Monday, November 1, 2021

Divine conservation, existential inertia, presentism and simultaneous causation

As a four-dimensionalist, I have been puzzled both by the arguments that divine conservation is necessary secure the persistence of substances and the idea of existential inertia as a metaphysical principle.

Temporal extent seems little different metaphysically to me from spatial thickness, the “problem of persistence” seems to me to be a pseudo-problem, and both solutions to this pseudo-problem seem to me to be confused.

On the existential inertia side, a metaphysical principle that objects continue to exist unless their existence is interrupted by some other cause seems as ridiculous to me as a principle that objects are maximally thick (and long and deep) unless and until their thickness (or length or depth) is stopped by other causes. And divine action is needed to secure persistence only to the extent that it is needed to secure thickness (and length or depth). That said, I do think divine action is needed to secure thickness, as well as all other accidents of a thing, because substances are in some sense causes of their accidents, but all creaturely causation requires divine cooperation. But that, I think, is a slightly different line of argument from the arguments for persistence of substances (in particular, I don’t have a good argument for it that doesn’t already presuppose theism, while the arguments for conservation are supposed to provide reasons for accepting theism).

However, I now see how it is that presentism yields a real problem of persistence. Here’s the line of thought. First, note that contrary to the protestations of some presentists, it is very plausible that:

  1. Presentism implies that all causation is simultaneous.

For something that exists, at least at the time at which it is caused, cannot have as its cause something that doesn’t exist. But given presentism, only something present exists. So at a time at which E is caused, if the cause of E did not exist, we would have the exercise of a non-existent causal power, which is absurd.

But even if all causation is simultaneous, nonetheless:

  1. There is diachronic causal explanation.

Setting the alarm at night explains why it goes off in the morning, even if by the simultaneity thesis (1), setting the alarm cannot be the cause of the alarm going off. Diachronic causal explanation cannot simply be causation. So what is it? Here is the best presentist story I know (and it’s not original to me).

First, we can get some temporal extension by the following trick. Imagine a thing A persists over an interval of time from t1 to t2. At t2 is causes a thing B that persists over an interval of time from t2 to t3. The existence of A at t1 then causally explains the existence of B at t3. Note, however, that the existence of A at t1 does not cause the existence of B at t3. Causation happens at t2 (or perhaps over an interval of times—thus, A might persist until some time t2.5 < t3, and be causing B over all of the interval from t2 to t2.5), but not at any earlier time, since at earlier times A doesn’t exist. Thus, by supplementing the simultaneous causal relation between A and B at t2 with the persistence of A before t2 and/or the persistence of B after t2, we have, we can extend the relation into what one might call a fundamental instance of diachronic causal explanation.

Thus, a fundamental link in diachronic causal explanation consists of an instance of causation preceded and/or followed by an instance of persistence of the causing thing and/or the caused thing respectively. And a non-fundamental instance of diachronic causal explanation is a chain of fundamental links of diachronic causal explanations. (It may be that these diachronic causal explanations are very close to what Aquinas calls per accidens causal sequences.)

But for this to be genuine explanation, the persistence of the cause and/or effect needs to have an explanation. Divine conservation provides a very neat explanation: God necessarily exists eternally, and is simultaneous with everything (there may be some complications, though, with a timeless being given presentism), so God can cause A to persist from t1 to t2 and B to persist from t2 to t3. Thus, fundamental links in diachronic causal explanations depend on divine conservation.

An existential inertia view also gives a solution, but a far inferior one. For existential inertia requires the earlier existence of A, together with the metaphysical principle of existential inertia, to explain the later existence of A. But such a cross-time explanatory relation seems too much like the already rejected idea of cross-time causation. For it’s looking like A qua existing at t1 explains A existing at t2. But at t2, according to presentism A qua existing at t1 is in the unreal past, and it is absurd to suppose that what is in the unreal past can explain something real now.

In summary, given presentism, all fundamental explanatory relations need to be simultaneous. But it is an evident fact that there are diachronic causal explanatory relations. The only way to build those out of simultaneous explanatory relations is by supposing a being that can be simultaneous with things that exist at more than one time—a timelessly eternal being—whose causal efficacy provides the diachronic aspects of the explanatory linkage.

That said, I think there are two serious weaknesses in this story. The first is that it’s a close cousin of occasionalism. For there is no purely non-divine explanatory chain from the setting of the alarm at night to the alarm going off in the morning—divine action explains the persistences that make the chain diachronic.

