Summa contra Gentiles2.31 Chapter XXXI. That it is not necessary for creatures to have been always

It remains for us to prove from the foregoing that it is not necessary for created things to have been from eternity.

Because if it be necessary for the universe of creatures, or any particular creature whatsoever, to be, it must have this necessity either of itself or from another. But it cannot have it of itself. For it was proved above' that every being must be from the first being. Now that which has being, not from itself, cannot possibly have necessity of being from itself: since what must necessarily be, cannot possibly not be; and consequently that which of itself has necessary being, has of itself the impossibility of not being; and therefore it follows that it is not a non-being; wherefore it is a being.

If, however, this necessity of a creature is from something else, it must be from a cause that is extrinsic; because whatever we may take that is within the creature, has being from another. Now an extrinsic cause is either efficient or final. From the efficient cause, however, it follows that the effect is necessarily, when it is necessary for the agent to act: for it is through the agent's action that the effect depends on the efficient cause. Accordingly if it is not necessary for the agent to act in order that the effect be produced, neither is it absolutely necessary for the effect to be. Now God does not act of necessity in producing creatures, as we have proved above. Wherefore it is not absolutely necessary for the creature to be, as regards necessity dependent on the efficient cause. Likewise neither is it necessary as regards the necessity that depends on the final cause. For things directed to an end do not derive necessity from the end, except in so far as without them the end either cannot be,—as preservation of life without food,—or cannot be so well,—as a journey without a horse. Now the end of God's will, from which things came into being, can be nothing else but His goodness, as we proved in the First Book. And this does not depend on creatures, neither as to its being,—since it is fer se necessary being,—nor as to well-being,—since it is by itself good simply; all of which were proved above. Therefore it is not absolutely necessary for the creature to be: and consequently neither is it necessary to suppose that the creature has been always.

Again. That which proceeds from a will is not absolutely necessary, except perhaps when it is necessary for the will to will it. Now God, as proved above, brought things into being, not by a necessity of His nature, but by His will: nor does He necessarily will creatures to be, as we proved in the First Book. Therefore it is not absolutely necessary for the creature to be: and therefore neither is it necessary that it should have been always.

Moreover. It has been proved above that God does not act by an action that is outside Him, as though it went out from Him and terminated in a creature, like heating which goes out from fire and terminates in wood. But His will is His action; and things are in the way in which God wills them to be. Now it is not necessary that God will the creature always to have been; since neither is it necessary that God will a thing to be at all, as we proved in the First Book. Therefore it is not necessary that creatures should have been always.

Again. A thing does not proceed necessarily from a voluntary agent except by reason of something due. But God does not produce the creature by reason of any debt, if we consider the production of all creatures absolutely, as we have shown above. Therefore God does not necessarily produce the creature. Neither therefore is it necessary, because God is eternal, that He should have produced the creature from eternity.

Further. It has been proved that absolute necessity in created things results, not from a relation to a principle that is of itself necessary to be, namely God, but from a relation to other causes which are not of themselves necessary to be. Now the necessity resulting from a relation which is not of itself necessary to be, does not necessitate that something should have been always: for if something runs it follows that it is in motion, but it is not necessary for it to have been always in motion, because the running itself is not necessary. Therefore nothing necessitates that creatures should always have been.