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



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Introduction

The mental is normative. Or so a number of philosophers say, at least. For various reasons, those who say it often make a point of avoiding putting the matter in overly metaphysical terms. So for instance Donald Davidson, in setting up a defense of the mental’s normative status, writes that “the mental is not an ontological but a conceptual category . . . To say of an event, for example an intentional action, that it is mental is simply to say that we can describe it in a certain vocabulary.”1 The mental’s normative-based irreducibility to the physical, then, is a mere conceptual irreducibility, for Davidson. It is the irreducibility of normative mental concepts to non-normative physical concepts.2

In a similar vein Robert Brandom provides part of the historical context of his own normative view of mind when he writes that the

emphasis on the normative significance of attributions of intentionally contentful states marks a decisive difference between Kantian and Cartesian ways of conceiving cognition and action . . . Where Descartes puts forward a descriptive conception of intentionality, Kant puts forward a normative or prescriptive one – what matters is being the subject not of properties of a certain kind but of proprieties of a certain kind.3


It goes without saying, no doubt, that the Kantian conception is the deeper of the two by Brandom’s lights.

One of the central claims defended in this work is that the proprieties Brandom mentions just are properties, and properties distinct from any which are not proprieties. Thus, a new Cartesian/Kantian synthesis is offered. Or, at least, what is offered is a view according to which the mental’s normative status sets it apart metaphysically – and not merely conceptually – from the physical. This normative status renders mental properties irreducible to physical properties, though not in a way that is incompatible with physicalism. Inspired in no small part by Davidson’s classic paper “Mental Events,” my normativism about the mental aspires to be a novel form of nonreductive physicalism.

A consequence of my metaphysical focus is that the metaphysics of normativity, and of the relation between the normative and the non-normative, comes to play an absolutely central role in the discussion. If the mental’s normative status is supposed to be what guarantees its irreducibility to the physical, then presumably the normative itself must be irreducible to the physical, or more generally to the non-normative. In this work I argue that this is indeed the case. In doing so, I end up occupying a metaphysical view of the normative that is importantly like G. E. Moore’s antireductionism in metaethics. There are occasional references to Moore in Davidson’s own defense of antireductionism about the mental, and in the works of certain philosophers sympathetic to Davidson, like John McDowell.4 The metaphysical focus of the present work leads to an expanded role for Moore, though, or at least for a broadly Moorean sort of view.

This appropriation of Moore would appear to create tension for my claim that the view being defended is physicalistic. After all, Moore himself is a non-naturalist about normativity. It is in the attempt to alleviate this apparent tension that I turn to the causal exclusion problem facing nonreductive physicalists. If my normativity-based antireductionism about the mental can be reconciled with a physicalistically acceptable account of mental causation, then that would seem to undermine the charge that my view is not sufficiently physicalistic. And this in turn would eliminate one of the most serious barriers to embracing an antireductionist view of normativity and (thus) the mental. Even aside from wanting to have an acceptable account of mental causation for its own sake, then, I turn to the causal exclusion problem partly for the purpose of earning a physicalist credential for my antireductionist view.

Given the themes set out, there are bound to be important similarities between the position defended in this work and Davidson’s. There are also important differences, however, some of which are explained in Chapter 1. One of the primary differences is that I am highly suspicious of the sort of causal argument for physicalism which is at the center of “Mental Events.” I contend that though the causal argument is sound, there are reasons to think that it is not cogent – that is, that the argument cannot help one come to learn (for the first time) the truth of physicalism. This is because the most plausible way of defending the causal argument ends up committing its defenders to an epistemically problematic form of non-causal overdetermination. We ought to be physicalists, but probably not on the basis of the reasoning offered by the causal argument.

In Chapter 2 I turn to the claim defended by Davidson and others that the mental realm is governed by constitutive principles of rationality. What does this constitutive rationality thesis mean exactly? I borrow the machinery of Ramsification to try to formulate the thesis in as clear terms as possible. Briefly stated, the idea is that this constitutive rationality thesis is true just in case the theory that specifies the essences of mental states (the theory being Ramsified) includes normative clauses. The thesis so understood does not outright contradict causal functionalism, but a kind of tension with causal functionalism is set up at this point.

I then turn in Chapter 3 to defending the constitutive rationality thesis just formulated. I develop two distinct arguments, one from essential causal powers and one from counterpossibles. The argument from essential causal powers says that while belief actually has many different sorts of causal powers, the only powers that are essential to it are its rational powers – that is, its powers whose exercise are to the rational credit of believers. If this is correct it is something that calls out for explanation, and only the constitutive rationality thesis is able to explain it adequately. The argument from counterpossibles involves assessing what would follow if (per impossibile) normative eliminativism were true. One thing that would follow, I claim, is that there would be no beliefs. Defending this claim requires establishing the conceivability of belief zombies – that is, physical duplicates of us who lack beliefs. In attempting to do this, I build on Jaegwon Kim’s critique of Quine’s naturalized epistemology.

