Saturday, November 17, 2012
Nagel and his critics, Part III
In the previous installment in this series of posts on Thomas Nagel’s Mind and Cosmos, I looked at some objections to Nagel raised by Brian Leiter and Michael Weisberg. I want now to turn to Elliot Sober’s review in Boston Review. To his credit, and unlike Leiter and Weisberg, Sober is careful to acknowledge that:
Nagel’s main goal in this book is not to argue against materialistic reductionism, but to explore the consequences of its being false. He has argued against the -ism elsewhere, and those who know their Nagel will be able to fill in the details.
Sober then goes on to offer a brief summary of the relevant positions Nagel has defended in earlier works like his articles “What Is It Like to Be a Bat?” and “The Psychophysical Nexus.” As I emphasized in my previous post, keeping these earlier arguments in mind is crucial to giving the position Nagel develops in Mind and Cosmos a fair reading. Unfortunately, however, having reminded his readers of these earlier arguments of Nagel’s, Sober immediately goes on to ignore them.
Sober on Nagel and evolution
In the first half of his review, Sober focuses on Nagel’s criticisms of evolutionary theory. Summarizing the first of these criticisms, Sober writes:
Nagel thinks that adequate explanations of the origins of life, intelligence, and consciousness must show that those events had a “significant likelihood” of occurring: these origins must be shown to be “unsurprising if not inevitable.” A complete account of consciousness must show that consciousness was “something to be expected.” Nagel thinks that evolutionary theory as we now have it fails in this regard, so it needs to be supplemented.
Sober then goes on to complain:
Nagel doesn’t impose this condition of adequate explanation on all the events that science might address. He is prepared to live with the fact that some events are just flukes or accidents or improbable coincidences. For example, it may just be an improbable coincidence that in the mid-1980s Evelyn Marie Adams won the New Jersey lottery twice in the span of four months. But the existence of life, intelligence, and consciousness are not in the same category. Why do Nagel’s standards go up when he contemplates facts that he deems “remarkable”? Maybe the answer falls under what Nagel refers to, in a different context, as his “ungrounded intellectual preference.” It isn’t theistic conviction that is doing the work here, but rather Nagel’s faith that the remarkable facts he mentions must be “intelligible,” where intelligibility requires that these facts had a significant probability of being true.
End quote. The trouble, though, is that Sober is here just making the same mistake which, as we saw in my previous post, Leiter and Weisberg make in their review. Nagel’s point has nothing to do with “ungrounded intellectual preferences” nor even with mere improbability as such, at least not on a charitable interpretation of his position. Start with consciousness. As I noted in response to Leiter and Weisberg:
If the argument of “What Is It Like to Be a Bat?” is correct, then it is not merely improbable that what Nagel there calls “objective” facts should by themselves give rise to [the] “subjective” facts [of consciousness], but impossible, for they differ qualitatively rather than merely quantitatively. To borrow an example used by the Thomist William A. Wallace in another context, a polygon is just a different sort of thing from a circle, no matter how closely you approximate a circle by adding sides to a polygon. And that a circle might arise from nothing more than the successive addition of sides to a polygon is therefore not merely improbable or unpredictable; it is impossible in principle. Similarly, given the difference between “objective” and “subjective” facts as Nagel characterizes them, you are simply not going to get the latter from the former alone even in principle. At any rate, if Nagel is wrong about this, Leiter and Weisberg haven’t done anything to show that he is, but have merely implicitly assumed that he is.
Similarly, Nagel holds that it is in principle impossible to understand rationality in purely evolutionary terms -- that the reliability of our rational faculties is never going to be entirely explicable merely in terms of the selective advantage they may have conferred on us -- for reasons spelled out in his book The Last Word and sketched out more briefly in the current book.
Now Sober might respond that this objection of mine presupposes Nagel’s critique of materialistic reductionism and some of his other philosophical arguments, whereas what he (Sober) is concerned to respond to is a separate, distinct criticism of evolutionary theory that does not presuppose these particular philosophical arguments of Nagel’s. For Sober writes:
Nagel believes that evolutionary biology is in trouble, but what sort of trouble is it in? There are two possibilities. Evolutionary theory could be in trouble just because it is committed to materialistic reductionism; if so, the theory would be perfectly okay if it dropped that commitment. Understood in this way, it’s the philosophy that has gone wrong, not the biology. But much of what Nagel says is not in this vein. He thinks that the biology itself is flawed. Even without a commitment to materialistic reductionism, the theory would be in bad shape. For Nagel, the combination of evolutionary theory and materialistic reductionism is false, while evolutionary theory taken on its own (without the philosophical add-on) is incomplete. Incompleteness means that the theory cannot fully explain important biological events.
