Summa contra Gentiles2.42 Chapter XLII. That the first cause of the distinction of things is not the order of secondary agents

We may also prove from the same premisses that the distinction of things is not caused by the order of secondary agents; as those maintained who held that God, since He is one and simple, produces but one effect, which is the first created substance: and that this, because it cannot equal the simplicity of the first cause,—not being pure act, but having a certain admixture of potentiality—has a certain multiplicity, so that it is able to produce some kind of plurality; and that in this way, effects ever failing of the simplicity of their causes, the multiplication of effects results in the diversity of the things whereof the universe consists.

Accordingly this opinion does not assign one cause to the entire diversity of things, but a different cause to each particular effect: and the entire diversity of things it ascribes to the concurrence of all causes. Now' we say that those things happen by chance, which result from the concurrence of various causes, and not from one determinate cause. Wherefore the distinction of things and the order of the universe would be the result of chance.

Moreover. That which is best in things caused is reduced, as to its first cause, to that which is best in causes: for effects must be proportionate to their causes. Now the Marcion? * Cf. end of ch. By the foregoing..

best among all things caused is the order of the universe, wherein the good of the universe consists, even as in human affairs the good of the nation is more God-like than the good of the individual Hence we must reduce the order of the universe to God as its proper cause. Whom we have proved above to be the sovereign good. Therefore the distinction of things, wherein consists the order of the universe, is the result not of secondary causes, but rather simplicity of the first cause.

Further. It seems absurd to assign a defect in things as cause of that which is best in things. Now the best in things caused is their distinction and order, as shown above. Therefore it is unreasonable to assert that this distinction is the result of secondary causes failing of the simplicity of the first cause.

Again. In all ordered active causes, where action is directed to an end, the ends of the secondary causes must be directed to the end of the first cause: thus the ends of the arts of war, horsemanship, and bridle-making are directed to the end of the political art. Now the origin of beings from the first being is by an action directed to an end: since it is according to intellect, as we have proved and every intellect acts for an end. If, therefore, in the production of things there are any secondary causes, it follows that their ends and actions are directed to the end of the first cause, and this is the last end in things caused. And this is the distinction and order of the parts of the universe, which order is the ultimate form, so to speak. Therefore the distinction and order in things is not on account of the actions of secondary causes; but rather the actions of secondary causes are on account of the order and distinction to be established in things.

Further. If the distinction of the parts of the universe and their order is the proper effect of the first cause, through being the ultimate form and the greatest good in the universe, it follows that the distinction and order of things must be in the intellect of the first cause: because in things that are made by an intellect, the form produced in the things made proceeds from a like form in the intellect: for instance, the house which exists in matter proceeds from the house which is in an intellect. Now the form of distinction and order cannot be in an active intellect, unless the forms of the things which are distinct and ordered be therein. Wherefore in the divine intellect there are the forms of various things distinct and ordered, nor is this incompatible with His simplicity, as we have proved above. Accordingly, if things that are outside the mind proceed from forms that are in the intellect, it will be possible, in things that are effected by an intellect, for many and diverse things to be caused immediately by the first cause, notwithstanding the divine simplicity, on account of which some fell into the aforesaid opinion.

Again. The action of one who acts by intellect terminates in the form which he understands, and not in another, except accidentally and by chance. Now God is an agent by His intellect, as we have proved: nor can His action be affected by chance, since He cannot fail of His action. It follows, therefore, that He produces His effect for the very reason that he understands and intends that same effect. But by the same idea that He understands one effect. He can understand many effects other than Himself. Wherefore He can at once cause many things without any intermediary.

Moreover. As we have shown above, the power of God is not confined to one effect, and this is befitting His simplicity: because the more a power is united, the nearer it approaches to infinity, being able to extend to so many more things. But it does not follow that one thing only can be made by one, except when the agent is determined to one effect. Wherefore, we are not bound to conclude that, because God is one and utterly simple, therefore many things cannot proceed from Him, except by means of certain things that fail of His simplicity.

Further. It was shown above that God alone can create. Now there are many things which cannot come into being except by creation: such as all those which are not composed of form and matter subject to contrariety; because the like must needs be incapable of being generated, since all generation is from a contrary and from matter. Such are all intellectual substances, and all heavenly bodies, and even primary matter itself. We must therefore assert that all such things have taken the origin of their being from God immediately.

Hence it is said (Gen. i. i): In the beginning God created heaven and earth: and (Job xxxvii. 18): Thou perhaps hast made the heavens with Him, which are most strong as if they were of molten brass.

By the foregoing we exclude the opinion of Avicenna, who says that God, by understanding Himself, produced one first intelligence, in which there is already potentiality and act; that this, through understanding God, produces the second intelligence; through understanding itself as being in act, produces the soul of the sphere; and through understanding itself as being in potentiality, produces the substance of the first sphere. And thus starting from this point he explains the causing of the diversity of things by secondary causes.

We also exclude the opinion of certain early heretics who said that not God but the angels created the world: of which error Simon Magus is said to have been the original author.