Thomism and presentism

According to Thomism:

1. That I exist is explanatorily prior to all the other facts about me.

Obviously:

2. That yesterday I safely crossed a street is explanatorily prior to the fact that I presently exist.

3. If presentism is true, the fact that I presently exist is the same fact as that I exist.

4. There are no circles of explanatorily priority.

5. That yesterday I safely crossed a street is a fact about me.

It logically follows from these that:

6. Presentism is not true.

(For from 2 and 3, if presentism is true, that I safely crossed a street is prior to the fact that I exist. But by 1 and 5 that I exist is prior to the fact that I exist. If presentism is true, we thus have a priority circle, so by 4, we don’t have presentism.)

Aquinas and Descartes on substance dualism

Roughly, Aquinas thinks of a substance as something that:

1. is existentially independent of other things, and

2. is complete in its nature.

There is a fair amount of work needed to spell out the details of 1 and 2, and that goes beyond my exegetical capacities. But my interest is in structural points. Things that satisfy (1), Aquinas calls “subsistent beings”. Thus, all substances are subsistent beings, but the converse is not true, because Aquinas thinks the rational soul is a subsistent being and not a substance.

Descartes, on the other hand, understands substance solely in terms of (1).

Now, historically, it seems to be Descartes and not Thomas who set the agenda for discussions of the view called “substance dualism”. Thus, it seems more accurate to think of substance dualists as holding to a duality of substance in Descartes’ sense of substance than in Aquinas’.

But if we translate this to Thomistic vocabulary, then it seems we get:

3. A “substance dualist” in the modern sense of the term is someone who thinks there are two subsistent beings in the human being.

And now it looks like Aquinas himself is a substance dualist in this sense. For Aquinas thinks that there are two subsistent beings in Socrates: one of them is Socrates (who is a substance in the Thomistic sense of the word) and the other is Socrates’ soul (which is a merely subsistent being). To make it sound even more like substance dualism, note that Thomas thinks that Socrates is an animal and animals are bodies (as I have learned from Christopher Tomaszewski, there are two senses of body: one is for the material substance as a whole and the other is for the matter; it is body in the sense of the material substance that Socrates is, not body in the sense of matter). Thus, one of these subsistent beings or substances-in-the-Cartesian-sense is a body and the other is a soul, just as on standard Cartesian substance dualism.

But of course there are glaring difference between Aquinas’ dualism and typical modern substance dualisms. First, and most glaringly, one of the two subsistent beings or Cartesian substances on Aquinas’s view is a part of the other: the soul is a part of the human substance. On all the modern substance dualisms I know of, neither substance is a part of the other. Second, of the two subsistent beings or Cartesian substances, it is the body (i.e., the material substance) that Aquinas identifies Socrates with. Aquinas is explicit that we are not souls. Third, for Aquinas the body depends for its existence on the soul—when the soul departs from the body, the body (as body, though perhaps not as matter) perishes (while on the other hand, the soul depends on the matter for its identity).

Now, let’s move to Descartes. Descartes’ substance dualism is widely criticized by Thomists. But when Thomists criticize Descartes for holding to a duality of substances, there is a danger that they are understanding substance in the Thomistic sense. For, as we saw, if we understand substance in the Cartesian sense, then Aquinas himself believes in a duality of substances (but with important structural differences). Does Descartes think there is a duality of substances in the Thomistic sense? That is not clear to me, and may depend on fine details of exactly how the completeness in nature (condition (2) above) is understood. It seems at least in principle open to Descartes to think that the soul is incomplete in its nature without the body or that the body is incomplete in its nature without the soul (the pineal gland absent the soul sure sounds incomplete) or that each is incomplete without the other.

So, here is where we are at this point: When discussing Aquinas, Descartes and substance dualism we need to be very careful whether we understand substance in the Thomistic or the Cartesian sense. If we take the Cartesian sense, both thinkers are substance dualists. If we take the Thomistic sense, Aquinas clearly is not, but it is also not clear that Descartes is. There are really important and obvious structural differences between Thomas and Descartes here, but they should not be seen as differences in the number of substances.

And here is a final exegetical remark about Aquinas. Aquinas’ account of the human soul seems carefully engineered to make the soul be the sort of thing—namely, a subsistent being—that can non-miraculously survive in the absence of the substance—the human being—that it is normally a part of. This makes it exegetically probable that Aquinas believed that the soul does in fact survive in the absence of the human being after death. And thus we have some indirect evidence that, in contemporary terminology, Aquinas is a corruptionist: that he thinks we do not survive death though our souls do (but we come back into existence at the resurrection). For if he weren’t a corruptionist, his ontology of the soul would be needlessly complex, since the soul would not need to survive without a human being if the human being survived death.

