Coarse-Grained versus Fine-Grained Accounts
First, a note about some of the above phrasing. I have purposefully spoken only of events involving properties. I adopt this loose form of speech because I do not want to imply that events have properties.3 I find the idea that properties could characterise events to be confused. Properties only characterise objects, or, in other words, substances. It might be the case, as Kim holds, that events just are property-instantiations—that is, that an event is the instantiation of a property by a substance (at a time) (Kim 1993a).4 In that case events involve properties. But the claim that events are property-instantiations is not to be confused with the claim that events instantiate properties. Properties are not instantiated by events—they are instantiated by substances. It is the stone that is hard and the vase that is fragile. Property-instantiations, the stone-instantiating-hardness or the vase- instantiating-fragility, do not instantiate properties and any suggestion to the contrary seems to be guilty of a category mistake. (The claim that property-instantiations do not instantiate properties is one that I shall return to and defend in section 4, which discusses the third qua problem.)
Given these considerations, we can now clarify what it means for an event to “involve” a property and how this differs from the sense in which substances “involve” properties. Substances involve properties because they have properties. Events involve properties because an event just is a substance instantiating a property or, given less fine-grained accounts of events, a substance instantiating several properties or some complex of substances instantiating various properties.
Let us now turn to the distinction between “fine-grained” and “coarsegrained” entities. To accept that events are Kimean—that is, that an event is the instantiation of a property by a substance—is to advance a fine-grained account of events. This is because each Kimean event involves only one property. (This is, of course, not to suggest that, if Kimean events are the causal relata, the complete cause of an event will therefore only involve one property. The complete cause of an event in most cases will be a complex of Kimean events.) Alternatively, one might advance an account of the nature of an event according to which events are qualitatively dense—each event involves several properties as opposed to just one. (For example, given a coarse-grained account of events, one might hold that Kate’s party is an event and that it is an event which involves the property of being on the 27th May, the property of having thirty guests, etc.).5 But in light of what has just been said—namely, that it is substances that properties characterise—a far more obvious example of a coarse-grained entity is a substance.
Contrast the claim that Kimean events are causes with the claim that substances are. While Kim would claim that it is the stone instantiating the property of hardness that caused the vase to be cracked, those who accept that substances are causes would claim that it is the stone that caused the vase to be cracked. That is, it is the stone considered in all of its entirety that is the cause, not some cross-section of the stone, as Kim’s property- instantiation account of the causal relata suggests. (As an aside, note the claim here is that substances are always causes, not that substances are also always effects. In the above example, the suggestion that a substance is an effect is implausible, for the claim that the stone caused the vase makes no sense. Rather, a substance, the stone, caused the vase to be cracked, which is a property-instantiation, a Kimean event.)
Clearly, proponents of the claim that substances are causes would not wish to deny that substances enter into the causal relationships that they do because of the properties that characterise them. As Lowe, a substance causation theorist, puts it, objects participate in causal relationships, and “an object participates in such relationships in different ways according to its different properties.” (Lowe 2006: 15) Nor would they wish to deny that (usually, if not always) when a substance participates in a given causal relationship, not all of its properties will be causally relevant to its participation in that causal relationship. The stone caused the vase to be cracked in virtue of its hardness, not, say, in virtue of its colour.
Are the causal relata coarse-grained or fine-grained entities? Where s i and s2 are substances and p1 and p2 are properties, a proponent of the claim that substances are causes will say that s1 causes s2’s instantiating p2 in virtue of s1 instantiating p1. A proponent of the claim that property-instantiations are causes will instead say that s1 instantiating p1 causes s2’s instantiating p2. The difference between these two positions is, I consider, simply one of approach. The first starts with the idea that substances are causes, the “engines” of causation, and then, due to the qualitative specificity of causation, “works in” by supplementing their claim with an “in virtue of” principle. The second starts by identifying the causally efficacious property and then ‘works out’ from this property, specifying what the instantiation of this property is an instantiation by.
However, for the purpose of the mental causation debate, assuming that causes are fine-grained entities removes a layer of unnecessary complication that this debate does not need. Say that one combines a substance monism with a property dualism—mental and physical properties are distinct properties of the body. If substances are causes, then this gives rise to the previously discussed qua problem. If mental substances are physical, and, hence, mental causes are physical, the combination of Closure and Causal Non-Overdetermination is consistent with mental causes having physical effects. But do mental causes ever have physical effects in virtue of their mental properties? Is there downward causal efficacy from mental properties?
If the causal relata are fine-grained entities, property-instantiations, there is no such qua problem. If the causal relata are property-instantiations, then causes do not have epiphenomenal properties. A mental cause is the instantiation of a mental property by a substance and a physical cause is the instantiation of a physical property by a substance. If a mental event is a cause in the physical domain, then the mental property that it is an instantiation of must be causally efficacious in the physical domain. Moreover, if events are property-instantiations, then one cannot combine an event monism with a property dualism. If a mental event is identical with a physical event, then the mental property that it is an instantiation of must be physical, because for two property-instantiations to be identical, they must be the instantiation of the same property. Consequently, if there are mental causes in the physical domain but these are identical with physical causes (and, hence, there is no downward causation) there is no further worry to be raised about whether “the mentalness” of the mental cause is in some sense causally redundant in the physical domain. The causal closure argument cannot plausibly be reasserted at some more fine-grained level.