End quote. It seems to me, though, that Sober is in this case responding to an argument that Nagel does not in fact give in the first place, at least not with respect to consciousness and rationality. That is to say, Nagel’s reason for saying that consciousness and rationality cannot be explained in evolutionary terms just is that such an evolutionary explanation (as evolution is typically understood today, anyway) would be a materialistic explanation, and no such explanation can succeed. Nagel doesn’t have some separate argument to the effect that consciousness and rationality are evolutionarily improbable even apart from their being inexplicable in materialistic terms. The reason he thinks current evolutionary theory is “incomplete” just is that it limits itself to materialistic explanations; it’s not that there is some other respect in which it is incomplete that makes consciousness and rationality improbable even apart from the issue of materialism. What would “complete” it is precisely a non-materialistic underlying metaphysics.
Nagel’s views on the origin of life do seem, I acknowledge, to be of a different sort. Here I think his objections do amount at least in part to the claim that life is improbable for reasons that are not essentially connected to the arguments of earlier works like “What Is It Like to Be a Bat?” or The Last Word. They appear to have instead to do with considerations of the sort that “Intelligent Design” theorists have put forward. But Sober should not run what Nagel says about consciousness and rationality together with what he says about the origin of life. In Mind and Cosmos, Nagel explicitly contrasts the kind of difficulty he thinks faces an explanation of the origin of life with the kind he thinks faces an explanation of consciousness, writing: “But to explain consciousness, as well as biological complexity, as a consequence of the natural order adds a whole new dimension of difficulty” that requires that something be “added to the physical story” (pp. 49-50, emphasis added).
But even if Nagel did have a separate, non-philosophical argument against the adequacy of an evolutionary account of consciousness and rationality, it would odd for Sober to put so much emphasis on it, because the philosophical, anti-materialist argument from the inexplicability of “subjective” facts in terms of “objective” facts is (as Sober’s earlier remarks implicitly acknowledge) a distinctively Nagelian sort of argument, and a more philosophically interesting line of argument. By neglecting to respond to it, Sober is failing to take Nagel on at his strongest point -- never a good thing in philosophy, and especially not when one is purporting to show that “Nagel has not made a convincing case.”
To be sure, Sober himself may be hinting at the way of interpreting Nagel that I have been suggesting when he writes:
What makes more sense than Nagel’s probability requirement is one about possibility—that an adequate theory must allow that the origin of life, mind, and consciousness all were possible, given the initial state of the universe. If this were all that Nagel meant by his claim that “the propensity for the development of organisms with a subjective point of view must have been there from the beginning,” I would have no quarrel. But then there would be no objection to the sciences we now have.
But it is not clear what Sober intends to concede here. Is he acknowledging that Nagel is right to hold that you are never going to get what he calls “subjective” facts from “objective” ones alone (in Nagel’s technical senses of those terms), so that physical science should not confine itself to the latter? If so, then it is hardly plausible to say that that is “no objection to the sciences we now have,” at least given the way philosophical naturalists (including many scientists themselves) typically interpret the sciences. Or is Sober agreeing with Nagel that these naturalists are just mistaken in thinking that science ought to proceed in a materialist fashion? If so (though I doubt it), then good for Sober, but this is hardly a minor or non-controversial point!
Sober also takes issue with Nagel’s claim that objective moral value cannot be explained in evolutionary terms. As with Leiter and Weisberg’s treatment of this subject, I’m going to refrain from commenting since my meta-ethical views differ from Nagel’s to such an extent that saying what I would want to say would require too lengthy a digression into moral theory.
Sober on Nagel on teleology
Even apart from what has already been said, Sober’s point about probabilities is mistaken. For the example of someone winning the lottery twice is simply not relevantly comparable to the existence of consciousness and rationality. The former is a one-off event, or at most the sort of thing that happens very sporadically and unpredictably. But the latter are ordinary features of the biological realm at least at its higher levels, occurring with regularity and predictability. The former would be a paradigm case of what Aristotelians would consider a chance event, whereas the latter would be instances of what Aristotelians would consider paradigmatic regularities.
