Theistic Humeanism?

Here’s an option that is underexplored: theistic Humeanism. There are two paths to it.

The path from orthodoxy: Start with a standard theistic concurrentism: whenever we have a creaturely cause C with effect E, E only eventuates because God concurs, i.e., God cooperates with the creaturely causal relation. Now add to this a story about what creaturely causation is. This will be a Humean story—the best I know is the David Lewis one that reduces causation to laws and laws to arrangements of stuff. Keep all the deep theistic metaphysics of divine causation.

The path from heterodoxy: Start with the metaphysics of occasionalism. Don’t change any of the metaphysics. But now add a Humean analysis of creaturely causation in terms of regularities. Since the metaphysics of occasionalism affirms regularities in the world, we haven’t changed the metaphysics of occasionalism, but have redescribed it as actually involving creaturely causation.

The two paths meet in a single view, a theistic Humeanism with the metaphysics of occasionalism and the language of concurrentism, and with creaturely causation described in a Humean way.

This theistic Humeanism is more complex than standard non-theistic Humeanism, but overcomes the central problem with non-theistic Humeanism: the difficulty of finding explanation in nature. If the fact that heat causes boiling is just a statement of regularity, it does not seem that heat explains boiling. But on theistic Humeanism, we have a genuine explanatory link: God makes the water boil because God is aware of the heat.

There is one special objection to theistic Humeanism. It has two causal relations, a divine one and a creaturely one. But the two are very different—they don’t both seem to be kinds of causation. However, on some orthodox concurrentisms, such as Aquinas’s, there isn’t a single kind of thing that divine and creaturely causation are species of. Instead, the two stand in an analogical relationship. Couldn’t the theistic Humean say the same thing? Maybe, though one might also object that Humean creaturely causation is too different from divine causation for the two to count as analogous.

I suppose the main objection to theistic Humeanism is that it feels like a cheat. The creaturely causation seems fake. The metaphysics is that of occasionalism, and there is no creaturely causation there. But if theistic Humeanism is a cheat, then standard non-theistic Humeanism is as well, since they share the same metaphysics of creaturely causation. If non-theistic Humeanism really does have causation, then our theistic Humeanism really does have creaturely causation. If one has fake causation, so does the other. I think both have fake causation. :-)

Change and matter

Aristotle’s positing matter is driven by trying to respond to the Parmenidean idea that things can’t come from nothing, and hence we must posit something that persists in change, and that is matter.

But there two senses of “x comes from nothing”:

1. x is uncaused

2. x is not made out of pre-existing materials.

If “x comes from nothing” in the argument means (1), the argument for matter fails. All we need is a pre-existing efficient cause, which need not be the matter of x.

Thus, for the argument to work, “x comes from nothing” must mean (2). But now here is a curious thing. From the middle ages to our time, many Aristotelians are theists, and yet still seem to be pulled by Aristotle’s argument for matter. But if “x comes from nothing” means (2), then theism implies that it is quite possible for something to come from nothing: God can create it ex nihilo.

There are at least two possible responses from a theistic Aristotelian who likes the argument for matter. The first response is that only God can make things come from nothing in sense (2), and hence things caused to exist by finite causes (even if with God’s cooperation) cannot come from nothing in sense (2). But there plainly are such things all around us. So there is matter.

Now, at least one theistic Aristotelian, Aquinas, does explicitly argue that only God can create ex nihilo. But the argument is pretty controversial and depends on heavy-duty metaphysics, about finite and infinite causes. It is not just the assertion of a seemingly obvious Parmenidean “nothing comes from nothing” principle. Thus at least on this response, the argument for matter becomes a lot more controversial. (And, to be honest, I am not convinced by it.)

The second and simpler response is to say that it’s just an empirical fact that there are things in the world that don’t come from nothing in sense (2): oak trees, for example. Thus there in fact is matter. This response is pretty plausible, but can be questioned: one might say that we have continuity of causal powers rather than any matter that survives the generation.

