In September of 2012, the eminent philosopher Thomas Nagel published a calm and dispassionate book challenging the reigning scientific orthodoxy of the day. In his book Mind and Cosmos, Nagel argues that the current materialist, neo-Darwinian explanatory model cannot account for the existence of consciousness, reason and value. Nagel also criticizes the standard scientific approaches to both the origin of life and the evolution of species towards greater complexity. In its stead, Nagel refuses to adopt what has currently been seen as the only alternative to materialist neo-Darwinism, namely, theism. Rather, Nagel envisions a third way -- what he calls ‘natural teleology' -- a view that makes room for purposes embedded in nature, but without the need for a Designer. Nagel is an atheist who recoils from theism, but he simply doesn't believe that the current evolutionary stories and the framework that provides their context, or even future stories working from within this very framework, will ever be sufficient to account for some of the most puzzling features of our universe.
In response to Mind and Cosmos, except for the generally positive review by Alvin Plantinga in The New Republic, Nagel has received a fusillade of criticism. Yet what stands out in some of the responses is the lack of serious engagement with Nagel's arguments. This failure of the critical imagination is most evident in Brian Leiter and Michael Weisberg's (L&W) critique of Mind and Cosmos, published in The Nation (Do You Only Have a Brain? On Thomas Nagel, October 2012). Despite the review's basic flaws, the New York Times christened it the “takedown” of Thomas Nagel.
In their review, L&W confuse description with ontology, bungle the relationship between explanation and prediction, fail to address the central problem of consciousness, mislead readers regarding Nagel's argument on the incompatibility between evolution and moral realism, and mischaracterize Nagel's appeal to common sense. L&W are well-regarded philosophers affiliated with prestigious institutions and, no doubt, they needed to compress their arguments into a form and manner suitable for public consumption. Nevertheless, the result is a review entirely lacking in rigor, and is anything but the “takedown” of Nagel that so many would cherish.
L&W begin their critique by pointing out that Nagel doesn't quite have his target right. Nagel's book is an attempt to cast doubt on the project of theoretical reductionism -- the attempt at reducing all the facts of chemistry, biology and the social sciences to the level of physics. But according to L&W, this theoretical reductionism -- which forms the ostensible target of Nagel's challenge -- is more a figment of Nagel's imagination than a genuine research project, since many materialists have in fact disavowed the theoretical reductionism that Nagel purportedly challenges:
Nagel here aligns himself, as best we can tell, with the majority view among both philosophers and practicing scientists. Just to take one obvious example, very little of the actual work in biology inspired by Darwin depends on reductive materialism of this sort; evolutionary explanations do not typically appeal to Newton's laws or general relativity. Given this general consensus (the rhetoric of some popular science writing by Weinberg and others aside), it is puzzling that Nagel thinks he needs to bother attacking theoretical reductionism.
So according to L&W, Nagel is challenging a theoretical reductionism which materialists have already disowned. The problem here is that L&W confuse description with ontology. It is true that many materialists do not believe that evolution, or photosynthesis, or marriage, or banking, or any other “higher-level” facts or processes or conventions can be captured or re-described in the language of physics. Biology and the social sciences will not soon go out of business. But this, say the materialists, is simply a problem of description, of our incapacity to map ‘higher-level' facts and events onto the elementary particles out of which they are comprised. But at the level of ontology -- at the level of what the constituents of reality are ultimately composed of -- materialists agree that there is nothing over and above the elementary particles, forces and fields described by physics. We may not be able to describe how biological or social facts fit onto particle-talk, but that is due to a failure of our limited human capacity to trace the detailed connections between the laws of physics and natural selection or any other ‘higher-level' facts.
And the larger point is this: not a single one of Nagel's arguments is affected by this qualification of the materialist enterprise. Materialists agree that nothing exists beyond the particles and forces described by physics, and Nagel's arguments are designed to challenge that worldview. L&W simply trot out a red herring – that Nagel doesn't describe the materialist project correctly – a claim that confuses description with ontology and fails to undermine even a single one of Nagel's arguments.
Perhaps the most glaring defect of L&W's review is not what is stated, but what is omitted. It is surprising, to say the least, that in what is supposed to be a devastating critique of Mind and Cosmos, L&W manage to almost entirely ignore or bypass the driving force in Nagel's attack on materialism -- the problem of consciousness. Nagel has been thinking about this problem longer than almost anyone else. In 1974 he published his now-classic article, “What Is It Like to Be a Bat?” arguing that it is implausible to conceive of subjective experience as a feature of a purely physical universe. Nagel's argument in Mind and Cosmos is in part an extrapolation of that claim. If matter cannot account for or explain mind, as Nagel has consistently argued, it follows that evolutionary theory -- insofar as it operates within an exclusively-materialistic framework -- will also be unable to account for mind. And here is L&W on the central problem of the materialist worldview:
We agree with Nagel that if the sciences could not explain our capacity to have thoughts about the world around us, that would be a serious failing and a reason to call their findings into question. But they can and they do! It is here that Nagel's lack of engagement with contemporary cognitive science…make his argument especially perplexing.
