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Reply to Juarrero

by Paul M. Pietroski e-mail

Dept. of Philosophy
Skinner Building
University of Maryland
College Park, MD 20742 - USA

 


I fear there has been a serious misunderstanding. It looks like Juarrero is accusing me of not considering my own view. But I did consider my own view. Sorting this out is going to require some quotation—and worse, self-quotation. Apologies in advance.

1. At one point, Juarrero writes:

But what about the possibility that constituted events might be causally distinct from their constituting events and yet not fusions of them? Pietroski never considers this possibility.

This came as a surprise. For on the view I urged, mental events are causes distinct from biochemical events. And I characterized neuralism--the thesis I was challenging--as a thesis that would be "true if mental events are fusions of biochemical events" (p.6). So it seems that I endorsed a thesis Juarrero thinks I ignored. Something has gone wrong.

My guess is that Juarrero got confused by part of my introductory chapter. There, I spent a little time saying why we can’t solve the relevant problems (concerning mental causation) just by stipulating that mental events are constituted (in some way or other) by biochemical events. For the real questions remain: are "constituted" mental events causes distinct from the "constituting" events, or not? If yes, hard questions about overdetermination present themselves; if not, hard questions about the apparent distinctiveness of mental causes present themselves. I characterized the kind of "event dualism" that interests me as an attempt to answer the first batch of hard questions in order to avoid having to answer the latter batch of hard questions. (See also the first page of my preface, the last page of the last chapter, many pages in between, the appendix, or the précis for this symposium.)

Nonetheless, Juarrero begins her remarks by saying that

From the outset, Pietroski warns that he will be (sic) not distinguish between the following two claims: (1) that "mental events are identical with certain neural events; and (2) that mental events are constituted by neural events, where `constitute’ is understood so that constituted events are not causes distinct from their constituting events" (p. 6).

Now just before the bit she quotes, I had granted that neuralism "has many attractions," not least of which is that "if mental causes are neural causes, there is nothing puzzling in the fact that certain bodily motions have mental and neural causes." And I construed neuralism "in terms of the puzzle it is supposed to dispel" (p.6). The puzzle in question concerns how bodily motions can have both mental and biochemical causes. So I went on to say that "for the most part", I would not distinguish constitution from identity. This is not because I don’t think one can make a reasonable distinction here. But for the purposes at hand, it would be a distinction without a difference. Event dualists hold that mental causes of bodily motions are causes distinct from any biochemical causes of those bodily motions. That is, even dualists deny both of the following claims: (i) mental events are literally identical with (fusions of) biochemical events; and (ii) while mental events are not literally identical with (fusions of) biochemical events, mental events are constituted by biochemical events in a way that keeps mental events from being causes distinct from the events that constitute them. Given the kinds of considerations I was considering, (i) and (ii) are more or less on a par; so I proposed not to fuss about the difference, leaving it to individual neuralists to decide which version of neuralism is better, all things considered.

Juarrero, however, says that

Choosing to limit "constitute" in this restrictive sense has the following significant consequences: If global neural processes are mere "fusions" of their components – that is, causally indistinguishable from the micro neural events which so constitute them -- a fortiori, neuralism is true.

There is much to balk at here. First, I don’t see how the conditional follows. For it takes a premise—one that event dualists would surely challenge—to get from (a) the claim that global neural processes are fusions to (b) the claim that mental events are biochemical. Second, my aim was not to limit how the word ‘constitution’ is used. Indeed, as Juarrero notes, I immediately considered other possible uses of the term. My aim was to concede as much as I could to neuralists. Or put another way, I wanted to be clear at the outset that the kind of dualism under consideration (by me) is not merely the claim that mental events are not literally identical with any biochemical events. The claim under consideration was that mental events are causes distinct from any biochemical events—in a way that raises worries (about overdetermination, supervenience, and so on) that want dispelling. I also granted that fusions of events should not be regarded as causes distinct from the events they are fusions of, thereby providing a sufficient (but not necessary) condition for the truth of neuralism.

But I didn’t insist that human mental events are not in any sense constituted by biochemical events. On the contary, having offered a sufficient condition for the truth of a thesis I was rejecting, I added: "This is not to say that neuralism is true, if mental events are constituted by neural events in some way or other, with talk of mereological fusions being just one example of such a constitution relation….There is a sense in which supervenient entities are constituted by subvenient entities; and the mental supervenes on the nonmental. But as we shall see, it does not follow that mental events are not causes distinct from nonmental events. And if one defines ‘constitute’ so that constituted events cannot be causes distinct from their constituting events, then event dualists will deny that mental events are constituted (in this demanding sense) by nonmental events." This leaves room for the possibility that event dualists are wrong, even if mental causes turn out not to be literally identical with any biochemical causes. That is, as Juarrero notes, I allowed for the possibility of "an intermediately strong notion" of constitution, such that "constituted events are neither fusions of their constituting events nor causes distinct from their constituting events." But then I immediately added: "one cannot just assume that mental events bear some such metaphysical relation to events that satisfy untendentiously neural predicates. Absent an account of how constituted events can be causes that are not distinct from their constituting events, the main virtue of neuralism—viz., its simple explanation for why a bodily motion can have mental "and" neural causes—has been lost….In short, one makes choices about where to do the hard work on the mind-body problem. Historically and theoretically, the following choice has been particularly important: should one adopt the simple account of mental causation, and embrace the consequences of saying that each human mental event is (or at least fails to be distinct from) some biochemical event; or should one eschew these consequences, and defend another conception of mental causation?… Perhaps mental events are constituted by neural events in some such sense. But the word ‘constitution’ is not a talisman that protects against objections to both neuralism and dualism; it labels work that needs doing."