And indeed, I think Aquinas’s ontology is needlessly complex. It is simpler to have the soul not be a subsistent being. This makes the soul incapable of surviving death in the absence of the human being. And that makes for a better view of the afterlife—the human being survives the loss of the matter, and the soul survives but only as part of the human being.

A pre-established harmony with genuine mind-world causation

Molinists have the ability to give a distinctive pre-established harmony account of how the exceptionless truth of deterministic laws of nature could be made compatible with libertarianism.

Here is the story. God considers possible worlds where dualistic agents have the causal power to miraculously contradict the physical laws in their free choices, but where outside of exercises of free will, there are elegant deterministic mathematical laws governing the world. Call such worlds Candidate Worlds.

God then narrows his consideration to Finalist Worlds, which are Candidate Worlds that are feasible—i.e., compatible with the Molinist conditionals—and where as it happens the agents’ free choices accord with the elegant deterministic mathematical laws that govern the rest of the world.

And then God wisely and prudently chooses one of the Finalist Worlds for actualization.

On this story, there are elegant deterministic mathematical laws of nature which are true even of the agents’ choices, but they are true of the agents’ choices because the agents freely chose as they did. The agents had the causal power to violate, say, the conservation of momentum, but in fact freely did not do so.

There is an ambiguity in the concept of “exceptionless laws”. “Exceptionless laws” could mean: laws that allow no exception (they are pushy laws that are so strong as to make no exception possible) and laws that in fact have no exception. The deterministic laws in this story are exceptionless in the sense of having no exception, which is why I am talking of their exceptionless truth rather than their exceptionless power.

In this story, there is a dual explanation of the agents’ choices. On the one hand, there is a standard libertarian story about the agents’ free causality. On the other hand, the laws have explanatory power, because God chose the Finalist Worlds because they are worlds where the laws have exceptionless truth.

The big difficulty with the above story is Molinism. Also, it is worth noting that it is metaphysically possible that there turn out not to be any (feasible) Finalist Worlds: in that scenario, God wouldn’t be able to create a world where there is freedom and elegant deterministic mathematical laws holding exceptionlessly. But for reasons similar to why many people think Transworld Depravity is unlikely to be true, I think it is unlikely that there would be no Finalist Worlds.

It is also interesting to note that there are two more views that could be plugged into the story that can do the same job: Thomism and compatibilism.

On Thomism, God can use primary causation to make agents freely choose as he desires. Then we can suppose that God surveys the same Candidate Worlds as on the Molinist story. Then he chooses Finalist Worlds as those Candidate Worlds where the agents’ free choices in fact do not contradict the mathematical laws. And then God uses primary causation to actualize one of the Finalist Worlds. Again, the agents have the power to contradict the laws, but freely choose not to exercise it.

Finally we have straightforward compatibilism. A dualist can just as easily be a compatibilist as a materialist. On this story, we skip the Candidate Worlds, and the Finalist Worlds are worlds with compatibilist agents, with a deterministic non-physical mental life, who have the power of contradict the physical laws of the world but who are mentally determined, in a way compatible with freedom, never to exercise such a power. And then God chooses one of the Finalist Worlds. The agents then are as free as any compatibilist agents.

The compatibilist version of this story is close to Leibniz’s pre-established harmony, except that it has real mind-world causation, which is a big improvement.

Of course, the non-theist can’t make any of these moves. And, alas, neither can I, since my mere foreknowledge view denies Molinism, Thomism (about free will) and compatibilism.

The analogy of being and the moving spotlight theory of time

On moving spotlight theories, eternalism is true: past, present and future things all exist. But the present is metaphysically special: you have not said all that is to be said about temporal reality if you just said what happens at which times, and how the times are related by relations like earlier-than and simultaneous-with, without having said which time is objectively present. The puzzle for moving spotlight theories is to say what makes the present special.

Here is a start of a moving spotlight theory. Start with the Thomistic insight that there are multiple ways of existing. For instance, God doesn’t exist in the same way in which we do. Now add that temporal beings have three ways of existing: existing pastly, existing presently and existing futurely. Thus, we have at least four ways of existing: divine existence as pure act, past existence, present existence and future existence. These are genuinely different forms of existence, but they are all analogous. And we further subdivide the three temporal ways of existing into substantial and accidental existence.

Moreover, interestingly, these ways of existing can occur in various combinations. For instance, I exist pastly, presently and futurely. An object in the last moment of its existence exists pastly and presently. An object in the first moment of its existence exists presently and futurely. At the first moment of the Incarnation, the Second Person of the Trinity existed as pure act, as well as both presently and futurely. Right now, the Second Person of the Trinity exists in each of these four ways of being.