Finally, it’s worth noting that I suspect Aristotle misunderstands the Parmenidean argument, which is actually a very simple reductio ad absurdum:

3. x came into existence.
4. If x came into existence, then x did not exist.
5. So, x did not exist.
6. But non-existence is absurd.

The crucial step here is (6): the Parmenidean thinks the very concept of something not existing is absurd (presumably because of the Parmenidean’s acceptance of a strong truthmaker principle). The argument is very simple: becoming presupposes the truth of some past-tensed non-existence statements, while non-existence statements are always false. Aristotle’s positing matter does nothing to refute this Parmenidean argument. Even if we grant that x’s matter pre-existed, it’s still true that x did not exist, and that’s all Parmenides needs. Likewise, Aristotle’s famous actuality/potentiality distinction doesn’t solve the problem. Even if x was pre-existed by a potentiality for existence, it’s still true that x wasn’t pre-existed by x—that would be a contradiction.

To solve Parmenides’ problem, however, we do not need to posit matter or potentiality or anything like that. We just need to reject the idea that negative existential statements are nonsensical. And Aristotle expressly does reject this idea: he says that a statement is true provided it says of what is that it is or of what is not that it is not. Having done that, Aristotle should take himself as done with Parmenides’ problem of change.

Causation and contingency

A correspondent yesterday reminded me of a classic objection to the “inductive” approach to the causal principle that all contingent things have causes in the context of cosmological arguments. As I understand the objection, it goes like this:

1. Granted, we have good reason to think that all the contingent things we observe do have causes. However, all these causes are contingent causes, and so we have equally good inductive support to think that all contingent things have contingent causes. Thus, to extend this reasoning to conclude that the cosmos—the sum total of all contingent things—has a cause is illegitimate, since the cosmos cannot have a contingent cause on pain of circularity.

An initial response is that (1) as it stands appears to rely on a false principle of inductive reasoning:

2. Suppose that all observed Fs are Gs, and that all observed Fs are also Hs. Then we have equally good inductive support for the hypothesis that all Fs are Hs as that all Fs are Gs.

But (2) is false. All observed emeralds are green and all observed emeralds are grue, where an emerald is grue if it is green and observed before 2100 or it is blue and not observed before 2100. It is reasonable to conclude that all emeralds are green but not that they are all grue. Or even more simply, from the facts that all observed electrons are charged and all observed electrons are observed, it is reasonable to conclude that all electrons are charged but not that all electrons are observed.

Nonetheless, this response to (1) does not seem entirely satisfying. The predicate “has a contingent cause” seems to be projectible, i.e., friendly to induction, in a way in which “is grue” or “is observed” are not.

Still, I think there is something more to be said for this response to (1). While “has a contingent cause” is not as obviously non-projectible as “is observed”, it has something in common with it. We are more suspicious of inductive inferences from all observed Fs being Gs to all Fs being Gs when being G includes features that are known prior to these observations to be concommitants of observation. For instance, consider the following variant of the germ theory of disease:

3. All infectious diseases are caused by germs that are at least 500 nm in size.

Until the advent of electron microscopy, all the infectious diseases whose causes were known were indeed caused by germs at least 500 nm in size, as that is the lower limit of what can be seen with visible light. But it would not be very reasonable to have concluded at the time that 500 nm is the lower limit on the size of a disease-causing germ. Now, something similar is happening in the contingent cause case. All observable things are physical. All physical things are contingent. So being contingent is a concommitant of being observed.

Finally, there is another epistemological problem with (1). The fact that some evidence gives as good support for q as for p does not mean that q is as likely to be true as p given the evidence. For the prior probability of q might be lower than that of p. And indeed that is the case in the reasoning in (1). The prior probability that everything contingent has a contingent cause is zero, precisely for the reason stated in (1): it is impossible that everything contingent have a contingent cause! But the prior probability that everything contingent has a cause is not zero.

Qualitative haecceities

A haecceity H of x is a property of an entity such that necessarily x exists if and only if x instantiates H.