This brings us to Sober’s remarks on teleology. For the Aristotelian, chance presupposes regularity. To take a stock example, when a farmer plows his field and comes across buried treasure, that is a chance event. But it occurred only because of two non-chance events -- someone deciding to bury treasure at that spot, and the farmer deciding to plow the field on that day. In general, chance occurrences involve the convergence of causal factors that are instances of regularity rather than chance, as when a piece of toast burns in such a way that it looks vaguely as if there is a face on it (chance) but only because someone had put the toast in the toaster, the toaster was operating as it always does, etc. (regularity).
Now as the Aristotelian conception of causality was developed within the Scholastic tradition, all efficient-causal regularities presuppose final causality or teleology in the sense that unless an efficient cause A were inherently or of its nature “directed toward” the generation of some effect or range of effects B, specifically, there would be no reason why it does in fact generate B specifically rather than some random effect or no effect at all. (Whether this final causality or teleology in turn requires a divine cause is a separate question, which need not be settled for the purposes at hand; and of course, Nagel wants to affirm teleology without a divine source.) So, for the Aristotelian, chance presupposes regularity, and regularity in turn presupposes teleology. Hence even chance occurrences like winning the lottery twice ultimately presuppose teleology. Hence they can hardly coherently be appealed to in an argument against an Aristotelian teleological conception of the world.
Now Sober writes:
According to Nagel a teleological theory says that things tend to change in the direction of certain types of outcome. This is right, but, as Nagel realizes, it isn’t sufficient for a theory to be teleological.
But for the Aristotelian-Scholastic philosopher, “that things tend to change in the direction of certain types of outcome” is indeed “sufficient for… teleolog[y],” at least a very simple kind of teleology. It might be that Sober does not see the possibility of such a view because, like so many contemporary philosophers, he may be thinking of teleology in essentially biological and/or artifactual terms, and thus assumes that to attribute teleology to something necessarily involves attributing to it something like a function of the kind served by a bodily organ or the component of a mechanical device. But for the Scholastic tradition, that is only one kind of teleology among others. Mere directedness to a certain outcome of the sort manifest in even the simplest inorganic causal processes involves a very rudimentary sort of finality or teleology. And one needn’t be a Scholastic to take such a view; as I have noted many times, contemporary “new essentialist” and “dispositional essentialist” metaphysicians and philosophers of science (George Molnar, C. B. Martin, John Heil, et al.) are committed to something like it insofar as they regard the directedness of causal powers toward their effects or the directedness of dispositions toward their manifestations as instances of “physical intentionality” or “natural intentionality.”
Hence, while Sober says that he “do[es] not reject teleology wholesale” as long as there are “causal underpinnings for… teleological statements” -- that is to say, as long as claims about teleology or final causality can be cashed out in terms of claims about patterns of efficient causation -- what he does not see is that the whole point, from the Aristotelian-Scholastic point of view, is that the latter sort of claim, claims about efficient causation, themselves presuppose finality or teleology. For without finality or teleology there is no way for there to be efficient causal regularities in the first place. Reducing some instance of teleology to efficient causality, then, merely puts off the inevitable, because the efficient causality will itself have to be explained in teleological terms.
In fairness to Sober, Nagel himself does not say all this; his own appeal to Aristotelian teleology is very sketchy, and (as I complained in an earlier post) he does not make use of or even refer to the work of “new essentialist” and other contemporary neo-Aristotelian writers -- many of whom are, like Nagel, writing from a secular point of view -- who have developed the relevant ideas in more systematic detail.
Still, the existence of this body of largely secular neo-Aristotelian work within contemporary mainstream academic philosophy only reinforces Nagel’s main point that philosophers in general need to take non-materialist views more seriously than they do. And that Sober does not consider these existing alternative views only reinforces Nagel’s complaint about the narrowness of the “right-thinking consensus” within academic philosophy that he is trying to challenge. Even the difficulties with the consensus tend to get interpreted a way that is claimed somehow to favor the consensus. So beholden are so many philosophers to it that they cannot even see when their position has essentially been undermined. Hence Sober writes:
Nagel is hardly unique in being an anti-reductionist. Most philosophers nowadays would probably say that they are against reductionism.
What sets Nagel apart is his idea that current biological and physical theories need to be fundamentally overhauled. Why do other anti-reductionists decline to take this radical step? It is not that they are faint of heart. Mostly they decline because they endorse the following picture. When an organism has a new visual experience, the physical state of the organism has changed. And when an economy goes into recession, the physical state of that social object also has changed. These examples obey the slogan I mentioned before: no difference without a physical difference.
