We’ve finally reached the promised discussion about infinity, or rather infinite power being required to create something out of nothing. This and next week wraps up the arguing proving only God can create.
 HENCE it is evident that no body can produce anything by creation.
 For no body acts unless it be moved: since agent and patient must be together, as also maker and that which is made: and those things are together which are in the same place, as stated in 6 Phys., and a body does not acquire a place except by movement. But no body is moved except in time. Wherefore whatever is done by the action of a body is done successively: whereas creation, as we have proved, is without succession. Therefore nothing can be produced by way of creation by any body whatever.
 Further. Every agent that acts through being moved, of necessity moves that on which it acts, for the thing made and the thing patient are consequent upon the disposition of maker and agent, since every agent produces its like. Hence, if the agent, while varying in disposition, acts in as much as it is changed by movement, it follows that also in the patient and the thing made there is a succession of dispositions, which is impossible without movement. Now no body moves unless it be moved, as we have proved. Therefore nothing results from the action of a body, except by the movement or change of the thing made. But creation is neither change nor movement, as proved above. Therefore no body can cause a thing by creating it.
Notes Don’t forget that by “movement” it is meant “change”. A thing can stay in place and be changed. Something must cause that change, something actual must actualize the potential. This is echoed in the next argument.
 Again. Since agent and effect must needs be like each other, a thing cannot produce the whole substance of the effect, unless it act by its entire substance; thus the Philosopher proves conversely (7 Metaph.), that if a form without matter acts by its whole self, it cannot be the proximate cause of generation wherein the form alone is brought into act. Now no body acts by its whole substance, although the whole of it acts: for since every agent acts by the form whereby it is actual, that alone is able to act by its whole substance, the whole of whose substance is a form: and this can be said of no body, because every body has matter, since every body is changeable. Therefore no body can produce a thing as to the whole substance of that thing, and this is essential to creation.
 Further. To create belongs exclusively to an infinite power. For an agent’s power is so much the greater, according as it is able to bring into act a potentiality more distant from act: for instance that which can produce fire from water in comparison with that which can produce it from air. Hence where pre-existing potentiality is altogether removed, all proportion to a determinate distance is surpassed; and thus the power of an agent that produces something without any pre-existing potentiality, must surpass all conceivable proportion to the power of an agent that produces something out of matter. But no power of a body is infinite, as the Philosopher proves in 8 Phys. Therefore no body can create a thing, for this is to make something out of nothing.
Notes Here’s the key: “pre-existing potentiality is altogether removed.” Pre-existing potentiality is something not nothing. Potentials exist in a sense. Failing to understand this is what causes some physicists to speculate that creation happens in the absence of God via (say) fields or quantum uncertainties. But the latter, at least, are potentials. They are not nothing. The rest of the argument follows. Infinite power is required to bring material+energy existence into being. And to sustain it in being, since all change “bottoms out” at God, as was proved in the first Book.
 Moreover. Mover and moved, maker and made must be together, as proved in 7 Phys. Now a bodily agent cannot be present to its effect except by contact, whereby the extremes of contiguous things come together. Wherefore it is impossible for a body to act save by contact. But contact is of one thing in relation to another. Hence where there is nothing pre-existent besides the agent, as happens in creation, there can be no contact. Therefore no body can act by creating.
Notes “Contact”, of course, includes that by fields, i.e. the interaction of fields (or whatever might replace this concept, as unlikely as it now seems).
 Thus we may see the falseness of the position of those who say that the substance of the heavenly bodies causes the matter of the elements, since matter can have no cause except that which acts by creating: because matter is the first subject of movement and change.