One objection to the possibility of divine action in the natural world comes from the conservation of energy. The objection is applied both to the special action of God in the world (see Plantinga’s extensive discussion in Where the Conflict Really Lies) and even more generally to any action of God on the world (see David Papineau’s claim that the discovery of the principle was a watershed moment in Naturalism).
I don’t see any way out of Plantinga criticism that the principle assumes a closed system, which is itself a criticism already given in the Thomist manuals (see, for example, E. Filion, who considers the Plantinga’s argument only worthy of fourth place in his series of refutations.) That said, it’s much more paradoxical to notice that that because the conservation of energy is a way of saying that motion and change can never come to be or pass away, it is equivalent to Aristotle’s first principle in a proof that God must act on the universe.
From Physics VIII.6:
The following argument also makes it evident that the first mover must be something that is one and eternal. We have shown that there must always be motion. That being so, motion must also be continuous, because what is always is continuous, whereas what is merely in succession is not continuous. But further, if motion is continuous, it is one: and it is one only if the first mover and the moved that constitute it are each of them one, since in the event of a thing’s being moved now by one thing and now by another the whole motion will not be continuous but successive.
The order of argument seems to be this:
1.) Motion necessarily is
Energy is essentially a source of motion, and it is impossible for energy to come to be or pass away, therefore, etc.
(for a fuller account of how even potential energy depends on some actual motion, see the next post.)
2.) Therefore, motion is continuous.
If it is not continuous, some hiatus is introduced into the series. But if some hiatus is introduced, energy ceases to be into this hiatus and comes to be on the far side of the hiatus.
3.) if continuous, therefore one.
Whatever is undivided is one in being.
4.) A motion is one necessarily with respect to its mover.
If two men are moving, is it one motion or two? If they’re in a charging army, it’s one; if they are two randomly chosen pedestrians, it is two. What counts as one motion therefore needs some reference to the agent cause.
5.) Therefore, there is some one mover that is necessarily one and eternal.
Now at first glance it might look like this is exactly what energy is. But if this is the case, then no two previously distinct lines of energetic activity could merge; and energy could never be used as an instrument, since all instruments are essentially moved movers. But this is not so.
6.) Therefore, behind energy, there is some mover and agent, necessarily one and eternal.