Does everything in time change?

Over the last two days, I’ve been thinking critically about Aquinas’ First Way. Central to my thinking, and especially yesterday’s post, was the idea that you could have an unmoved mover who is in time but isn’t pure act and who isn’t God. Such an unmoved mover constantly and unchangingly exercises—perhaps mentally—one and the same causal power to make something else move.

But I now wonder if this is possible. Suppose a demiurge that exists in time and has the power to make Bob rotate, and constantly exercises this power. Could this demiurge be unchanging? After all, at noon the demiurge is actively rotating Bob at noon, and at 1 pm the demiurge is actively rotating Bob at 1 pm. We can easily and coherently suppose that the demiurge engages in qualitatively the same activity at 1 pm as at noon. That was the intuition that was driving my thinking about this. But can we coherently add that it is the numerically same activity? For if it’s not numerically the same activity at 1 pm as at noon, then the demiurge has undergone a change, from engaging in activity a₁₂ to engaging in activity a₁₃, even if the two activities are exactly alike.

I am not sure, but I feel a pull to thinking that rotating Bob at 1 pm is a different thing from rotating Bob at noon, assuming that the agent is in time. I don’t just mean that it has different effects—which it does, since spinning-at-noon is a different effect from spinning-at-one—but that the activity of causing rotation is itself different. Maybe the pull comes from this thought. Perdurantists think that substances exist at different times by having different temporal parts at them. Perdurantism is likely false for substances. But whether or not it is true for substanes, it seems very plausible for events and activities. What made World War II exist on each day between September 1, 1939 and September 2, 1945 is that there were hostilities on each day, hostilities that are a part of World War II. Even if on two successive days the hostilities happened to be exactly alike, they would have been numerically different hostilities. If this is right in general, then the activity of rotating Bob at 1 pm is numerically different from that of rotating Bob at noon.

Furthermore, I think existence is a kind of activity. This is most obvious in the case of living things, given the Aristotelian idea that life is the existence of the living and life is an activity, but I think is true in general. Thus a thing that exists in time over a lifetime engages in a sequence of numerically different activities—existing at t₁, existing at t₂, and so on. And hence it changes. And intrinsically so. If so, then everything that exists in time must always change.

If the suggestion that there are no unchanging activities that last over time, then we can escape my worry yesterday that perhaps the sequence of moved movers in the First Way leads to a mover that is unchanging with respect to the activity of moving the next mover in the sequence but is still changing in some other coincidental respect. For the activity of moving the next mover in the sequence would have to change over time, and so the mover would be changing in respect of of its moving the next item in the sequence.

But perhaps not. For we might admit that in all the cases we are familiar with, activity only perdures over time, and there is always something numerically different happening at different times, but say that we could still imagine a being where the numerically same activity is temporally multilocated. And such a being could everlastingly rotate Bob with the activity of spinning Bob being genuinely unchanging.

I don’t know.

How do we get to an unmoved mover?

I just realized that there is a difficulty in Aquinas’ First Way that I think hasn’t been noted, which builds on the difficulty noted yesterday.

Put the First Way in the following simpleminded way, which I think captures the central ideas:

1. Causes of change are either passers-on of change or originators of change.

2. It can’t be that the causes of change are all passers-on of change.

3. So there must be an originator of change.

4. And this is an unmoved mover (or, more precisely, unchanged changer).

There is a fair amount of detail one can fill in to argue for (2), but that’s not what I want to focus on. I want to focus on the move from (3) to (4).

What licenses us in thinking that an originator of change is itself unchanging?

The idea seems to be that if a cause of change is itself changing, then it is merely a passer-on of change. But this need not be. In my previous post, I imagined an unchanging and timeless demiurge endowed by God with the power to originate change, and noted that in that scenario the demiurge is an unmoved mover but isn’t God.

