Hasker's argument from mental causation
B. The Argument from Mental Causation
The third argument, and a very significant one, is the argument from mental causation. Recall for a moment Lewis’s discussion of how rationally inferred beliefs must be caused:
But even if grounds do exist, what exactly have they got to do with the actual occurrence of the belief as a psychological event? If it is an event it must be caused. \It must in fact be simply one link in a causal chain which stretches back to the beginning and forward to the end of time. How could such a trifle as lack of logical grounds prevent the belief's occurrence or how could the existence of grounds promote it?
There seems to be only one possible answer. We must say that just as one way in which a mental event causes a subsequent mental event is by Association (when I think of parsnips I think of my first school), so another way in which it can cause it, is simply by being a ground for it. For then being a cause and being a proof would coincide.But this, as it stands, is clearly untrue. We know by experience that a thought does not necessarily cause all, or even any, of the thoughts which logically stand to it as Consequents to Ground. We should be in a pretty pickle
if we could never think 'This is glass' without drawing all the inferences which could be drawn. It is impossible to draw them all; quite often we draw none. We must therefore amend our suggested law. One thought can cause another not by being, but by being seen to be, a ground for it.
So besides the existence of facts to think about, and our capacity to perceive a self-evident rule that permits the inference (which we will get to when we talk about logical laws), we also must be able to arrange these facts to prove a conclusion, and it must be possible for new beliefs to be brought into existence by this kind of a process of reasoning. To those who, like Anscombe, are inclined to think that reasons-explanations are always non-causal in nature, I would like to ask how we are to understand words like “convince” or “persuade”? Presumably rational convincing and persuading is the goal of
argumentative discourse, but if reasons are in no sense causal in nature, this is impossible.
Suppose we were to answer Lewis’s questions “Even if grounds do exist, what have the got to do with the actual occurrence of belief as a psychological event” by saying "Nothing. Beliefs (if they exist at all given naturalism--of course this is denied by eliminativists) are strictly epiphenomenal. It seems to us that we hold beliefs for good reasons, but if we examine how these beliefs are produced and sustained, we find that reasons have nothing to do with it. We think they do, but this is just one more example of the 'user illusion.'” If we were to say that, it seems to me that the possibility of science as an operation would have to be called into question. As Jerry Fodor once put it:
"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.
Further, we have to look at just what is involved when we talk about causal transactions. Only some properties of an object are casually relevant to the production of the effect. For example, if I take the baseball that Luis Gonzalez hit to win the 2001 World Series for the Arizona Diamondbacks over the New York Yankees, and throw it at the window, it would break the window only in virtue of the force it applied to the window. It does not break the window in virtue of its having been the ball Gonzo hit against Mariano Rivera. When Lewis says “One thought can cause another not by being, but by being seen to be, a ground for it, obviously not only must one mental even cause another mental event, but it must do so in virtue of its propositional content, and in fact, in virtue of the kind of logical relationships between the relevant propositions.
There are a couple of arguments that have been developed to show that given the causal closure of the physical, rational inference is impossible. In William Hasker’s third chapter of The Emergent Self, entitled “Why the Physical Isn’t Closed,” Hasker uses a counterfactual argument to show that the kinds of counterfactuals involved in mental causation will turn out false if the physical is closed. Let’s just take what it is to be persuaded by the evidence for some claim. Let us say that Marcia believes that O. J. Simpson is guilty of murder on the basis of the blood evidence, along with other considerations. What this would have to mean is that if there were no evidence in favor of O. J.’s guilt, she wouldn’t think him guilty. If it turns out she was hardwired or sufficiently prejudiced to think of African-American former football stars as guilty of murder regardless of the state of the evidence, this would make your claim to believe on the basis of evidence false. So for someone to claim to believe that O. J. is guilty (or innocent) on the basis of evidence, the following conditionals must be true.
a) If strong evidence supporting O. J.’s guilt exists, then Marcia would believe that O. J. is guilty
b) If strong evidence supporting
If physicalism is true, then sufficient physical causes for one’s forming the belief that O. J. is guilty must exist if you are to believe that O. J. is guilty. Thus, if the physical conditions exist for you to form the belief that O. J. is guilty, then you will form that belief, and if they don’t you won’t. Yet, those physical conditions contain nothing about blood evidence or any other kind of evidence. After all, could be a similar world in which the evidence-thoughts do not occur, but the belief is formed anyway. As Hasker explains:
Following John Pollock, we assume that a counterfactual conditional is true if and only if the consequent is true in all those worlds minimally changed from the actual world in which the antecendent is true. Would a world minimally changed from the actual world in which she doesn’t see that her belief is supported by good reasons, be one in which she would not accept the belief? No doubt there are a number of different ways in which the world could be changed just enough to satisfy the antecedent of the conditional; in some of these she accepts the belief while in others she doesn’t. And there is no basis for saying that those in which she doesn’t accept it are less changed from the actual world in which she does, or vice versa.
I am assuming here, on the basis of my discussion of intentionality earlier, that mental states are not type-reducible to physical states. However, let us suppose that the mental state supervenes on the physical state. It is true, that, according to strong supervenience, the mental state must exist if the physical state does. Still, we can imagine the truths of supervenience being different from what they are, and if those truths of supervenience are different, the belief is formed in the absence of evidence. Further, if the universe is fundamentally physical, that means that the physical facts are the most fundamental facts in existence, more fundamental, surely, than the truths of supervenience.
Hasker considers the possibility that the truths of supervenience are metaphysically necessary truths. If the laws governing objects in the world are metaphysically necessary truths, then we can take a world of objects similar to this world, except with regard to the psychophysical connections that obtain in this world. Such a world would be a zombie-world, in which the basic properties of matter would be zombie-protons, zombie neutrons, zombie-electrons, zombie-quarks or zombie-strings. In such a world, again, the appropriate beliefs could be formed in the absence of the relevant evidence. The mental states are irrelevant to physical events, which have physical causes and only physical causes, according to materialism, and whatever mental states might exist, exist in virtue of the physical states.
On top of this, I should revert to what I said earlier, that the claim that given the physical, the mental necessarily supervenes seems to me just plain ungrounded. Given the physical, why does there have to be just these mental states? Why do there have to be intentional states at all. Appeal to supervenience in this context is just a mask for a lack of understanding, it seems to me.