Haecceities are normally thought of as non-qualitative properties. But one could also have qualitative haecceities. Of course, if an entity has a qualitative haecceity then it cannot be duplicated, so one can only suppose that everything has a qualitative haecceity provided one is willing to agree with Leibniz’s Identity of Indiscernibles.

I am personally drawn to the idea that everything does have a qualitative haecceity, and specifically that the qualitative haecceity of x encapsulates x’s qualitative causal history: a complete qualitative description of x’s explanatorily initial state and of all of its causal antecedents. One might call such properties “qualitative origins”. The view that every entity has a qualitative origin is a haecceity is a particularly strong version of the essentiality of origins: everything in an entity’s causal history is essential to it, and the causal history is sufficient for the entity’s existence.

I suppose the main reason not to accept this view is that it implies that two distinct objects couldn’t have the same qualitative origin, but it seems possible that God could create two objects ex nihilo with the same qualitative initial state Q. I am not so sure, though. How would God do that? “Let there be two things satisfying Q?” But this is too indeterminate (I disagree with van Inwagen’s idea that God can issue indeterminate decrees). If there can be two, there can be three, so God would have to specify which two things satisfying Q to create. But that would require a way of securing numerical reference to specific individuals prior to their creation, and that in turn would require haecceities, in this case non-qualitative haecceities. So the objection to the view requires non-qualitative haecceities.

But what started us on this objection was the thought that God could say “Let there be two things satisfying Q.” But if God could say that, why couldn’t he say “Let there be two things satisfying H”, where H is a non-qualitative haecceity? I suppose one will say that this is nonsense, because it is nonsense to suppose two things share a non-qualitative haecceity. But isn’t there a double-standard here? If it is nonsense to suppose two things share a non-qualitative haecceity, why can’t it be nonsense to suppose two things share a qualitative haecceity? It seems that “what does the explaining” of why two things can’t share a non-qualitative haecceity is the obscurity of non-qualitative haecceities, and that’s not really an explanation.

So perhaps we can just say: Having a distinct qualitative origin is what it is to be a thing, and it is impossible for two things to share one. This does indeed restrict the space of possible worlds. No exactly similar iron spheres or anything like that. That’s admittedly a little counterintuitive. But on the other hand, we have a lovely explanation of intra- and inter-world identity of objects, as well as a reduction of de re modality to de dicto, all without the mystery of non-qualitative haecceities. Plus we have Leibniz’s zero/one picture of the world on which all of reality is described by zeroes and ones: we put a zero beside an uninstantiated qualitative haecceity and a one besides an initiated one, and then that tells us everything that exists. This is all very appealing to me.

Existence and causation

Start with these plausible claims:

1. If x causes y, the causal relation between x and y is not posterior to the existence of y.

2. A relation between two entities is never prior to the existence of either entity.

So, the causal relation between x and y is neither prior nor posterior to the existence of y.

But the causal relation is, obviously, intimately tied to the existence of y. What is this tie? The best answer I know is that the causal relation is the existence of y or an aspect of that existence: for y to exist is at least in part for y to have been caused by x.

An act with a normative end

Here’s an interesting set of cases that I haven’t seen a philosophical discussion of. To get some item B, you need to affirm that you did A (e.g., took some precautions, read some text, etc.) But to permissibly affirm that you did A, you need to do A. Let us suppose that you know that your affirmation will not be subject to independent verification, and you in fact do A.

Is A a means to B in this case?

Interestingly, I think the answer is: Depends.

Let’s suppose for simplicity that the case is such that it would be wrong to lie about doing A in order to get B. (I think lying is always wrong, but won’t assume this here.)

If you have such an integrity of character that you wouldn’t affirm that you did A without having done A, then indeed doing A is a means to affirming that you did A, which is a means to B, and in this case transitivity appears ot hold: doing A is a means to B.

But we can imagine you have less integrity of character, and if the only way to get B would be to falsely affirm that you did A, you would dishonestly so affirm. However, you have enough integrity of character that you prefer honesty when the cost is not too high, and the cost of doing A is not too high. In such a case, you do A as a means to permissibly affirming that you did A. But it is affirming that you did A that is a means to getting B: permissibly affirming is not necessary. Thus, your doing A is not a means to getting B, but it is a means to the additional bonus that you get B without being dishonest.

