Objection 1. It would seem that it does not belong to God alone to create, because, according to the Philosopher (De Anima ii, text 34), what is perfect can make its own likeness. But immaterial creatures are more perfect than material creatures, which nevertheless can make their own likeness, for fire generates fire, and man begets man. Therefore an immaterial substance can make a substance like to itself. But immaterial substance can be made only by creation, since it has no matter from which to be made. Therefore a creature can create.
Objection 2. Further, the greater the resistance is on the part of the thing made, so much the greater power is required in the maker. But a "contrary" resists more than "nothing." Therefore it requires more power to make (something) from its contrary, which nevertheless a creature can do, than to make a thing from nothing. Much more therefore can a creature do this.
Objection 3. Further, the power of the maker is considered according to the measure of what is made. But created being is finite, as we proved above when treating of the infinity of God (7, 2,3,4). Therefore only a finite power is needed to produce a creature by creation. But to have a finite power is not contrary to the nature of a creature. Therefore it is not impossible for a creature to create.
On the contrary, Augustine says (De Trin. iii, 8) that neither good nor bad angels can create anything. Much less therefore can any other creatures.
I answer that, It sufficiently appears at the first glance, according to what precedes (1), that to create can be the action of God alone. For the more universal effects must be reduced to the more universal and prior causes. Now among all effects the most universal is being itself: and hence it must be the proper effect of the first and most universal cause, and that is God. Hence also it is said (De Causis prop., iii) that "neither intelligence nor the soul gives us being, except inasmuch as it works by divine operation." Now to produce being absolutely, not as this or that being, belongs to creation. Hence it is manifest that creation is the proper act of God alone.
It happens, however, that something participates the proper action of another, not by its own power, but instrumentally, inasmuch as it acts by the power of another; as air can heat and ignite by the power of fire. And so some have supposed that although creation is the proper act of the universal cause, still some inferior cause acting by the power of the first cause, can create. And thus Avicenna asserted that the first separate substance created by God created another after itself, and the substance of the world and its soul; and that the substance of the world creates the matter of inferior bodies. And in the same manner the Master says (Sent. iv, D, 5) that God can communicate to a creature the power of creating, so that the latter can create ministerially, not by its own power.
But such a thing cannot be, because the secondary instrumental cause does not participate the action of the superior cause, except inasmuch as by something proper to itself it acts dispositively to the effect of the principal agent. If therefore it effects nothing, according to what is proper to itself, it is used to no purpose; nor would there be any need of certain instruments for certain actions. Thus we see that a saw, in cutting wood, which it does by the property of its own form, produces the form of a bench, which is the proper effect of the principal agent. Now the proper effect of God creating is what is presupposed to all other effects, and that is absolute being. Hence nothing else can act dispositively and instrumentally to this effect, since creation is not from anything presupposed, which can be disposed by the action of the instrumental agent. So therefore it is impossible for any creature to create, either by its own power or instrumentally--that is, ministerially.
And above all it is absurd to suppose that a body can create, for no body acts except by touching or moving; and thus it requires in its action some pre-existing thing, which can be touched or moved, which is contrary to the very idea of creation.
Reply to Objection 1. A perfect thing participating any nature, makes a likeness to itself, not by absolutely producing that nature, but by applying it to something else. For an individual man cannot be the cause of human nature absolutely, because he would then be the cause of himself; but he is the cause of human nature being in the man begotten; and thus he presupposes in his action a determinate matter whereby he is an individual man. But as an individual man participates human nature, so every created being participates, so to speak, the nature of being; for God alone is His own being, as we have said above (7, 1,2). Therefore no created being can produce a being absolutely, except forasmuch as it causes "being" in "this": and so it is necessary to presuppose that whereby a thing is this thing, before the action whereby it makes its own likeness. But in an immaterial substance it is not possible to presuppose anything whereby it is this thing; because it is what it is by its form, whereby it has being, since it is a subsisting form. Therefore an immaterial substance cannot produce another immaterial substance like to itself as regards its being, but only as regards some added perfection; as we may say that a superior angel illuminates an inferior, as Dionysius says (Coel. Hier. iv, x). In this way even in heaven there is paternity, as the Apostle says (Ephesians 3:15): "From whom all paternity in heaven and on earth is named." From which evidently appears that no created being can cause anything, unless something is presupposed; which is against the very idea of creation.
Reply to Objection 2. A thing is made from its contrary indirectly (Phys. i, text 43), but directly from the subject which is in potentiality. And so the contrary resists the agent, inasmuch as it impedes the potentiality from the act which the agent intends to induce, as fire intends to reduce the matter of water to an act like to itself, but is impeded by the form and contrary dispositions, whereby the potentiality (of the water) is restrained from being reduced to act; and the more the potentiality is restrained, the more power is required in the agent to reduce the matter to act. Hence a much greater power is required in the agent when no potentiality pre-exists. Thus therefore it appears that it is an act of much greater power to make a thing from nothing, than from its contrary.
Reply to Objection 3. The power of the maker is reckoned not only from the substance of the thing made, but also from the mode of its being made; for a greater heat heats not only more, but quicker. Therefore although to create a finite effect does not show an infinite power, yet to create it from nothing does show an infinite power: which appears from what has been said (ad 2). For if a greater power is required in the agent in proportion to the distance of the potentiality from the act, it follows that the power of that which produces something from no presupposed potentiality is infinite, because there is no proportion between "no potentiality" and the potentiality presupposed by the power of a natural agent, as there is no proportion between "not being" and "being." And because no creature has simply an infinite power, any more than it has an infinite being, as was proved above (Question 7, Article 2), it follows that no creature can create.
Source: Summa Theologica (New Advent)