Summa contra Gentiles3.22 Chapter XXII. How things are directed in various ways to their respective ends

It may be shown from the foregoing that the last means whereby a thing is directed to its end is its operation;

in various ways, however, according to the variety of opera- 4Ch, xx. 2 (Ch. xx:

tions. For some things have an operation whereby they move something else; such are heating, and cutting: and some have an operation in being moved by another: such are being heated, and being cut. Some operations are a perfection of an actually existing operator, and do not tend to the transmutation of something else: in the former respect these differ from passion and movement, and in the latter from an action which effects a transmutation on some external matter: as an instance of such an operation we have understanding, sensation, will. Wherefore it is clear that things which are set to move or operate only, without moving or making any thing themselves, tend to the divine likeness in that they are perfect in themselves; while those which make and move, as such, tend to a divine likeness, in that they are causes of other things; and that those which move through being moved tend to the divine likeness in both ways.

The lower bodies, in so far as they are moved with natural movements, are considered to be moved only, and not to move except accidentally: for if a stone in its descent puts into motion something that stood in its path, it is an accident: and the same applies to alteration and other movements.

a divine likeness in the point of their being perfect in themselves, as having their proper form and their proper place. The heavenly bodies, however, move because they are moved: so that the end of their movement is to attain toa divine likeness in both respects. As regards their own perfection, inasmuch as a heavenly body may be actually where previously it was potentially—Nor does it for this reason attain less to its perfection, although it retains its potentiality matter tend to its perfection by acquiring actually the form which it had potentially before, although it ceases to have the one which it had before actually: for thus matter receives successively all the forms to which it has a potentiality, so that its whole potentiality is actualized successively;

a heavenly body is in potentiality to a particular whereabouts, even as primary matter is to a particular form, it attains to its perfection by the fact that its entire potentiality to a particular whereabouts is successively actualized, which could not happen simultaneously.

Inasmuch as they move by moving, the end of their movement is the attainment of a divine likeness, in that they are causes of other things. Now they are the causes of other things, by causing generation and corruption and other movements in this lower world. Accordingly the movements of heavenly bodies, in so far as they are principles of movement, are directed to generation and corruption in the world beneath them. And it is not unreasonable that the movements of heavenly bodies conduce to the generation of these lower things, although these inferior bodies are of small account in comparison with the heavenly bodies, and yet the end should be of greater account than the means. For the generator’s action tends to the form of the generated: and yet that which is generated is not of greater worth than the generator, but, in univocal/agents, is of the same species withit. Because the generator intends as its ultimate end not the form of the generated (which form is the end of generation); but the likeness to the Divine Being in the perpetuation of the species, and the diffusion of His goodness, by bestowing its specific form on others, and being the cause of other things. Likewise the heavenly bodies, although of more account than the lower bodies, nevertheless intend by means of their movements the generation of the latter bodies, and to bring to actuality the forms of things generated; not indeed as though this were their ultimate end; but as a means whereby to attain to an ultimate end, the divine likeness, to wit, in that they are causes of other things.

We must take note, however, that a thing, according as it participates in a likeness to God’s goodness, which is the object of His will, so too has it a share in a similitude to God’s will, whereby things are brought into being and preserved. The higher beings, however, participate in a likeness to the divine goodness in a more simple and universal manner; but the lower beings, ina more particular and divided way. Wherefore between heavenly and lower bodies, we observe a likeness, not of equiparance, as in things belonging to the same species; but as that which is to be observed between the universal agent and a particular effect. Wherefore just as in this lower world the intention of the particular agent is confined to good of this or that species, so is the intention of the celestial body inclined to the common good of the corporeal substance, which by generation is preserved, multiplied, and increased.

But since, as already stated, everything moved, as such, tends, as towards a divine likeness, to be perfect in itself; and since a thing is perfect in so far as it becomes actual: it follows that the intention of every thing that is in potentiality is to tend to actuality by way of movement. Consequently the more an act is posterior and perfect, the more is the appetite of matter inclined thereto. Therefore the appetite whereby matter seeks a form, must tend towards the last and most perfect act to which matter can attain, as to the ultimate end of generation. Nowcertain grades are to be found in the acts of forms. For primary matter is in potentiality, first of all, to the elemental form. While under the elemental form, it is in potentiality to the form of a mixed body: wherefore elements are the matter of a mixed body. Considered as under the form of a mixed body, it is in potentiality to a vegetative soul: for the act of such a body is a soul. Again, the vegetative soul is in potentiality to the sensitive, and the sensitive to the intellective. This is proved by the process of generation: for in generation we have first the fetus living with a plant life, afterwards with animal life, and lastly with human life. After this no later or more noble form is to be found in things subject to generation and corruption. Therefore the last end of all generation is the human soul, and to this does matter tend asits ultimate form. Consequently the elements are for the sake of the mixed body, the mixed body for the sake of living things: and of these plants are for the sake of animals, and animals for the sake of man. Therefore man is the end of all generation. And whereas the same thing is the cause of generation and preservation of things, the order of the preservation of things is in keeping with the aforesaid order of their generation. Hence we find that mixed bodies are preserved by the qualities becoming to the elements: plants are nourished by mixed bodies; animals derive their nourishment from plants; and some that are more perfect and powerful from the imperfect and weak. Man employs all kinds of things for his own use: some for food, some for clothing. Hence by nature he was made naked, as being able to make himself clothes from other things; even as nature provided him with no becoming nourishment except milk, so that he might supply himself with food from a variety of things. Some he employs as a means of transit: for he is inferior to many animals in swiftness and sustaining power, as though other animals were furnished for his needs. And over and above he employs all things endowed with a sensitive life for the perfection of his intellectual knowledge. Wherefore of man is it said in Psalm viii. 8, the words being addressed to God: Thou hast subjected all things under his feet. And Aristotle says (1 Polit. xi., xii.) that man exercises a natural sovereignty over all animals.

If, therefore, the movement of the heaven is directed to generation; and all generation is directed to man as the last end of this genus: it is evident that the end of the heavenly movement is directed to man as its last end in the genus of things subject to generation and movement.

This is expressed (Deut. iv. 19) where it is said that God made the heavenly bodies for the service of all the nations.