In both specifications of character, your doing A is a means to its being permissible for you to affirm you did A. We see, thus, that we have a not uncommon set of cases where an ordinary action has a normative end, namely the permissibility of another action. (These are far from the only such cases. Requesting someone’s permission is another example of an action whose end is the permissibility of some other action.)

The cases also have another interesting feature: your action is a non-causal means to an end. For your doing A is a means to permissibility of affirming you did A, but does not cause that permissibility. The relationship is a grounding one.

Knowledge of qualia

Suppose epiphenomenalism is true about qualia, so qualia are nonphysical properties that have no causal impact on anything. Let w₀ be the actual world and let w₁ be a world which is exactly like the actual world, except that (a) there are no qualia (so it’s a zombie world) and (b) instead of qualia, there are causally inefficacious nonphysical properties that have a logical structure isomorphic to the qualia of our world, and that occur in the corresponding places in the spatiotemporal and causal nexuses. Call these properties “epis”.

The following seems pretty obvious to me:

1. In w₁, nobody knows about the epis.

But the relationship of our beliefs about qualia to the qualia themselves seems to be exactly like the relationship of the denizens of w₁ to the epis. In particular, neither are any of their beliefs caused by the obtaining of epis, nor are any of our beliefs caused by the obtaining of qualia, since both are epiphenomenal. So, plausibly:

2. If in w₁, nobody knows about the epis, then in w₀, nobody knows about the qualia.

Conclusion:

3. Nobody knows about the qualia.

But of course we do! So epiphenomenalism is false.

Overdetermining causation and prevention

Overdetermination seems to work differently for prevention and positive causation.

Suppose Timmy the turtle is wearing steel armor over his shell, because it looks cool. Alice shoots an arrow at Timmy’s back from the side, which glances off the armor. Let us assume that arrows shot at the back of an unarmored turtle from the side also harmlessly glance off the shell. Then we have two questions:

1. Did the armor prevent Timmy’s death?

2. Did the armor cause the arrow to glance off?

My intuition is that the answers are “no” and “yes”, respectively. You only count as preventing death if you are stopping something lethal. But I assumed that an arrow aimed at the back of an ordinary turtle from the side glances off the shell and is not lethal. On the other hand, it is clear that the arrow glanced off the armor, not the shell, and so it was the armor that redirected the flight.

Why the difference?

I think it may be this. There is a particular token flight-redirection event f₀ that the the armor caused. When you cause a token of a type, you automatically count as having cause an event of that type. So by causing f₀, the armor caused a flight-redirection event, a glancing-off.

However, it does not seem right to say that in preventing an event, one is causing a token non-occurrence. There would be too many non-occurrences in the ontology! Prevention is prevention of a type.

Second-order awareness

Here is a plausible Cartesian thesis:

1. There is a kind of second-order awareness of first-order conscious states that is never mistaken: whenever you have the awareness, then you have the first-order conscious state.

I don’t mean this to be true by packing factiveness into awareness.

But also plausibly:

2. A veridical awareness of an event is caused by the event it is the awareness of.

And:

3. Causation always involves a time-delay.

Given (1)–(3), suppose that you are having the second-order awareness, which is being caused byt he first-order conscious states, and then suddenly the first-order conscious state ends. Since causation always involves a time-delay, it follows that the second-order awareness lags after the end of the first-order conscious state—that there is a time at which you have the second-order awareness even though the first-order conscious state has ended. And this contradicts (1).

I am inclined to deny (1).

But there are other paths out. One could deny (2) and say that in some cases, awareness is not caused but partly constituted by the event it is the awareness of. That’s how God’s awareness of the world has to work by divine simplicity. So the argument provides a tiny bit of evidence for that picture of divine awareness.