But now let’s build up and modify my demiurge story. First, let’s be concrete about what motion the demiurge causes. The demiurge has been gifted by God with the power to directly will Bob to rotate around a fixed axis, and the demiurge changelessly exercises this power. (Maybe Bob is one of the Aristotelian heavenly spheres). Second, let’s specify that the demiurge, albeit unchanging, is in time and has an unchanging body in addition to a mind and will. If we can’t have a changeless thing in space and time, don’t worry about it. The third step will fix that. The third step is this. The demiurge itself is caused by God to slowly orbit the sun in a way that the demiurge does not notice.

Thus, we have a demiurge with a mental power to make Bob rotate, and the demiurge exercises this mental power changelessly. At the same time, and completelessly coincidentally to the demiurge’s exercise of the mental power to make Bob rotate, the demiurge orbits the sun.

The demiurge is thus a moved mover. But it is also an originator rather than passer-on of change. In Aristotelian terminology, the demiurge is a moved mover per accidens: its own movement around the sun is coincidental to its origination of Bob’s axial rotation.

We cannot, thus, assume from the existence of an originator of change that there is an unmoved mover.

Does Aquinas have the resources to fill in the gap? Of course, if the (accidentally) moved originator of change coming out of step (3) of the argument is itself changing, that change has to have a cause, and we can then run the argument again. If we can rule out an ungrounded infinite sequence of accidentally moved originators of change—ones that like our demiurge happen to be moving in one respect but produce change by a coincidental exercise of power—then we can get to a genuinely unmoved mover.

But Aquinas’ main tool for avoiding regresses in cosmological arguments is the idea that there cannot be an infinite regress in a per se causal sequence. And while there are complications in the notion of a per se causal sequence, I think it is pretty clear that the sequence I am imagining is not a per se causal sequence. The demiurge’s moving of Bob is coincidental to the demiurge’s own motion. Suppose that a demiurge makes Bob spin by an unchanging exercise of a mental power, and a tetartourge by an unchanging exercise of a mental power makes the demiurge coincidentally slowly orbit the sun while the tetartourge coincidentally orbits the moon. Then the tetartourge is not a cause of Bob’s motion. But in a per se causal sequence we have transitivity: the earlier items are always causes of the later ones. So this is not a per se causal sequence.

Of course, we might ask what explains the demiurge’s (and tetartourge’s) possession and exercise of the mental power to make something else move. But now we are deviating from the First Way: we are asking for explanations of something other than change. I think one can fill this in, by an argument about causation and regresses rather than change and motion. But if we do that, then the stuff about change and motion that is at the heart of the First Way can simply drop out.

I titled my previous post “An easily patched hole in the First Way”. But I think I was too glib there, too. In that context, too, I think one needs to go beyond the resources of the First Way to patch the hole.

An easily patched hole in the First Way

In his First Way, Aquinas argues that as we trace back the sequence of movers from effect to cause, we get to a first unmoved mover, and this is God.

But need the unmoved mover thus reached in the sequence of movers be God? Imagine this scenario. God creates some material beings, as well as an unchanging, timeless and immaterial demiurge that has the power to make the material beings move—and indeed exercises that power. Then if we were to trace back the sequence of movers, the unmoved mover we would get to would be the demiurge, not God. This demiurge would have potentiality, but not a temporal potentiality, so it would not be itself in motion, and hence it would be an unmoved mover.

This doesn’t deeply affect the argument, since Aquinas could do the same thing as he does in the Third Way, where he traces contingent beings to a necessary being, and then considers the possibility of necessary beings that get their necessity from other beings, and traces it back to an absolutely necessary being, namely God. Similarly, God could say that any unmoved mover that has some potentiality or contingency depends on a prior being and so on, and in the end we would get to God anyway.

Indeed, even in this scenario with a demiurge, we might want to say that it is God and not the demiurge who is the first unmoved mover. For God would still be a mover, albeit working through the demiurge who is a secondary cause, and God would be unmoved, and God would be first. So Aquinas would still be correct that the “first mover” is God—it’s just that the scenario suggests that Aquinas does skip a step.