That was the context for the remarks Juarrero quotes. I was fairly brief (and introductory) about this, because I didn’t regard any of this as news. My intention was to offer a quick reminder of some familiar points, by way of saying at the outset that my kind of event dualism is substantive (i.e., in need of defense) even if you’re prepared to allow that mental events are not literally identical with (fusions of) biochemical events. The issue, again, was whether mental events are causes distinct from any constituting biochemical events—and thus whether we need to face (for example) overdetermination concerns that neuralism would let us avoid.

Juarrero thinks

In part, the source of the problem is the following: whereas Pietroski recognizes the load he places on the concept of "constitution,’ I believe that despite the comment that "therein lies the account of mental causation" he fails to recognize that implicit assumptions also weigh down the concept "distinct" -- and the relation between "constitution" and "distinctiveness."

But I didn’t put any load on the concept of "constitution." On the contrary, I said we wouldn’t get anywhere by insisting that only on a particular reading of ‘constitute’ are mental events constituted events. So it was distressing to read that

Throughout the book Pietroski appears to take a position that can be summarized in the slogan: "if X is constituted by Y, then X is ipso facto not distinct from Y."

I went out of my way to make room for a weak notion of constitution according to which even event dualists could grant that human mental events are constituted by biochemical events. But quite apart from my explicit rejection of the position Juarrero ascribes to me, her reading of my book presents hermeneutical puzzles. Why would someone go to the lengths I went to, with regard to addressing overdetermination concerns, if he thought mental events were not causes distinct from biochemical events? And why would he defend a substantive conception of causation, in conjunction with a nonstandard conception of supervenience, designed to allow for a certain kind of overdetermination (and a sense in which human mental events are constituted by biochemical events)?

In fact, the very quote Juarrero next cites makes the point:

"event dualists will say that mental causes fail to be biochemical causes, in any sense of `be’ that avoids the need for a substantive account of how an event can have mental causes and neural causes" (p.8).

Right. That was me saying what people like me owe. We have to answer some questions that neuralists can avoid—questions about how an event can have mental and neural causes (without engendering nasty overdetermination problems and coming to grief over supervenience). I said all this because I think you get a better sense of what a philosophical thesis amounts to if you look at which puzzles it helps dispel and which puzzles it makes harder (as opposed to just stating the thesis in terms of words like ‘constitution’, which tend to obscure at least as much as they clarify). So I must protest when Juarrero says that I am "fully aware" that my "project rests in large part on a specific construal of that term." She also says that

Throughout the book (cf p148), he repeatedly questions whether bodily motions can have "neural causes and distinct mental causes," hereby begging the question as to whether mental events can be constituted by neural ones while at the same time, qua mental, operating as distinct causal powers.

But how can I beg the question against myself? And while I think it’s reasonable to wonder whether whether bodily motions really can have both neural and distinct mental causes—that is, I think it’s reasonable to wonder whether the view I offered is right—I devoted more space to wondering how bodily motions could have both neural and distinct mental causes, on the tentative assumption that they do. And I spent a little time in the introduction trying to be clear about the kind of ‘how could it be’ question that I was going to be addressing.

2. Juarrero then complains that I don’t try to answer the question in Descartes’ own terms.

"Causation involving mental events [such as those engaging M and T] is not to be understood in terms of a mechanical model" (p.150). Whereas domino toppling is determined, he states, mental events are merely influenced (p.149) by outside events. Although Pietroski recognizes that this assertion requires that he spell out the difference between "determination" and "influence," he does not. Instead he abruptly changes the terminology in which the discussion is framed and begins to speak of the difference between explaining behavior in terms of "impersonal" causes versus explaining actions in terms of "rationalizing" causes.

Actually, I don’t grant that I have to spell out the relation between "determination" and "influence". That’s not my way of talking. (The quoted sentence was part of a characterization of a Cartesian view; the relevant section, 5.1.1, began with ‘According to Descartes…’) And while I think Descartes was onto something important, I think we do better to talk in terms of rationalizing/impersonal causes. (It wasn’t an abrupt change of terminology; it was a compare/contrast with Descartes, as explicitly noted in the introduction to chapter 5.) And it’s surely not surprising that I characterized the kind of dualism that interests me in a way that puts some distance between my views and Descartes’. The whole point was to explore a non-Cartesian dualism--hence, the discussion of Strawson on persons later in chapter 5.

