Normativism and Mental Causation by Justin Thomas Tiehen, B. A. Dissertation

If the conclusions reached thus far are correct, they will have consequences for what the correct nonreductive account of mental causation will look like. In order to draw out these consequences, it will be helpful to return to Yablo’s own account and to counterfactuals like (Sob).

8.4.1 COUNTERFACTUALS AND CAUSAL REASONING

Whatever the exact relation between causation and counterfactuals may be, it is undeniable that we often do appeal to counterfactuals relevantly like (Sob) in sorting out causal matters. Imagine that a helicopter crash has taken place and that investigators have come up with two competing hypotheses as to why the crash occurred. The first hypothesis says that the crash was caused by high winds at the time of takeoff, while the second says it was caused by a malfunction in the tail rotor. In assessing which of these two competing hypotheses is correct, the following counterfactual, which has the same structure as (Cry), seems highly relevant: if the tail rotor had been replaced but the wind was blowing just as hard, the crash still would have occurred. The truth of this counterfactual would strongly suggest that the high winds hypothesis is correct and the malfunctioning tail rotor hypothesis is incorrect, while the falsity of this counterfactual would strongly suggest the opposite conclusions.

Yablo takes this sort of counterfactual reasoning, which seems so natural in cases like that involving the helicopter, and applies it to the causal exclusion problem. If I want to deny that this application is legitimate – which I do – then I need to point to some relevant difference between the helicopter case and the Gilmore cases we have been considering. Here is that relevant difference: in the helicopter case, we stipulated that the two hypotheses regarding the crash stand in competition with one another; but, I claim, there is no interesting sense in which mental properties or their instantiations stand in any sort of competition with physical properties or their instantiations.²⁷⁴

Let’s focus on the anxiety case, because it allows me to make my point most clearly. If one takes there to be a causal competition between the mental and the physical, then one will be forced to conclude that in the scenario I have described it is Gilmore’s P_H’ instantiation rather than his anxiety which wins that competition. After all, P_H’ necessitates heart rate acceleration, while anxiety is accompanied by heart rate acceleration only when it is realized by P_H’. But it is implausible that Gilmore’s anxiety does not cause his accelerated heart rate; thus, so much the worse for thinking of things in terms of causal competition.

8.4.2 CAUSES AND BACKGROUND CONDITIONS

The competition metaphor is hardly obligatory. Once we reject it, an alternative way of viewing the anxiety case makes itself available. Instead of taking Gilmore’s P_H’ instantiation to be causally competing with his anxiety, we might instead regard it as part of the background conditions which must obtain in order for anxiety to cause heart rate acceleration. Or, more aptly, we might think of the relation between Gilmore’s anxiety and his P_H’ instantiation as similar to – perhaps even exactly like – the relation between a cause which operates against a certain set of background conditions, and a broader cause which incorporates some of those background conditions within itself.

Suppose that I strike a match, causing it to light. The striking causes the lighting only because certain background conditions obtain – for instance, only because the match is dry. Now, the property of being the striking of a match differs from the property of being the striking of a dry match, since the former but not the latter is instantiated when a wet match is struck. Since that these two properties are distinct, we can apply the same sort of counterfactual reasoning to the present match case that we applied above to the helicopter case. In the present case, the counterfactual will go as follows: if the striking of the match had still occurred but had not been the striking of a dry match, the match still would have lit. Presumably this counterfactual is false: if the match had been wet when it was struck, it would not have lit. But then, if we apply the same sort of reasoning that we use in the helicopter case, we ought to conclude from the falsity of this match counterfactual that striking the match did not really cause it to light.

To draw this conclusion would be to badly misconceive the relation between causes and their background conditions, or more precisely between causes operating against certain background conditions and broader causes that incorporate those background conditions. There is no causal competition between the two properties we have isolated, and so the counterfactual reasoning which we employ in the helicopter case is completely out of place here.

I claim that we ought to view the anxiety case in at least roughly the same way. That is, we should no more take the falsity of (Heart) to show that Gilmore’s anxiety does not cause his heart rate to accelerate than we take the falsity of the match counterfactual to show that striking the match did not cause it to light. What the falsity of the match counterfactual shows is that striking a match can cause it to light only if certain further conditions obtain – specifically, only if the struck match is dry. Similarly, I claim, what the falsity of (Heart) shows is that anxiety can cause heart rate acceleration only if certain further conditions obtain – specifically, only if the anxiety is realized by a P_H’ state. A view along these lines yields what I regard as the intuitively correct results on the anxiety and pain cases we have considered in this chapter; Yablo’s proportionality view does not.

