Having multiple sufficient causes

It would be useful for discussions of causal exclusion arguments for physicalism to have a full taxonomy of the kinds of cases in which one effect E can have two sufficient causes C₁ and C₂.

Here is my tentative list of the cases:

1. Overdetermination: C₁ and C₂ overdetermine E

2. Chaining: C_i sufficiently causes C_j which sufficiently causes E (where i = 1 and j = 2 or i = 2 and j = 1)

3. Constitution: C_i sufficiently causes E by being partly constituted by C_j which sufficiently causes E (where i = 1 and j = 2 or i = 2 and j = 1)

4. Parthood: C_i sufficiently causes E by having the part C_j which sufficiently causes E (where i = 1 and j = 2 or i = 2 and j = 1).

If parthood is a special case of constitution, then (4) is a special case of (3). Moreover (2)–(4) are all species cases of:

5. Instrumentality: C_i sufficiently causes E by means of C_j sufficiently causing E (where i = 1 and j = 2 or i = 2 and j = 1).

Note that the above cases are not mutually exclusive. We can, for instance, imagine a case where we have both chaining and overdetermination. Let’s say I aim a powerful heat gun at a snowball. Just in front of the snowball is a stick of dynamite. The heat melts the snowball. But it also triggers an explosion which blows the snowball apart. Thus, we have overdetermination of the destruction of the snowball by two causes: heat and explosion. However, we also have chaining because the heat causes the explosion.

I wonder if we can come up with an argument that (1)–(4), or maybe (1) and (5), are the only options. That seems right to me.

The General Composition Question

Peter van Inwagen distinguishes the General Composition Question (GCQ), which is to give necessary and sufficient conditions for the claim that the xs compose y without mereological vocabulary, from the Special Composition Question (SCQ), which is to give non-mereological necessary and sufficient conditions for the claim that there is a y such that the xs compose y again without mereological vocabulary. He thinks that he can answer the SCQ as:

1. The xs compose something iff there is exactly one x or the activity of the xs constitutes a life.

But he doesn’t try to give an answer to the GCQ, and suspects an answer can’t be given.

It is now seeming to me that van Inwagen should give a parallel answer to GCQ as well:

2. The x compose y iff the xs compose* y.

3. The xs compose* y iff every one of the xs is a part* of y and everything that overlaps* y overlaps* at least one of the xs.

4. x overlaps* y iff x and y have a part* in common.

5. x is a part* of y iff x = y or x’s activity constitutes engagement in the life of y.

Here, (3) and (4) mirror the standard mereological definition of composition and overlap, but with asterisks added. The asterisked concepts, however, bottom out in non-mereological concepts.

One might worry that constitution is a mereological concept. But if it is, then van Inwagen’s answer to the SCQ is also unsatisfactory because it uses constitution.

I feel that (2)–(5) might have some simple counterexample, but I can’t see one (or at least not one that isn't also a counterexample to van Inwagen's answer to the SCQ).

By the way, there is a cheekier answer to the GCQ:

6. The xs compose y iff the xs and y satisfy the predicate “composes” of the actual world’s late 20th century philosophical English language.

Note that here the response does not make any use of mereological vocabulary, since “‘composes’” (unlike “composes”) is not a piece of mereological vocabulary, but a piece of metalinguistic vocabulary.

Causal theories of normative statuses

Utterances cause a variety of outcomes. For instance, a request often causes an action by another person, while saying “Alexa, turn on the lights” can cause the lights to turn on. This is not the paradigmatic thing that happens with performatives. With performatives, the outcome is (at least partially) constituted by the utterance. When the Queen utters the words of knighting, the newly created knight’s knightliness is not caused by but constituted by the utterance. One plausible argument for this is that causation has a speed of light limit, but knighting does not: the Queen could knight someone a light-year away, effective immediately.

So we have two kinds of outcome for an utterance: causal outcomes and constituted outcomes. It is plausible that sometimes utterances have both kinds. For instance, knighting someone can both constitute them as a knight and cause them to do knightly deeds.

It is widely, though perhaps often only implicitly, held that the normative statuses involved in marriages, promises and reasons of request are constituted outcomes of performative utterances.

It is, I think, worth thinking about what reasons we have to accept this performative constitution thesis. For here is another possibility: these social statuses are constituted by contingent normative properties that are caused to exist by the utterance. In such a case, the utterances producing these statuses are not performatives, but function causally, like the “Alexa, turn on the light” example.

If naturalism is true, so is the performative constitution thesis. For if naturalism is true, then normative properties supervene on physical properties, and there is no plausible physical property that is caused by uttering a promise on which the relevant normative property could supervene. Here is a quick argument: Any physical property that can be produced by promising can be produced impersonally by random quantum phenomena, but such random quantum phenomena will not result in the relevant normative properties of promise. Hence the physical act of promising must be a part of the supervenience base of the relevant normative properties.

But if naturalism is false, then we have a new possibility. It could be that marrying, promising and requesting non-physically cause relevant normative properties. The quick argument above no longer works, since random quantum phenomena need not have the power to produce these normative properties. In fact, even the speed-of-light argument concerning knighting doesn’t work, because non-physical causation need not have a speed-of-light limit.

Do we have good reason, beyond an incredulous stare, to dismiss the causal theory of these normative statuses?