Or one might deny (3). Apart from some phenomena like collapse of entangled quantum states or a particle’s position causing a field at the precise position of the particle, which phenomena don’t seem relevant to the case at hand, the best way out here would be to deny naturalism, allowing that a non-physical first-order awareness could instantly cause a non-physical second-order awareness.

Even more on pointy beginnings

In a recent post I argued that in Aristotelian substantial change, given special relativity, the resultant substance starts as basically a point—it is arbitrarily small.

I think the argument doesn’t actually require much in the way of Aristotelian assumptions, but works for any caused extended substance, or at least any ordinary one.

Suppose that a substance B is caused to exist by A (which might be a single entity or a plurality) and initially (at least) at distinct points in spacetime. There is a reference frame according to which one of these points is earlier than the other (this is true in all frames if the points are timelike-related and some frames if they are spacelike-related). Let F be a frame where this happens, and let z₁ be the F-earlier and z₂ the F-later point. From now on, work in F.

Let t_i be the time of z_i. Now B is at least partly present arbitrarily close to z₁, and hence arbitrarily close to t₁, and since t₁ < t₂, it follows that B already existed before t₂. Therefore, any causal influence of A sufficiently close to time t₂ is irrelevant to B’s existence. In fact, B wasn’t even partly caused by A to exist at times close to t₂, since it had already existed for a while before this. And this contradicts our assumption that A caused B at both z₁ and z₂.

A crucial assumption here is that nothing that happens later than a time t is relevant to whether a substance B exists at t.

What if there is backwards causation? If so, then this argument fails. But even if there is backwards causation, it is rare and extraordinary. It is still true that in ordinary cases, substances are caused to exist at a single point.

What if B is uncaused? Again, the argument fails. But even if there are uncaused extended substances, they are not the norm. So, again, the argument still works in ordinary cases.

A tweak to Bohmianism

I think there is a sense in which it is correct to say that:

1. Bohmian quantum mechanics is only known to work empirically if we suppose that the initial configuration of the particles is fine-tuned.

Yet there are famous results that show that:

2. For typical initial configurations, Bohmian quantum mechanics yields standard quantum Born rule predictions, which we know to work empirically.

It seems that (1) and (2) contradict each other. But that is not so. For the typicality in (2) is measured using a typicality measure P^ψ defined in terms of the initial wavefunction ψ of the universe (specifically, I believe, P^ψ(A) = ∫_A|ψ(q)|²dq for an event A). And a configuration typical relative to P^ψ₁ need not be typical relative to P^ψ₂. In fact, if ψ₁ and ψ₂ are significantly different, then a P^ψ₁-typical configuration will be P^ψ₂-atypical.

The fine-tuning I am thinking of in (1) is thus that the initial configuration of particles needs to be fitted to the initial wavefunction ψ: a configuration typical for one wavefunction is not typical for another.

I think there is an interesting solution to the Bohmian fine-tuning which I haven’t heard discussed, either because it’s crazy or because maybe nobody else worries about this fine-tuning or maybe just because I don’t talk to philosophers of quantum mechanics enough. Suppose that the wavefunction of the universe (or, more precisely, the aspect of physical reality that is representated by the mathematics of the wavefunction) has a special causal power in the first moment of its existence, and only then: an indeterministic power to produce a particle configuration, with the power’s stochastic propensities being modeled by P^ψ.

This adds a little bit of metaphysical complexity to the Bohmian story, but I think significantly increases the explanatory power in two ways: first, by giving us a proper stochastic ground for the statistic probabilities and, second, by unifying the cause of the initial particle configuration and the cause of the dynamics (admittedly at the expense of a complexity in that in that cause there is a causal power that goes away or becomes irrelevant).

(Maybe this is not necessary. Maybe there are, or can be, some typicality results that don’t require fine-tuning to the initial wavefunction. Or maybe I just misunderstand the framework of the typicality results. I don’t know much about Bohmianism.)

A variant of Thomson's Lamp

In the classic Thomson’s Lamp paradox, the lamp has a switch such that each time you press it, it toggles between on and off. The lamp starts turned off, say, before 10:00, and then the switch is pressed at 10:00, 10:30, 10:45, 10:52.5, 10:56.25, and so on ad infinitum. And the puzzle is: Is it on or off at 11? It’s a puzzle, but not obviously a paradox.