So what sets out the present as special is this: an event is present provided that the substances and accidents making up the event exist in present ways of existing.

This is eternalism and not presentism, but it captures one central insight of presentism: that to exist presently is different in kind from existing pastly or futurely. It escapes the three horse argument against presentism by saying that the real horses exist analogously to each other but the unreal one does not exist at all.

Of course, this is only a start. It would be nice to be able to say something substantive about how the three temporal ways of existing differ from one another. I don’t know that this can be done, and I don’t particularly want to pursue this, since I much prefer the elegance of the B-theory of time.

Molinism and Thomism and control over others

1. It is not possible for a creature to exercise complete control over another person’s (non-derivatively) free action.

2. If Molinism is true, it is possible for a creature to exercise complete control over another person’s (non-derivatively) free action.

3. So, Molinism is false.

For, if Molinism is true, there will be a possible situation where God reveals to Alice that if she were to make a request of Bob while wearing blue gloves, Bob would acquiesce to the request, but if she were to make the request while wearing red gloves, Bob would turn down the request. In such a case, by controlling which gloves she wears, Alice could exercise complete control over whether Bob acquiesces to the request.

Interestingly the same argument works against Thomism. For on Thomism, God can use primary causation to determine Bob to freely acquiesce in the request and God can use primary causation to determine Bob to freely refuse the request. God could then promise Alice that he would hear her prayers as to whether Bob agrees or refuses, and then with her prayers, Alice would have complete control over Bob's decision.

The argument doesn't work against mere foreknowledge views, open theist views or compatibilist views. On mere foreknowledge and open theism, the analogue of (2) is false, while on compatibilism, (1) is not plausible.

God, probabilities and causal propensities

Suppose a poor and good person is forced to flip a fair and indeterministic coin in circumstances where heads means utter ruin and tails means financial redemption. If either Molinism or Thomism is true, we would expect that, even without taking into account miracles:

1. P(H)<P(T).

After all, God is good, and so he is more likely to try to get the good outcome for the person. (Of course, there are other considerations involved, so the boost in probability in favor of tails may be small.)

The Molinist can give this story. God knows how the coin would come out in various circumstances. He is more likely to ensure the occurrence of circumstances in which the subjunctive conditionals say that tails would comes up. The Thomist, on the other hand, will say that God’s primary causation determines what effect the secondary creaturely causation has, while at the same time ensuring that the secondary causation is genuinely doing its causal job.

But given (1), how can we say that the coin is fair? Here is a possibility. The probabilities in (1) take God’s dispositions into account. But we can also look simply at the causal propensities of the coin. The causal propensities of the coin are equibalanced between heads and tails. In addition to the probabilities in (1), which take everything including God into account, we can talk of coin-grounded causal chances, which are basically determined by the ratios of strength in the causal propensities. And the coin-grounded causal chances are 1/2 for heads and 1/2 for tails. But given Molinism or Thomism, these chances are not wholly determinative of the probabilities and the frequencies in repeat experiments, since the latter need to take into account the skewing due to God’s preference for the good.

So we get two sets of probabilities: The all-things-considered probabilities P that take God into account and that yield (1) and the creatures-only-considered probabilities P_c on which:

2. P_c(H)=P_c(T)=1/2.

Here, however, is something that I think is a little troubling about both the Molinist and Thomist lines. The creatures-only-considered probabilities are obviously close to the observed frequencies. Why? I think the Molinist and Thomist have to say this: They are close because God chooses to act in such ways that the actual frequencies are approximately proportional to the strengths of causal propensities that P_c is based on. But then the frequencies of coin toss outcomes are not directly due to the causal propensities of the coin, but only because God chooses to make the frequencies match. This doesn’t seem right and is a reason why I want to adopt neither Molinism nor Thomism but a version of mere foreknowledge.

A Thomistic argument for essentiality of origins

Here is a suggestive Thomistic line of thought in favor of the essentiality of origins—i.e., the principle that the causes of things are essential to them.

Consider two possible cases where a seed is produced in the same apple tree T:

1. A seed is produced at t because of the tree’s exercise of seed-producing powers together with God’s cooperative exercise of primary causation.

2. A seed is created directly at t by God and not by the exercise of the tree’s powers.

And suppose that the seeds in the two cases are exactly alike, occur in the same place on the tree, etc.

I will argue that the Thomist should say that these will be numerically different seeds, and the best explanation of their difference is given by essentiality of origins.

For the Thomist is committed to there being a genuine difference between the two cases. Cooperative divine-creaturely causality is metaphysically different from divine primary causality. But where does the difference lie? Well, in (1) the tree’s causal powers are activated, while in (2) they are not. But it is a standard scholastic maxim that the effect is the actuality of the cause qua cause. Thus it seems that the difference between cases (1) and (2) should be found in the effect, namely the seed.

