Substance causation, agent causation and time

Aristotelians about causation think all causation is substance causation. Events are causes only derivatively. What does the real causing are substances. This should make Aristotelians very sympathetic to the use of agent causation in the theory of free will. And insofar as the theory of agent causation is just that the agent is the cause of free actions, the Aristotelian who believes that we are substances[note 1] is surely going to agree that we are the causes of our free actions, and we are both agents and substances, so the agent is the cause of her free actions.

So far so good. But there is more to agent causation in regard to free will. Typically, agent causalists invoke agent causation to solve problems such as the randomness problem for libertarians. Agent causation is what makes an action be genuinely one's own action rather than a random blip. But the Aristotelian's embrace of substance causation is too broad. For not only does the Aristotelian think that her free actions are caused by her, she also thinks her non-free actions are caused by her, and even things like the circulation of the blood, which isn't an action at all, are caused by her. Moreover, since she is an agent, she thus thinks all of these things are caused by an agent. But if agent causation metaphysically lumps free actions with non-free ones, and doesn't distinguish them metaphysically from the circulation of the blood, then agent causation can't do the job it's designed for. The Aristotelian believes in agent causation, of course, and may do so with good metaphysical reason, but this agent causation cannot be used to solve the problems that the free will theorists want it to solve.

This line of thought might lead some Aristotelians about causation to accept a version of Cartesian dualism on which we are souls. For then one might hold, contrary to Aristotle, that only our free actions are caused by us and that the circulation of the blood and so on is not caused by us, because we are immaterial beings whose only direct effects are in whatever the equivalent of the pineal gland on this theory will be. This is not in the Aristotelian spirit, though, and it leads to unhappy ethical conclusions (bodies as akin to property).

I think there is something else one should say here. One shouldn't say that agent causation just is causation by an agent. Rather, agent causation is causation by an agent qua agent. You cause your free actions qua agent and you circulate your blood qua mammal, though of course you are both agent and mammal. It is a bit odd to say that you don't perform your non-free actions qua agent, though. After all, how can there be an action without an agent? Aren't all actions, free or not, the actions of an agent qua agent? Maybe. But maybe the distinction is still of some help, for maybe the kinds of mere randomness we want to rule out with the distinction isn't an action at all when looked at more closely.

There is another issue around here. There needs to be more to substance causation than the simple structure substance x causes event E. For paradigmatic substances persist over a long time, but many of their effects happen only at particular times in their existence. And there is an explanation of why the substance causes an effect at one time or another. For instance, I caused oatmeal to be assimilated to me earlier to day because I was hungry. The explanation includes not just the substance, but a state of a substance (and maybe other substances—but that's for another day). I caused the assimilation of my breakfast not only qua agent, but qua hungry agent. Likewise, I circulate the blood not just qua mammal, but qua mammal with a brain stem that sends such-and-such electrical signals to the heart.

Apart from considerations of free will, then, Aristotelians should say that the structure of substance causation is something like: substance x qua in state S causes event E. If we have an Aristotelian constituent ontology, then the state will be a mode (an essence, a necessary accident or a contingent accident) of the substance, and the causation relation will be a ternary relation between the substance, the mode and the event.

But now that we have all of this detail in place, we can go back and ask whether we still get benefits of an agent causal theory in regard to free will. That's not so clear. For instance, when I qua hungry agent caused my breakfast to be assimilated to me, the work distinguishing this from non-actions like circulation is being done by my state of hungry agency. It is because this state is involved in the causation—and not just involved, but involved in the right way (my being a hungry agent could cause me to grow a tail if I was rigged the wrong way)—that I am acting. But event causalists can say something exactly parallel. What distinguishes my eating the breakfast from my circulating the blood is that the former is caused by the event of my being a hungry agent qua my being a hungry agent.

So I do not know that Aristotelian agent causalists can claim to do better than event causalists. In fact, for certain ends they might well want to join cause with the event causalists.

Two legs, four legs and the Incarnation

In this picture from 30 Rock's "Brooklyn Without Limits" episode, Kenneth has only two legs and yet Kenneth has four legs. This sounds like a contradiction, but of course it is not--we can see that it's not.

How shall we resolve the contradiction? Perhaps: Kenneth has two human legs and four table legs. But that suggests that Kenneth has six legs, and that doesn't seem right to say. Maybe we can say that his human legs are also table legs, so he has only four legs: two of them doing double-duty for table legs and human legs, and two of them doing double-duty for table legs and human arms. Maybe. But even the statement "Kenneth has four legs" seems wrong or at least misleading without qualification.

Much better to qualify with a qua: Kenneth qua human has only two legs. Kenneth qua table has four legs.

This should remind us of one of the standard solutions to apparently contradictory talk of Christ incarnate. Christ is eternal. Christ is conceived in time. Christ has boundless knowledge. Christ's knowledge is bounded. And so on. The solution is to say things like: Christ qua God is eternal and has boundless knowledge. Christ qua human is conceived in time and has bounded knowledge--and has two legs.

The naturalness of qua talk in the case of Kenneth should make us less suspicious of the incarnational case.

The incarnation and adverbial ontology

Christ is God and Christ is a human. God is unchanging and humans are changing. God is omnipresent and humans are spatiotemporally delimited. God is all powerful and the power of humans is limited. All praise be to Christ on this Christmas day!