But here’s an interesting variant. Instead of a switch that toggles on or off each time you press, you have a standard slider switch, with an off position and an on position. Before 10:00, the lamp is off. At 10:00, 10:45, 10:56.25, and so on, the switch is pushed forcefully all the way to the on side. At 10:30, 10:52.5, and so on, the switch is pushed forcefully all the way to the off side.

The difference between the slider and toggle versions is this. Intuitively, in the toggle version, each switch press is relevant to the outcome—intuitively, it reverses what the outcome would be. In the slider variant, however, each slider movement becomes irrelevant as soon as the next time happens. At 10:45, the switch is pushed to the on side, and at 10:52.5, it is pushed to the off side. But if you skipped the 10:45 push, it doesn’t matter—the 10:52.5 push ensures that the switch is off, regardless of what happened at 10:45 or earlier.

Thus, on the slider version, each of the switch slides is causally irrelevant to the outcome at 11. But now we have a plausible principle:

1. If between t₀ and t₁ a sequence of actions each of which is causally irrelevant to the state at t₁ takes place, and nothing else relevant to the state takes place, the state does not change between t₀ and t₁.

Letting t₀ be 9:59 and t₁ be 11:00, it follows from (1) that the lamp is off at 11:00 since it’s off at 10:00, since in between the lamp is subjected to a sequence of caually irrelevant actions.

Letting t₀ be 10:01 and t₁ still be 11:00, it follows from (1) that the lamp is on at 11:00, since it’s on at 10:01 and is subjected to a sequence of causally irrelevant actions.

So it’s on and off at 11:00. Now that’s a paradox!

Humeanism about causation and functionalism about mind

Suppose we combine a Humean account of causation on which causation is a function of the pattern of intrinsically acausal events in reality with a functionalist account of consciousness. (David Lewis, for instance, accepted both.)

Here is an interesting consequence. Whether you are now conscious depends on what will happen in the future. For if the world were to radically change 14 billion years from the Big Bang, i.e., 200 million years from now, in such a way that the regularities that held for the first 14 billion years would not be laws, then the causal connections that require these regularities to be laws would not obtain either, and hence (unless we got lucky and new regularities did the job) our brains would lack the kind of causal interconnections that are required for a functionalist theory of mind.

This dependence of whether we are now conscious on what will happen in the future is intuitively absurd.

But suppose we embrace it. Then if functionalism is the necessary truth about the nature of mind, the fact that we are now conscious necessarily implies that the future will not be such as to disturb the lawlike regularities on which our consciousness is founded. In other words, on the basis of the fact that there are now mental states, one can a priori conclude things about the arrangement of physical objects in the future.

Indeed, this opens up the way for specific reasoning of the following sort. Given what the constitution of humans brains is, and given functionalism, for these brains to exhibit mental states of the sort they do, such-and-such generalizations must be special cases of laws of nature. But for there to be such laws of nature, then the future must be such-and-such. So, we now have a room for substantive a priori predictions of the future.

This all sounds very un-Humean. Indeed, it sounds like a direct contradiction to the Humean idea that reasoning from present to future is merely probabilistic. But while it is very counterintuitive, it is not actually a contradiction to the Humean idea. For on functionalism plus Humeanism about causation, facts about present mental states are not facts about the present—they are facts about the universe as a whole!

(This was sparked by some related ideas by Harrison Jennings.)

The Alpha and the Omega

For a long time I have thought that the identification of God as the Alpha and the Omega in the Book of Revelation is very Aristotelian: God is the efficient and final cause of all. Indeed, Revelation 22:13 explicitly glosses as he arche kai ho telos. This may initially seem an over-metaphysicalization of Scripture, but I think it is a very Scriptural idea that particular aspects of God’s involvement in the world—us being comforted (in a way) that God is the arche and the telos of the upheavals in the Book of Revelation—are mirrors of God’s innate nature.