Juarrero also complains that I don’t take the opposition seriously enough.

Neuralists such as Fodor, Pietroski recognizes, would counsel a different alternative: that some neural events are not mere neural events – that "some neural events are tryings and their mental causes" (p.152). Pietroski dismisses this proposal…

Dismiss? I repeatedly granted the virtues of the view--a view I used to hold, following many thinkers (from Smart and Armstrong to Davidson and Fodor) who I deeply admire--and wrote a book trying to sketch out an alternative. I did say that nobody believes neuralism on inductive grounds; and I’ll stick by that. We don’t yet have specific empirically defended identity (or constitution) claims. The reasons for neuralism are more "metaphysical;" hence, I tried to offer an alternative metaphysics. Juarrero calls this a "facile dismissal," and she is entitled to her opinions about what counts as facile. But Juarrero doesn’t say what she thinks is wrong with my attempts to deal with the questions (concerning overdetermination/supervenience/causation) one has to deal with, if one rejects neuralism. (She also says in her first paragraph that "the thesis Pietroski sets up to demolish is in fact something of a red herring." Which led me to wonder: can one facilely dismiss a red herring?)

Oddly, Juarrero quotes my (apparently nondismissive) claim that "Certain abstract (metaphysical) considerations about causation can make it difficult to see alternatives [to neuralism]." But she also says that

the opportunity to reconsider those "abstract metaphysical considerations about causation" is allowed to slip away.

What does Juarrero make of chapters 3 and 7, which are devoted to saying how explanation and causation hang together, in ways that make it possible for us to say that mental causes are causes distinct from any biochemical causes? What does she make of my repeated claims (following Tyler Burge and others) that we need to subject easy metaphysical assumptions about causation to scrutiny—since they may be the trouble-makers? The interpretive conundrums deepen:

If (1) wholes are reducible to the fusion of their parts, (2) if the only model of causation available for abstract metaphysical reasons is a chain of "topplings," and (3) if mental events are "inner" events distinct from –not merely different descriptions of N1...Nz (and are in some sense inner to the agent or person – to me – not just the body), then, ontologically, what are mental events? Where and when are they?

Now I did say some things about (3). But I rejected (1). And perhaps the central point of my book is that (2) is false. Again, chapters 3 and 7 are devoted to the idea that an event C caused an event E if a true thought about (the occurrence of) C explains if a true thought about (the occurrence of) E. So far as I can tell, Juarrero makes no reference to this part of the book.

Perhaps her most striking claim, though, is the following:

Unlike merely neural, biochemical changes, Pietroski claims, mental events are global changes in the brain.

Juarrero provides no page reference for this one. But exegesis aside, why would an event dualist hold that mental events are changes in the brain?

As for Juarrero’s remarks about vagueness, I think they are also off target. There are indeed hard issues here, as Noordhof’s comments nicely brought out. But they have nothing to do with "mechanics", Newtonian or otherwise. And why would I commit myself to Newton’s (or Descartes’) picture of the physical world, much less apply that picture to the mental world, given that (as I mentioned in chapters 5, 6, and 7) we’ve had to revise that picture for reasons discovered by physicists?

3. I have nothing useful to say about the second section of Juarrero’s paper. But let me end by addressing her speculation that

in the brain, coherent wave patterns of a far greater dimensionality than those of the individual neural events that constitute them, and embodying the emergent properties of consciousness and meaning (Pietroski’s personal, rationalizing features) appear as neurons entrain and self-organize into global structures. These higher levels of dynamical organization (not merely spatio-temporal organization, as Pietroski suggests), impose second-order, context-sensitive constraints on their components (Pietroski’s impersonal, merely neuronal features).

Now I never suggested that mental events differ from biochemical events merely in terms of spatiotemporal organization. (I carried on, at some length, about rationalization and mental content and person-level descriptions.) But for all I know, "high dimensionality wave patterns" may explain a lot. Still, as the exchange with Noordhof brought out, I do worry that identifying reasons with biochemical occurrences (of any kind) threatens to efface my agency. I’m hardly the first philosopher to have this worry; and perhaps those of us who have this worry need some kind of therapy. But that needs showing. And I don’t see how appeal to wave patterns, dimensions, or "second-order context-sensitive constraints" speaks to the concern—unless coupled with a substantive account of how such things can be (or can constitute, in some sense that doesn’t reintroduce the old problems in new terms) my reasons and actions. Reasons are causes, but that’s where the philosophical work begins; and there is work to be done, one way or another. I suggested a certain way of approaching the task. And I suggested that we assess philosophical theses, at least in large part, in terms of how they help us resolve the puzzles we want to resolve.

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