A second problem is the puzzle of what explains why A causes B at t2 rather than as soon as A comes into existence. Why does A “wait” until t2 to cause B? Crucial to the story is that A is the whole cause, which then persists from t1 to t2. But why doesn’t it cause B right away, with B then causing whatever effect it has right away, and with everything in the whole causal history of the universe happening at once? Again, one might give this an occasionalist solution—A causes B only because God cooperates with creaturely causation, and God might hold off his cooperation until t2. But this makes the story even more occasionalist, by making God involved in the timing of causation.


Wesley C. said...

How exactly is this presentist conservation story similar to occasionalism just because a full explanation of the causal chain requires one to include God's conservation of it? If one accepts that God conserves things in existence at every moment, then a truly complete causal account would have to include God's conservation in it as well. Of course, you could exclude this consideration when analysing the created causal chain by itself without further reference to what's outside it ontologically, which implies that God's causality and created causality are categorically different aspects of reality and one doesn't necessarily have to make direct reference to it or even be aware of it directly.

But the same can be said of the clock alarm being set and going off - while it's true God's conservation is an important element of a full account of the whole causal picture, you can easily understand the causal link between the two without reference to divine sustaining, and don't need to be explicitly or directly aware of God's conservation if you want to focus solely on the secondary created causal aspects of it.

Alexander R Pruss said...

God *supplies* some of the links rather than explaining the links.

At t1, A exists. At t2, A exists and causes B. At t3, B still exists.

The connection between A existing at t1 and B existing at t3 consists of three explanatory links.

Let W = A existing at t1. X = A existing at t2. Y = B existing at t2. Z = B existing at t3.

Then we have three explanatory links:
1. W explains X.
2. X explains Y.
3. Y explains Z.

The "explains" in 2 involves creaturely powers, while in 1 and 3 it involves divine power alone. Thus, if we take out the links powered by God alone, we are left with a hole.

Take analog alarm clock. At night, you set the alarm clock for 7:30, by moving a red hand to the "7:30" position. That hand persists overnight in its position (i.e., both the substances the hand is made of and their positional accidents persist). In the morning, the clock's moving hour hand makes contact with the red hand, which triggers an alarm. Roughly, then, we have these three explanatory links that take us from evening to morning:
1. Because you turned a knob, the red hand got located at the 7:30 position in the evening.
2. Because the red hand was located at the 7:30 position in the evening, it was also located at the 7:30 position at 7:30 in the morning.
3. Because the red hand was located at the 7:30 position at 7:30 in the morning, the alarm went off.
Here we have three explanatory links. Links (1) and (3) involve creaturely causal explanation, but link (2) has no creaturely explanation, but is purely explained by divine conservation.

Another way to see that this is occasionalist is to imagine an eternalist theistic alternative that involves a limited amount of causal existential inertia. In this alternative, for many classes of objects, an object's existing at an earlier time causes the object to exist at a later time via primitive diachronic causation. This causation, like all creaturely causation, involves both creaturely causation but requires divine "primary causal" cooperation. On this alternative, each of the three links in the alarm story has a divine "primary causal" explanation and a creaturely "secondary causal" explanation. There is no occasionalism. But once you remove the creaturely "secondary causal" story from link (2) in the alarm story, you obviously have partial occasionalism. And that impoverished story is what the presentist divine conservation theorist tells us.

(On reflection, it seems that Catholics at least are committed to *some* partial occasionalism. Namely, we are committed to God alone being the cause of the human soul. But that's because there is something exceeding mere nature in human beings--there is something spiritual. But it would seem to be problematic to suppose that *every* diachronic explanation has occasionalist links.)

Wesley C. said...

I don't see the problem though - primary causality is by definition an aspect of causality in the created order that belongs to God, and so some things involve only divine causation. The existence of A at t1 is something that can only involve God's divine causation, insofar as its existence is considered absolutely. Even if the prior temporal existence of A somehow explains or even causes its existence later, it can only do so in a qualified way for other aspects of its existence, not in an absolute sense which belongs solely to God. So the absolute sense involves only divine causation.

So I don't think this is as occasionalistic as it seems to be.

RunDec said...

Doesn't B theory/eternalism make divine conservation, if not false, at least superfluous? If you think things could carry on existing by causing their later-selves (under B theory), why should God bother "conserving" anything at all, and why is there so much stress in dogma and traditional teaching on the doctrine that God conserves everything in being at all times, and if not for his *conservation* things would cease to be?

Alexander R Pruss said...

But causation itself requires divine concurrence according to classical theism.

Alexander R Pruss said...

I ameliorate the occasionalism worry here: