Agent causation

I have long identified as having an agent-causal theory of free will. But I have just realized that my Aristotelian take on agent causation is far enough from the most common agent-causal theories—those of Clare and O’Connor—that it may be misleading to talk of myself as accepting an agent-causal theory of free will.

Standard agent-causal theories distinguish between agent causation and event causation as two distinct and real things in the world. For instance, they hold that I agent cause my writing of this post but there is an event causal relation between my being in this armchair and the cushion being squished. Agent causation has the agent as the cause and event causation has an event as the cause. But I think in both cases the cause is the same: it is a substance, namely myself. I cause the writing of this post and I cause the cushion to be squashed. On the standard view on which agent causation is distinguished solely by the fact that the cause is the agent, both are cases of agent causation. But that would be misleading to say.

So, if we take seriously the Aristotelian account of causation as substance causation, we shouldn’t distinguish agent causation from other kinds of causation by whether the cause is an agent or something else. But we can still make the distinction. My writing this post is an actualization of a power of my will (or my practical rationality, if you prefer). My squashing the cushion is an actualization of the power of my weight. Agent causation is distinguished from other kinds of causation not by what does the causing, but how it does the causing. In agent causation, the substance causes by actualizing its will (and any substance with a will is an agent). In other kinds of causation, the substance causes by actualizing a different power.

So, I think the fundamental relation underlying causation is actually at least ternary: agent X causes event E by actualizing power P.

This neatly integrates agent causation with reasons causation. There are more and less proximate powers. I now have a nearly proximate power to speak Polish (some motivation might be needed to make it proximate). When I was an infant, I had a remote power to speak Polish, by having a nearly proximate power to learn Polish. When the power P in the causal relation is specified as the maximally proximate power, in the agential case, it is a maximally proximate power of the will. And a maximally proximate powers of the will are tied to reasons: it is only by having a reason to do something that I am able to will it (one wills under the guise of the good). So, my reasons for action supervene on the maximally proximate power for action. Thus, the ternary description of agent causation neatly includes the reasons.

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.