Substances and their existences

I used to think that:

1. x is a substance just in case  <x exists> is not grounded in any fact about any other entity other than x.

But it is plausible that a finite creature’s existing is its being created. And that Alice is created seems to be grounded in God creating Alice, which seems to be a fact about God.

There is a nice response to this worry. On standard medieval views, creation is a one-way relation. When God creates Alice, there is a relation of being-created-by-God in Alice but no relation of creating-Alice in God. We can say, then, that in an important sense the fact that God creates Alice is not a fact about God, but about Alice, where we say that a fact is about x provided the fact is in part a fact of x’s existing or there being some property or relation in x.

It’s interesting that the very plausible account (1) of substance combined with a theistically plausible view that the esse of a finite thing is its being-created yields the rather abstruse one-way relation thesis.

This line of thought does not, however, fit well with the claim that I made in The Principle of Sufficient Reason that for a caused entity, its esse is its being caused. For Alice is also caused by her parents. And while divine causation may be a one-way relation, it seems unlikely that creaturely causation is.

There are three ways out of this worry. (i) We could say that creaturely causation is also a one-way relation. (ii) We could say that I was slightly wrong, and for a caused entity, its esse is its being primarily caused, i.e., caused by God. (iii) We could modify (1) to:

2. x is a substance just in case  < x exists> has a grounding in a fact that is neither about any entity other than x nor grounded in a fact about any entity other than x.

For we can then say that while Alice’s being-caused is grounded in her parents’ activity, which is a fact about her parents, it is also grounded in God’s causing Alice, which is not a fact about God in the sense of being grounded in a relation or property of God’s.

I like both (ii) and (iii). What is especially attractive about (ii) is that if the esse of Alice is her being caused, then the esse of Alice is highly disjunctive, being multiply grounded—in God’s causing Alice, in her parents causing her, in her parents’ gametes causing her, maybe even in her grandparents’ causing her, etc. But it doesn’t seem right to say that Alice’s esse is highly disjunctive. So a focus on primary causation seems attractive. And I think—but without a careful examination—that the arguments in Principle of Sufficient Reason work with that modification still.

Bidirectionality in means and ends

I never seem to tire of this action-theoretic case. You need to send a nerve signal to your arm muscles because there is a machine that detects these signals and dispenses food, and you’re hungry. So you raise your arm. What is your end? Food. What is your means to the food? Sending a nerve signal. But what is the means to the nerve signal?

The following seems correct to say: You raised your arm in order that a nerve signal go to your arm. What has puzzled me greatly about this case in the past is this. The nerve signal is a cause of the arm’s rising, and the effect can’t be the means to the cause. But I now think I was confused. For while the nerve signal is a cause of the arm’s rising, the nerve signal is not a cause of your raising your arm. For your raising your arm is a complex event C that includes an act of will W, a nerve signal S, and the rising of the arm R. The nerve signal S is a part, but not a cause, of the raising C, though it is a cause of the rising R.

So it seems that the right way to analyze the case is this. You make the complex event C happen in order that its middle part S should happen. Thus we can say that you make C happen in order that its part S should happen in order that you should get food. Then C is a means to S, and S is a means to food, but while S is a causal means to food, C is a non-causal means to S. But it’s not a particularly mysterious non-causal means. It sometimes happens that to get an item X you buy an item Y that includes X as a part (for instance, you might buy an old camera for the sake of the lens). There is nothing mysterious about this. Your obtaining Y is a means to your obtaining X, but there is no causation between the obtaining of Y and the obtaining of X.

Interestingly, sometimes a part serves as a means to a whole, but sometimes a whole serves as a means to the part. And this can be true of the very same whole and the very same part in different circumstances. Suppose that as a prop for a film, I need a white chess queen. I buy a whole set of pieces to get the white queen, and then throw out the remaining pieces in the newly purchased set to avoid clutter. Years later, an archaeologist digs up the 31 pieces I threw out, and buys my white queen from a collector to complete the set. Thus, I acquired the complete set to have the white queen, while the archaeologist acquired the white queen to have the complete set. This is no more mysterious than the fact that sometimes one starts a fire to get heat and sometimes one produces heat to light a fire.