I think classical theists have some reasons to opposed the causal theory. First, God has the power to directly cause all the kinds of effects we have the power to cause. So if I can cause myself to have the normative property of having promised you a dollar, God can directly cause me to have his normative property. But that’s absurd: for while God can directly cause me to promise you a dollar, it is a contradiction for the state of having promised to be caused by any means other than the making of that promise.

This is, however, only a limited opposition to the causal theory. For while God cannot directly cause me to be in a promissory state, it may well be that God can directly cause me to have the paradigmatic normative property constituting the promissory state, namely an obligation of performance with exactly the kind of weight that the promise carried. Thus, the first argument is compatible with a hybrid causal-constitutive view on which my making a promise causes the obligation but constitutes the obligation as a promissory one. Compare how my carving a statue would cause the statue but constitute it as hand-made.

The second argument against the causal theory is this. By divine simplicity, God’s contingent properties are all constituted by contingent entities outside of himself. But when God promises something, he acquires a contingent obligation. By divine simplicity, that obligation must be constituted by something contingent outside of God. And the most plausible candidate is that the it is constituted by the physical manifestation making up the promise (e.g., the voice that the promisee heard). So in the case of divine promises, neither the original causal theory nor the hybrid theory is plausible.

That said, the second argument is not very strong. For contingent beliefs are internally constituted in us and yet by exactly the same divine simplicity argument externally constituted in God. So while the fact that God’s promissory normative statuses are externally constituted gives us some reason to think ours are, this is far from conclusive. Moreover, what goes for promises may not go for other things. God (qua God) cannot marry. So the argument doesn’t apply to marriage.

In summary, if naturalism is false, then it could be the case that some of the normative statuses that are generally thought to be constituted by performative utterances are in fact caused by utterances, though classical theists have some reason to prefer the performative constitution theory in many cases.

Finally, note that there is a third option besides constitution and causation: something I call quasi-causation. If I pray for an effect, and as an outcome of my prayer, God produces the effect, I don’t want to say that my prayer caused God to produce the effect. It just seems contrary to divine transcendence to suppose we can cause God to do things. Yet there is something like causation going on here. Similarly, it could be that sometimes a normative status is not caused but merely quasi-caused by an utterance.

Catholics, in fact, are liable to think that the quasi-causal theory is at least true of one aspect of one case: sacramental marriage. In sacramental marriage, there is an intrinsic change in the parties entering the marriage as a result of the exchange of the marriage vows. But because the change happens due to God’s gracious activity, it probably cannot be said to be caused by the marriage vows. Rather, the change is quasi-caused by the marriage vows. However, it is not clear whether the relevant intrinsic change is a change with respect to a normative property.

All in all, there are many open questions here.

Parts

Let us suppose that there is a proper part P of me such that every part of me beyond P could perish, while P would remain. Some think the soul is such a part. Others think the brain is. Yet others might think that the head, or the head plus soul, or my upper half are such. Suppose now that at t₀, this part P is a proper part of me, but later, at t₁, everything making me up outside of P perishes, and no new stuff accretes, so that P is my only part, at least not counting the subparts of P. Maybe I am a brain in a vat or a disembodied soul at t₁.

What is my relationship to P at t₁? It cannot be identity. For if I were identical to P at t₁, then by transitivity, I would also be identical to P at t₀, and thus at t₀ I would be a proper part of myself, which is absurd. Yet at t₁, there is a sense in which there is nothing to me but P.

It seems that if identity is not the relation, then the relation is constitution, or some other such relation that falls short of identity. Thus, I am constituted by P at t₁. This is pretty standard. But it bothers me. Here's why. At t₁, P is still a part of me--it didn't cease to be a part of me just because all the other parts of me have gone away (e.g., if I have a brain, then a brain is a part of me, even if nothing beyond it is). Is P a proper or improper part? If a proper part, then there ought to be other stuff beyond P making me up. But ex hypothesi, at t₁, P is all that's left of me. So P is an improper part. But the only improper parts of something are the thing as a whole and, on some views, nothing (or an empty or trivial part). Plainly P is not nothing. So then P is the whole of me, which we've already seen isn't true. Either way, we have a problem.

To rephrase, suppose:

1. Everything excepting some proper part of me could perish with nothing new accreting to me, and with that part not coming to be beyond me.
2. If a part x of y survives and y survives, and x does not come to be beyond y, then x will still be a part of y.
3. Identity is transitive.
4. If x is a proper part of y, then there is stuff beyond x in y.

Then a contradiction follows. (I may have forgotten some assumption here from the informal argument. But the basic idea is here.)

A slightly different argument is to note that at t₀, both P and I are parts of me in the same sense--one a proper and the other an improper part. (One might question this: maybe proper and improper parts are "parts" by analogy or equivocation.) This shouldn't change at t₁: both P and I should still be parts of me in the same sense. But it doesn't seem categorially right to suppose that x and y can both be parts of z in the same sense when x constitutes y (the atoms of my heart and my heart are parts of me in different senses).

I am inclined to say that these arguments push one to reject (1)--the idea that I have a proper part such that everything beyond that part could perish while I survived with that one part. However, I also think that if any object has proper parts, surely there will be some object with a proper part that is such that the object could survive being "reduced to" that part. Indeed, very plausibly, if any object has proper parts, likewise my mind is a proper part of me, and I could surivve being "reduced to" just the mind (regardless whether the mind is a brain or a soul).

And so we have another argument for the denial of the thesis that some objects have proper parts.