Before moving on, let me emphasize here that this background-conditions-approach to mental causation which I’m advocating, and which I will defend at greater length in Chapter 9, owes quite a bit to the first component of Yablo’s account of mental causation, his claim that the realization is relevantly like the determination relation. In his paper “Wide Causation” he writes the following.

Admittedly, the pain/ P_H : red/scarlet analogy isn’t perfect. This doesn’t concern me, unless the disanalogies are such as to make pain more causally competitive with P_H than colors are with their shades. As far as I can see, all that “Y is a determinate of X” needs to mean . . . is that Y necessitates X . . . because X is immanent in or included in Y. This is all it takes to kill the appearance of causal competition. To illustrate with a deliberately farfetched example, suppose that physical states turned out to be conjunctions with mental states as conjuncts. Conjunctions are not in any traditional sense determinates of their conjuncts, but so what? They do determine them in the sense just explained, and that is enough; P&Q can no more preempt P then scarlet can preempt redness.²⁷⁵
Let the property of being the striking of a match be P and let the property of being dry (or perhaps of being a dry match) be Q. Then the property of striking a dry match is the property P&Q. In further developing my background-conditions-approach to mental causation, I will in effect be pursuing a fairly literally minded defense of the “deliberately farfetched” idea Yablo describes here.

8.4.3 REALIZATION-SENSITIVE CAUSAL POWERS

Again, I take it that natural properties bestow the same causal powers on their various instantiations. How can this view be reconciled with the claims I have advanced in this chapter? If anxiety causes heart rate acceleration only when it is realized by a P_H’ instantiation, and not when it is otherwise physically realized, doesn’t it follow that different anxiety instantiations are bestowed with different causal powers? If so, then it seems to follow that anxiety is not a natural property.

The way I want to try to block the entailment here is by introducing what I will be calling realization-sensitive causal powers. Many of the causal powers that natural properties bestow are conditional in nature, meaning that they can be exercised only when certain specified conditions obtain. To take Shoemaker’s example, the property of being knife-shaped bestows on its instantiations the power to cut wood, provided that the knife-shaped thing is made of steel.²⁷⁶

In the anxiety case, my suggestion is that we ought to view anxiety as a natural property that contains within its causal profile the conditional power to cause heart rate acceleration, provided that the anxiety is realized by a P_H’ instantiation. On my view we should take this conditional power to be bestowed on all anxiety instantiations, not just those which are realized by P_H’. What is special about P_H’ realized anxieties is that only they are able to exercise this causal power. Compare the property of being knife-shaped on this point. According to Shoemaker, this property bestows on all its instantiations the power to cut wood, provided that the knife-shaped thing is made of steel. If the thing is instead made of plastic, this power to cut will not be exercised. Plastic knives cannot cut wood.

Realization-sensitive causal powers as I am envisioning them would appear to violate Kim’s causal inheritance principle, introduced back in subsection 7.3.2. Recall, Kim’s principle say that for any multiply realizable property MR, if an MR instantiation is realized by a P_i instantiation, then the causal powers possessed by that MR instantiation will be identical to those possessed by that P_i instantiation. Now consider what the present account entails for an instantiation of anxiety that is realized by an instantiation of P_M’, say. The anxiety in question possesses the power to cause heart rate acceleration if it is realized by P_H’, but (presumably) this is not a causal power that the P_M’ instantiation can possess. Thus, the mental property instantiation possesses causal powers over and above those of its physical realizer, violating Kim’s principle. Still, it is not as though these further causal powers are completely physically ungrounded, they are not “sheer magic,” as Kim puts it. For, the additional causal power in question is grounded in the fact that an alternative physical realizer of anxiety, P_H’, possesses this causal power. Given this physical grounding I deny that the present view is physicalistically objectionable, despite its violation of Kim’s principle.

One way to reinforce the compatibility with physicalism is as follows. Shifting from anxiety back to pain, imagine that I experience a pain which is realized by firing C-fibers. Now, suppose that my pain has all the causal powers that the firing C-fibers instantiation has. Thus far, we have not supposed anything that violates physicalism or Kim’s principle. Next, suppose that as I experience my pain, I undergo neurosurgery which involves removing my C-fibers and instantaneously replacing them with silicon chips that are also capable of realizing pain. I am conscious throughout the surgery, and recognize no change in my pain throughout the entire ordeal. Question: as physicalists, are we forced to say that my pain prior to surgery is numerically distinct from my pain after it? I do not think that we are.

Perhaps just as the Ship of Theseus persists even while all of its original wooden planks are replaced, pains can persist even while their underlying physical realizers are replaced.²⁷⁷ Of course, there are questions that can be raised about how this sort of constitution without identity works. It may be that the notion is deeply metaphysically problematic. All that the present argument requires, though, is that it not be physicalistically problematic. And it seems clear that it is not. After all, it does not appear to be specifically physicalistically objectionable to hold that the Ship of Theseus survives the replacement of its planks.