Furthermore, suppose that the difference between the cases is solely located in the cause, namely that in case (1) the tree’s causal powers are activated but not in (2), and that this activation is an accident A of the tree. The difference between cases (1) and (2) then is that in case (1), A occurs in the tree and in case (2) it does not. But for any accident of the tree, God could miraculously suppress any effects of that accident. Thus, there will be a case where A occurs in the tree and no seed results. And we could, further, imagine that:

3. Not only does God suppress the effects of A but he additionally directly miraculously produces an effect exactly like the one that A would have produced.

The difference between (3) and (1) can’t be in the activation of the tree’s causal power, since that is still there in (3). So we really should suppose a difference in the effects between (3) and (1). But a similar difference should exist between (2) and (1).

Note that the Thomist cannot say that there is a difference on the side of the causes lies in God, namely that in case (1), God’s causal power is unactivated but it is activated in (2) and (3). For an intrinsic difference in God between possible worlds would violate divine simplicity.

Thus, it is the effects, namely the seeds, that are numerically different, and they are different precisely because their causes are different. But the seeds are exactly alike. So the difference must be a metaphysical difference between the seeds. And this strongly suggests essentiality of origins. Indeed, it suggests that entities have encoded within them the identity of their cause.

Objection: The argument at most suggests that there has to be a numerical difference when something is produced by a finite cause (with God cooperating) and when something is produced directly by God. But why think there is also a difference when the effect is produced by one finite cause rather than another?

Response: The simplest metaphysical explanation of why it makes a difference whether God produces the effect or it is produced by finite causes is that the effect has metaphysically encoded in it what its cause was. In fact, my own view is that this may be found in the effect’s esse: perhaps an effect’s esse is to be caused by this-and-that.

Moreover, suppose that there need be no numerical difference between effects of different finite causes, but there is a numerical difference between direct effects of divine causation and the effects of finite causes. Then in principle scientists could have directly made the numerically same seed that the tree made in (1), but God couldn’t have directly made the numerically same seed. That seems unacceptable. (Of course, one might rejoin that essentiality of origins is unacceptable as it implies that God couldn’t directly make the numerically same seed that the tree could make. But when, as I suppose, an effect of necessity encodes in itself what its cause is, the impossibility of something’s being made by a different cause does not seem to be a limitation on that cause.)

Thomism, chance and cooperative providence

Thomists have two stories about how God can act providentially in the world. First, God can work simply miraculously, directly producing an effect that transcends the relevant created causal powers. Second, God can work cooperatively: whenever any finite causal agency is exercised, God intentionally cooperates with it through his primary causation, in such a way that it is up to God which of the causal agents natural effects is produced.

I think there is a difficult problem for cooperative divine agency. Suppose Alice is desperate for food for her children. She finds an indeterministic alien device which has the following property. If she presses the big button on it, the machine has probability 1/2 of producing enough food for a month for her family, and probability 1/2 of giving her a mild shock and turning off for a month.

Alice says a quick but sincerely prayer and presses the button. Then, presumably:

1. The probability that the machine will produce food is 1/2 conditionally on God not working miraculously.

But now notice:

2. Necessarily, if God does not work miraculously, the machine will produce food if and only if God intentionally connaturally cooperates with the machine to produce food.

From (1) and (2) we can conclude:

3. The probability that God will intentionally cooperates with the machine to produce food is 1/2 conditionally on God not working miraculously.

But imagine a different machine, where pressing the button has probability 1/2 of producing enough round pizza for a week and probability 1/2 of producing enough square pizza for a week. If Alice pressed the button on that machine, God, in acting cooperatively, would not have any significant reason to make the output of the machine come out one way or another.

In the round-or-square-pizza machine, we would expect the probability that God would cooperate to produce a particular outcome to be 1/2. But in the food-or-nothing machine, God does have a good reason to make the output of the machine be food: namely, God loves Alice and her family. We would expect the statistics for divine intentional cooperation to be different in the case of the two machines. But they are the same. In other words, it seems that God’s cooperative providence cannot depart from the statistics built into the natures of creatures. Yet that providence is fully under God’s voluntary control according to Thomism. This is puzzling.

If the Thomist says that God’s special providence is always exercised miraculously rather than cooperatively, the problem disappears. Absent special providential reasons, God has reason to follow the natural statistics of the machines. But if we allow that God sometimes exercises his special providence cooperatively, that should skew the statistics, and it cannot do that given the argument from (1) and (2) to (3).

Restricting special providence to miracles is a real option, but it destroys one of the advantages that Thomism has over competing theories.