However, when it comes to understanding visual perception and economic change, the best explanations are not to be found in relativity theory or quantum mechanics. Sciences outside of physics can explain things that physics is not equipped to explain. But this doesn’t mean that physics needs to be revised. The philosophers and scientists I am describing disagree with Nagel’s claim that evolution is more than a physical process, though they agree that physics is not the best tool to use in understanding evolution.
End quote. What Sober does not see is that the picture of the natural world implicit in these remarks is itself an essentially anti-materialist one insofar as it acknowledges that there are higher-level features of material objects that cannot be captured entirely by a description of their micro-level parts. It constitutes an implicit abandonment of the mechanistic conception of matter we’ve inherited from Galileo, Descartes, Boyle, and Co., which was inherited by them in turn from the ancient atomists, and which has always been implicit in the materialist tradition. To be sure, one could take this anti-reductionism in one of two directions -- either in the direction of post-Cartesian forms of dualism, whether substance dualism or property dualism (which more or less preserves the mechanistic conception but adds a further layer of reality to it), or in the direction of hylemorphism (which abandons the mechanistic conception altogether in favor of a conception of material substances as composites of substantial form and prime matter).
The first option is the one taken by Cartesian dualists and by “naturalistic” property dualists like David Chalmers; the second option is the one taken by neo-Aristotelians. Either one involves just the sort of radical overhaul of the naturalistic conception of the world that Nagel is calling for, but which Sober, like Leiter and Weisberg, think is unnecessary. They think this in part because they do not see that an “anti-reductionistic materialism” is indeterminate, and when made more precise either collapses back into reductionistic materialism or amounts to property dualism or hylemorphism rather than materialism; and in part because (as Sober’s remarks indicate) they suppose that the supervenience thesis that there is “no difference without a physical difference” somehow entails an essentially materialist position. But it does not. For that there is no difference without a physical difference would show only that the micro-level physical facts are necessary for the higher-level facts, not that they are sufficient. And that is something either a property dualist or an Aristotelian could accept. The Aristotelian, after all, regards a natural substance’s material cause as no less an irreducible constituent of it as its formal cause.
(To be sure, a qualification to the supervenience thesis would be required in the case of strictly intellectual activity, which -- unlike sensation, imagination, digestion, locomotion, etc. -- is, for the Aristotelian, a partially immaterial operation of the human organism. But that is irrelevant to the point at hand, which is that even in the case of entirely material substances and operations, supervenience does not entail materialism.)
But I don’t mean to be too hard on Sober, who is a serious thinker and who, both in the present review and elsewhere, has shown himself to be fair-minded. Indeed, at the end of his review of Nagel, he writes:
I realize that Nagel is trying to point the way to a scientific revolution and that my reactions may be mired in presuppositions that Nagel is trying to transcend. If Nagel is right, our descendants will look back on him as a prophet—a prophet whom naysayers such as me were unable to recognize.
That, I think, is precisely what is going on -- the “presuppositions that Nagel is trying to transcend” run so deep in contemporary academic philosophical culture that it is difficult for most philosophers to get any critical distance on them. They lack, as Nietzsche might have said, the courage for an attack on their own convictions. And yet the evidence that there is something deeply wrong with the naturalistic consensus is all around them even in “mainstream” academic philosophy -- in the work of renegade naturalists like Nagel, Searle, Fodor, McGinn, et al.; dualists like Chalmers, Brie Gertler, Howard Robinson, John Foster, et al.; and neo-Aristotelians like the “new essentialist” metaphysicians and philosophers of science (Cartwright, Ellis, Martin, Heil, Mumford, et al.) and the analytical Thomists (Oderberg, Klima, Haldane, et al.). It’s psychologically easy (even if philosophically sleazy) to dismiss one or two of these thinkers as outliers who needn’t be taken seriously. But as their ranks slowly grow, it will be, and ought to be, harder both psychologically and philosophically to dismiss them.
Which is no doubt why the more ideological naturalists would very dearly like to strangle this growing challenge to the consensus while it is still in its crib -- hence the un-philosophical nastiness with which Nagel’s views have been greeted in some quarters. But Sober, to his credit, is not an ideologue, and is sober enough to acknowledge at least the possibility that Nagel is on to something. As I have tried to show, his reasons for demurring fail to get to the heart of Nagel’s critique.
So, Nagel passes this particular “sober test.” Good thing he didn’t get the one Steve Martin got in The Man With Two Brains!