Suppose for the sake of argument, then, that my (token) pain survives the surgery. Now, what happens to all of its original causal power? If my pain’s causal powers are essential to it – and it seems plausible that in general an event’s causal powers are essential to it – it then follows that these causal powers will persist after the surgery. But then, if firing C-fibers has any causal powers that silicon chips lack – as it surely will (like the power to cause a firing C-fiber detector to beep) – it follows that after the surgery, my pain will have causal powers which its (new) physical realizer lacks, in violation of Kim’s causal inheritance principle. Again though, none of the premises that have led us to this conclusion seem obviously physicalistically objectionable. Thus, I deny that physicalism demands the truth of Kim’s causal inheritance principle: physicalism can be true even if mental events have (many) more causal powers than the physical events that realize them do, provided that those additional causal powers are realization-sensitive.

This way of rejecting the causal inheritance principle can be usefully contrasted with the way in which Shoemaker rejects it.²⁷⁸ According to Shoemaker’s account, which we will examine at greater length in Chapter 9, the causal profile of a mental property M is a (not necessarily proper) subset of the intersection of the causal profiles of M’s physical realizers. If, say, M is multiply realized by P and P*, and P’s causal profile is {a, b, c} while P*’s causal profile is {a, b, d}, then M’s causal profile will be a (not necessarily proper) subset of {a, b}. This view entails that each mental property instantiation will have fewer causal powers than the physical property instantiation that realizes it. In other words, Shoemaker rejects the causal inheritance principle by going in the opposite direction of the way I go. This is how he seeks to maintain that mental properties are natural.²⁷⁹

I believe that the same sorts of considerations that speak against proportionality speak against Shoemaker on the present point. If Shoemaker’s view is right, then Gilmore’s anxiety does not cause his heart rate acceleration and – to focus on my stronger case – his pain does not cause his sobbing. For, neither of these causal powers will belong to the intersection of the causal profiles of the relevant physical realizers in our example. These causal powers are more like c or d in the preceding paragraph than they are like a or b – they are possessed by some physical realizers, but not all. For the reasons already set out in this chapter, I think that this consequence of Shoemaker’s view is implausible.

8.4.4 PUTNAM’S PEG

In closing, let me make a kind of concession to Yablo’s proportionality, and to those accounts of mental causation that have been inspired by it. I take it that many of the causal powers of mental properties are realization-insensitive, at least more or less. If this were not so, then differently physically realized instantiations of any given mental property would behave completely differently. Presumably, though, this is now how things go.

In fact, Chapter 7’s argument against reductionism depends on things not going this way. If all causal powers were realization-sensitive, then there would be no C-generalizations of the sort that the IBE argument against reductionism requires. More generally, there would be no “higher level patterns” of the sort that so many nonreductive physicalists appeal to in making their case against reductionism. One of the best known illustrations of this idea of higher level patterns is provided by Putnam’s example of the peg that is able to pass through a square hole but not through a round one.²⁸⁰

According to Putnam, an explanation of why the peg is able to pass through one hole but not the other which cites the specific microphysical properties instantiated by the peg is a worse explanation (perhaps it is even no explanation at all) than one that abstracts away from this level of detail and instead cites the higher level geometrical properties possessed by the peg. And this is because the higher level explanation is more general, meaning that it would continue to hold even if the peg instantiated different microphysical properties while continuing to possess the higher level geometrical properties in question. Yablo’s account of proportionality fits well with this thought.

Now, I readily accept that higher level patterns of the sort can be used to construct a case against reductionism. In addition, I am willing to grant that explanations that are more general in the present sense – and more specifically, explanations that cite proportional causes, in Yablo’s sense – are better than explanations that do not. What I deny is that this is what matters most to us when it comes to mental causation. When Gilmore’s anxiety causes his heart rate to accelerate, this causal relation does not fit into a higher level pattern of the sort Putnam describes. Nevertheless, provided that the anxiety still causes the heart rate acceleration – as I have argued is the case – what matters to us most about mental causation will be in place, regardless of whether or not the causal interaction fits into a higher level pattern of the sort Putnam describes.

In one of the most widely quoted passages in all of the mental causation literature, Fodor writes,

if it isn’t literally true that my wanting is causally responsible for my reaching, and my itching is causally responsible for my scratching, and my believing is causally responsible for my saying . . . , if none of that is literally true, then practically everything I believe about anything is false and it’s the end of the world.²⁸¹