With the close of Chapter 3 I take myself to have established the truth of the constitutive rationality thesis. I then begin chapter 4 by arguing that it follows from the thesis that belief properties themselves are normative. Now, this normative status does not by itself entail that belief properties are irreducible. What is needed for this conclusion is the further premise that normative properties in general are irreducible. The remainder of the chapter is spent building toward this further premise. In arguing that normative properties are irreducible, I draw on the parallels that philosophers including Frank Jackson and others have noted between certain views of normativity and certain views of phenomenal consciousness. While these parallels are interesting for their own sake, the primary reason for appealing to them is that they genuinely help clarify the views of normativity in question, since the metaphysical differences between the relevant views of phenomenal consciousness have been worked out to some extent. Given this framework, I observe that my antireductionism about normativity is like David Chalmers’ antireductionism about phenomenal consciousness in important respects.

There are also important differences between the two views, however. In particular, antireductionism about normativity and thus belief is compatible with at least a moderate form of physicalism, or so I suggest in Chapter 5. I begin by noting that normative antireductionism is compatible with the metaphysical (as opposed to mere nomological) supervenience of everything on the physical. The question then is whether such supervenience is sufficient for physicalism, as is often thought. Terence Horgan has argued that it is not. Horgan claims that physicalism requires not just supervenience, but superdupervenience. I concede that my antireductionist view is incompatible with superdupervenience. Still, a further physicalist credential for my view would be secured if I could show that my normativity-based antireductionism about belief properties is compatible with a physicalistically acceptable account of mental causation. This would distinguish my view from others that are incompatible with superdupervenience, like standard emergentist views, which seem to require physicalistically objectionable forms of downward causation. I thus turn to the causal exclusion problem.

I set out the exclusion problem as a demonstration that six theses, each of which is independently plausible, are jointly inconsistent. One of the theses must be rejected then. Out of the six, only three are real options for rejection, given physicalism. Chapter 6 is devoted to examining different reductionist accounts, which reject the thesis that mental properties are irreducible to physical properties. What the various reductionist views in question have in common is that they all deny the existence of properties that are both natural and multiply realizable.

In Chapter 7, I try to show what is problematic about such a denial. I develop an empirical, inference to the best explanation (IBE) argument against reductionism. The key idea is that antireductionists are better positioned to explain the truth of certain empirically discovered generalizations than are reductionists. The IBE argument is heavily influenced by Jerry Fodor’s argument against reductionism from special science laws, though there may be certain differences. Also, I show that the generalization of the causal exclusion problem leads to difficulties for reductionists, not because it is especially absurd to think that various special science properties are epiphenomenal, but because the generalization of the problem deepens the pool of potential empirical evidence available to the IBE argument.

In Chapter 8, I turn to consider those philosophers who respond to the causal exclusion argument by embracing pervasive causal overdetermination. I claim that Stephen Yablo’s account of mental causation can be understood in this way, at least insofar as it relies on his notion of proportionality. I attempt to show that there are possible counterexamples to Yablo’s account. Moreover, I attempt to show that Yablo’s core problem is not the details of his account, or his reliance on counterfactuals, but rather the underlying thought that the causal efficacy of mental properties turns on how things go for the different physical realizers of those properties. This thought seems compelling only if we think of mental and physical phenomena as causally competing with one another. Once we reject this competition metaphor, there is no longer any reason to embrace the thought in question.

Finally in Chapter 9 I offer my own favored solution to the causal exclusion problem, which involves denying any causal competition between mental and physical properties. In order to set out my proposed solution in a clear way, I provisionally assume the truth of a Sydney Shoemakeresque view, which combines a reductive form of causal structuralism together with a subset view of realization. This allows us to see how mental and physical phenomena could have a shared structure, which kills the appearance of causal competition between them. Think of the property of being the striking of a match as compared to the property of being the striking of a dry match. The properties are distinct, and yet there is no causal competition between them. The Shoemakeresque view allows us to see how mental and physical properties could stand in a relevantly similar relation to one another. Having set out this account, I then consider how it fits with my own brand of antireductionism about the mental. I conclude that though my antireductionism requires us to reject elements of the Shoemakeresque view, it nevertheless fits with the account of mental causation itself. In this way, I take the causal exclusion problem for my antireductionistic normativist view to have been solved.




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