Yet such theological claims appear to lead to contradiction: is Christ unchanging or change? is he limited or unlimited? Since we have excellent reason to think the claims are all true, we have excellent reason to think the claims are not contradictory. A traditional way to resolve the apparent contradiction is to introduce a qua or as qualifier:

1. Christ is unchanging, omnipresent and omnipotent as God, but as human he changes, and is limited in presence and power.

Such answers do work logically speaking, but it would be good to have a little bit more to say about what the "as" does.

I want to suggest something that may not be original[note 1] but that I found enlightening. Start with the observation that there is no contradiction at all in this sentence:

2. Sam is quick as a reader and slow as a runner.

And there is an obvious and easy way to understand (2) that removes all appearance of contradiction:

3. Sam reads quickly and runs slowly.

No contradiction results from contradictory adverbs being attached to different predicates. From Sam reading quickly we can deduce that Sam does something quickly, but that does not contradict his doing something else slowly.

Now we can make the same move in regard to (1). We will need two base predicates which are then adverbially modified. The ones that come to mind are "is God" and "is human". Then (1) becomes:

4. Christ is God unchangingly, omnipresently and omnipotently, but he is human changingly and limitedly in presence and power.

So far that's just words. But now make it into ontology. The ontology takes a cue from Spinoza's nesting of modes. (Other philosophers have nested modes, but I think it is only in Spinoza that the nesting is really central.) When Sam reads quickly, there is Sam, who reads, and Sam's reading, which is quick. If Sam reads excessively quickly, there is Sam, who reads, and Sam's reading, which is quick, and the quickness of Sam's reading, which is excessive. All of these, other than Sam himself, are modes (Spinoza wrongly thinks Sam is a mode, too). We can now talk of a mode being directly or indirectly a mode of something. Thus, the quickness of Sam's reading is directly a mode of Sam's reading and indirectly a mode of Sam. The excessiveness of Sam's quickness of reading is directly a mode of Sam's quickness of reading and indirectly a mode of Sam's reading as well as of Sam.

Next theorize that a mode m is an essence of an individual x if and only if m is directly a mode of x. This could simply be a necessary "if and only if" or, more ambitiously, it could be an account of what it is to be an essence, essences being nothing but direct modes. Observe that this is a non-modal account of essence—here we are talking of essence in the ancient and medieval sense, not in the modern modal sense (such a distinction was pointed out by Fine, but the best account in print is by Michael Gorman).

Thus all our accidental modes are indirectly modes of us, through our essence. My present typing of this post is a mode of my humanity: I am human typingly. And Christ, unlike us, has (at least[note 2]) two essences: humanity and divinity. Thus any mode of his is one of his essences or is a mode of one of his essences. (Sometimes our words will be ambiguous. Thus when we say that "Christ is wise", that is ambiguous whether he is divine in a wise manner or is human in a wise manner or both.)

This account makes it plausible that analogy will be a central concept. Adverbs apply analogically across predicates. The "quickly" in "Sarah runs quickly" and "Sarah thinks quickly" is to be understood analogically. In general, I suspect cross-essence predications are to be understood analogically. That is a Thomistic aspect in the theory.

Another Aristotelian aspect is that we can make sense of "necessary accidents". Thus, Aristotle thinks it is an accident of a human that the human have a capacity for laughter, but he also thinks this is a necessary accident—every human necessarily has a capacity for laughter. It is insufficient for a mode to be an essence that the mode is necessary: it must be directly a mode of the individual. But just as it is indirectly a mode of me that I be laughing—I am human laughingly when I laugh (which differs from, say, being an alien or angel laughingly)—it indirectly but necessarily a mode of me that I have a capacity for laughter—I am a human with a capacity for laughter ("with..." is one of the many ways of indicating adverbial modifiers).

There is a serious theological difficulty. Does not the account contradict divine simplicity? After all, does not (4) posit a mode of God, namely divinity, and modes of a mode of God, namely omnipresence of divinity, omnipotence of divinity and unchangingness of divinity? Yes, but that only contradicts divine simplicity if these modes are all distinct. But they aren't distinct. Divinity, omnipresence of divinity and all the others are all just God. Thus God is his own mode in this technical vocabulary. But since predication of God is analogical, what this means it that God is related to himself in a way analogical to our relationship to our modes. (Compare: the person who loves herself is related to herself in a way analogical to the way someone who loves another is related to that other.) It's important not to take "mode" to mean "accident", but that was already something necessary from the fact that essences are modes.

Of course, this is not a complete account of divine simplicity yet. Something needs to be said about apparently contingent modes of God, such as creating Adam. (I think claims like "God creates Adam" should not be taken as predicating a mode of God. Why not, with the medievals, take the claim as predicating a mode of Adam? Or as predicating being creator of all contingent beings of God and contigency of Adam?)

This reconciliation with divine simplicity does, however, mean that I cannot simply define a substance as something that isn't a mode. For God on this reconciliation is a substance and a mode. (And that is Thomistic, too, though the vocabulary of "mode" is not. God is both substance and that substance's pure act.) We might define a substance as something that isn't a mode of anything else. Or we might say that x is a substance if and only if the proposition that x exists has a truthmaker which is x and has no other truthmaker.

Finally, I leave it as an exercise to the reader to extend my "metaphysically Aristotelian quantification" to this context. At the same time, some of my cross-level uses of "is" in this post will need some charitable analogical reading.