Chapter 18 — That in God there is no composition

From the foregoing we are able to conclude that there is no composition in God.

For in every composite thing there must be act and potency, since several things cannot become one simply, unless there be something actual there and something else potential. For those things that are in act are not united except as an assemblage or group, which are not one simply. Also, in these the very parts that are gathered together are as a potency with respect to the union: for they are actually united after being potentially unitable. But in God there is no potency. (Ch. 16.) Therefore, in him there is no composition.

Again. Every composite comes after its components. Therefore, the first being, which is God, (Ch. 14.) has no component parts.

Further. Every composite is potentially dissoluble, so far as its composite nature is concerned, although in some there is something else incompatible with dissolution. Now that which is dissoluble is in potency to non-being. But this cannot be said of God, since he necessarily exists by his very essence. Therefore, there is no composition in him.

Moreover. Every composition requires a compounder, for if there is composition, it results from several things, and things that are several in themselves would not combine together unless they were united by a compounder. If, then, God were composite, he would have a compounder, for he could not compound himself, since no thing is its own cause, for it would precede itself, which is impossible. Now the compounder is the efficient cause of the composite. Therefore, God would have an efficient cause: and thus he would not be the first cause, which was proved above. (Ch. 13.)

Again. In any genus, the more simple a thing is, the more excellent it is. For example, in the genus of hot things is fire, which has no admixture of cold. Therefore, whatever is the most noble of all things must be the height of simplicity. Now that which obtains the summit of nobility in things is what we call God, since he is the first cause, because the cause is more excellent than its effect. Therefore, there can be no composition in him.

Furthermore. In every composite thing the good does not belong to this or that part, but to the whole (and I speak of good in reference to that goodness which is proper to, and is the perfection of, the whole). Thus the parts are imperfect in relation to the whole: for example, the parts of a man are not a man, nor do the parts of the number six have the perfection of six, nor do the parts of a line come to the perfection of the measure found in the whole line. Therefore, if God is composite, his proper perfection and goodness are found in the whole of God but not in any of his parts. And thus the good that is proper to him will not be purely in him; and consequently he will not be the first and supreme good.

Further. Before every multitude it is necessary to find unity. Now in every composite there is multitude. Therefore, that which is before all things, namely God, must be devoid of all composition.