate thing; therefore, such a thing cannot be the ultimate principle.

Prior to this essence, however, we see a certain form that is separate from a physical subject and is "converted to itself"—this is the rational nature. Our soul presides over its own energies and corrects itself. This would not be possible unless it could turn inward upon itself; and it could not turn inward unless it had an essence separate from the body. Thus, it is not dependent on what is subordinate to it.

Shall we then say that the rational soul is the most perfect principle? No, because it does not exert all its powers at once, but is always lacking the greater part of them. The ultimate principle must want for nothing; but the rational nature is an essence that is in want of its own activities.

Some might argue that the soul is an eternal essence with never-failing powers that always match its essence—being "self-moved" and "ever-living"—and is therefore not "indigent." However, the first principle must be perfectly self-sufficient. A soul that undergoes change in its activities cannot be the most proper principle.

Therefore, it is necessary that there be something prior to this, which is in every respect immutable in its nature, life, and knowledge, and in all its powers. This is what we call an eternal and immutable essence: the highly honored Intellect. Aristotle, having ascended to this level, believed he had discovered the first principle. For what could be missing from that which perfectly contains within itself its own "fullnesses" or pleromata From the Greek 'pleroma,' meaning a state of fullness or the sum total of spiritual powers., and which is not changed by anything being added or taken away?

Yet, is this Intellect not also "one and many," a "whole and parts," containing within itself things that are first, middle, and last? The lower parts of this fullness stand in need of the higher, and the higher need the lower, and the whole needs its parts. Things that are related are dependent on each other. Even the "one" here is dependent on the "many," because it exists within the many. Or it could be said that this "one" collects the "many," but not by itself—only in conjunction with them.

Therefore, even in this principle, there is much that is dependent. Since the Intellect generates its own "fullnesses" within itself to complete the whole, it is dependent on itself—not only is the generated part dependent on the generator, but the generator depends on the generated to achieve the completion of the whole. Furthermore, the Intellect both understands and is understood; it is both the thinker and the object of thought. Thus, the "thinker" (the intellectual) is dependent on the "object" (the intelligible) as the thing it desires to know; and the object is in want of the thinker because it wishes to be...