Just as in one circumstances an event of type A can cause an event of type B and in other circumstances the causation can go the other way, so too sometimes an event of type A may partly constitute an event of type B, and sometimes the constitution can go the other way. Thus, my legal title to the white queen is constituted by my legal title to the set, but the archaeologist’s legal title to the set is partly constituted by legal title to the white queen.

There still seems to be an oddity. In the original arm case, you intend your arm’s rise not in order that your arm might rise—that you don’t care about—but in order that you might send a nerve signal. Thus, you intend something that you don’t care about. This seems different from buying the chess set for the sake of the queen. For there you do care about your title to the whole set, since it constitutes your title to the queen. But I think the oddity can probably be resolved. For you only intend your arm’s rising by intending the whole complex event C of your raising your arm. Intending something you don’t care about as part of intending a whole you do care about is not that unusual.

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.

Force-realism and simultaneous causation

If a charged particle is an electromagnetic field, the field exerts a Lorentz force F = qE + qv × B, where q and v are the charge and velocity of the particle, E is the electric field and B is the magnetic field. All of these quantities are taken at one location in spacetime. Thus, if realism about forces is correct, we have simultaneous causation: the electromagnetic field simultaneously causes the force.

Not everyone is a realist about forces, though. One might think that the electromagnetic field directly causes the subsequent change in velocity instead of causing a force which in turn causes the change in velocity.

Causing via a part

Assume this plausible principle:

1. If a part x of z causes w, then z causes w.

Add this controversial thesis:

2. For any x and y, there is a z that x and y are parts of.

Thesis (2) is a consequence of mereological universalism, for instance.

Finally, add this pretty plausible principle:

3. All the parts of a physical entity are physical.

Here is an interesting consequence of (1)–(3):

4. If there is any non-physical entity, any entity that has a cause has a cause that is not a physical entity.

For if w is an entity that has a cause x, and y is any non-physical entity, by (2) there is a z that x and y are both parts of. By (3), z is not physical. And by (1), z causes w.

In particular, given (1)–(3) and the obvious fact that some physical thing has a cause, we have an argument from causal closure (the thesis that no physical entity has a non-physical cause) to full-strength physicalism (the thesis that all entities are physical). Whatever we think of causal closure and physicalism, however, it does not seem that causal closure should entail full-strength physicalism.

Here is another curious line of thought. Strengthen (2) to another consequence of mereological universalism:

5. The cosmos exists, i.e., there is an entity c such that every entity is a part of c.

Then (1) and (5) yield the following holistic thesis:

6. Every item that has a cause is caused by the cosmos.

That sounds quite implausible.

We could take the above lines of thought to refute (1). But (1) sounds pretty plausible. A different move is to take the above lines of thought to refute (2) and (5), and thereby mereological universalism.

All in all, I suspect that (1) fits best with a view on which composition is quite limited.

Saving a Newtonian intuition

Here is a Newtonian intuition:

1. Space and time themselves are unaffected by the activities of spatiotemporal beings.

General Relativity seems to upend (1). If I move my hand, that changes the geometry of spacetime in the vicinity of my hand, since gravity is explained by the geometry of spacetime and my hand has gravity.

It’s occurred to me this morning that a branching spacetime framework can restore the Newtonian intuition of the invariance of space. Suppose we think of ourselves as inhabiting a branching spacetime, with the laws of nature being such as to require all the substances to travel together (cf. the traveling forms interpretation of quantum mechanics). Then we can take this branching spacetime to have a fixed geometry, but when I move my hand, I bring it about that we all (i.e., all spatiotemporal substances now existing) move up to a branch with one geometry rather than up to a branch with a different geometry.

On this picture, the branching spacetime we inhabit is largely empty, but one lonely red line is filled with substances. Instead of us shaping spacetime, we travel in it.

I don’t know if (1) is worth saving, though.