That's it -- this is the sum total of L&W's views on the problem of consciousness: that advances in cognitive science are to supposed to hold the key for how we are to conceive of consciousness and subjectivity in physical terms. This claim is simply incredible as it stands today, for nothing that has come out of the cognitive science field has remotely come close to solving the hard problems of consciousness -- of how subjectivity and first-person experience are to be understood as physical features of brains or organisms. This “response” to Nagel's central contention reveals the shallowness of much of L&W's critique, which fails to distinguish between the relatively ‘easy' problem of consciousness, such as that of understanding how memory and perception work, which advances in cognitive science can indeed shed light on, and the ‘hard' problem of consciousness (as the philosopher David Chalmers has dubbed it) - that is, understanding the subjective, first-person, experiential nature of consciousness -- what consciousness feels like from the inside -- in which hardly any advances have been made. In Jon Dupre's review of Mind and Cosmos, he wonders why matter can't arrange itself in such a fashion that it can lead to complex processes like ‘experience.' But Dupre's approach is also an evasion, for the real problem isn't complexity, it's subjectivity, and no one has the foggiest idea of how first-person subjectivity is supposed to be a physical feature of an organism.
For Nagel, the problem of consciousness reaches all the way down. If we cannot explain consciousness in material terms, it follows that evolutionary biology -- insofar as its assumptions are thoroughly materialistic -- would also be unable to explain consciousness. But L&W believe that Nagel has set the bar too high for what constitutes an adequate explanation. According to Nagel, a materialist understanding of evolution would prove singularly unable to predict the kinds of organisms that are likely to arise, replete with mind and consciousness. And if explanation and prediction go hand-in-hand, as Nagel thinks they should, it follows that failure to predict the emergence of consciousness must be based on a corresponding failure to explain. We are not in a position to predict what is likely to come because we just don't understand what's really going on.
But L&W demur, and challenge Nagel's connection between explanation and prediction. Sometimes, say L&W, we can explain without being able to predict:
This idea, however, is inconsistent with the most plausible views about prediction and explanation, in both philosophy and science. Philosophers of science have long argued that explanation and prediction cannot be fully symmetrical, given the importance of probabilities in explaining natural phenomena. Moreover, we are often in a position to understand the causes of an event, but without knowing enough detail to have predicted it. For example, approximately 1 percent of children born to women over 40 have Down syndrome. This fact is a perfectly adequate explanation of why a particular child has Down syndrome, but it does not mean we could have predicted that this particular child would develop it. Causes alone are frequently deemed sufficient to explain events; knowing enough to predict those events in advance is an important scientific achievement, but not essential to explanation.
It is true that probabilistic explanations can at times be provided for natural phenomena, as L&W show, and that such explanations cannot always be used to generate accurate predictions. A well-known example (used by Elliott Sober in his review of Mind and Cosmos) is our inability to predict the gender of a newborn, which is based on the probabilistic laws of genetics. Yet no one would deny that we have a decent understanding of the processes involved in conception and birth. Nonetheless, we cannot use our adequate explanations to predict the gender of a baby.
Unfortunately, L&W ignore a crucial distinction. In the case of gender and the laws of genetics, we know enough to predict with almost absolute certainty that the next baby will either be a boy or a girl, and that such a baby will have certain features (the features that make an organism human). There are significant and detailed constraints, known by us in advance, regarding what kinds of babies we can expect. But with respect to evolutionary explanations, knowing how evolution works from a purely materialistic framework would not have enabled us to predict even the general contours of conscious organisms that would eventually arise. This is the difference between failing to predict tokens of organisms -- a minor problem and one that does not call into question the adequacy of our understanding -- and failure to predict types of organisms -- a significant failure that casts doubt on the adequacy of the explanation. As Nagel writes: “An explanation must show why it was likely that an event of that type occurred.”(47) L&W do nothing to dispel Nagel's claims that we lack a genuine explanation where we cannot even figure out what kinds of organisms are likely to arise based on our understanding of evolutionary processes. L&W here simply don't grasp the argument in Mind and Cosmos.
For Nagel, the reality of mind forms the central problem for a Darwinian, materialist worldview. Nagel extends his argument by showing that some particular workings of the mind pose different, and equally insuperable, problems for evolutionary theory. For instance, our minds engage in reasoning about values, and Nagel challenges the neo-Darwinian framework by arguing that if neo-Darwinism is true, moral realism -- the claim that certain moral judgments are true independent of anyone's beliefs or attitudes -- is false. This is a serious claim -- that one cannot believe in both the truth of evolutionary theory and in objective moral truths, independent of our evaluative attitudes.
Nagel's argument for the incompatibility between evolution and moral objectivity revolves in part around a contrast between perception and morality. Nagel points out that there is nothing adaptive about moral objectivity as such, in contrast to the objectivity of our perceptual judgments. For example, it is clear that if you can't see lions in the forest, you are not likely to survive for long. Perceptual accuracy and objectivity confer obvious advantages for survival. But that is not the case with moral objectivity. What is adaptive or what helps a species or organism survive are the actual moral behaviors and tendencies, not the objective reliability or truth of those behaviors. In other words, the capacity to discern objective moral truths would not have been selected for, and is, therefore, from an evolutionary standpoint, superfluous. Nor is it plausible, for various reasons, to suppose that our ability to ascertain objective moral truths is a
-- an accidental by-product of capacities which were themselves adaptive.
There is, of course, much more to the argument, which is spelled out in detail by Nagel's colleague at NYU, Sharon Street. Nagel and Street are touching on a deep and confusing problem regarding the relationship between adaptation and moral truth, for why should our moral judgments be binding on us if they are in large part the result of seemingly amoral, random mutations and contingent selective pressures?
And here is how L&W deal with the argument for the incompatibility between evolution and objective moral truths:
We take no stance on Nagel's hypothesis that if our moral faculties are simply the result of evolution, they cannot be reliable measures of objective moral truth. But we should note that Nagel's colleague, philosopher Sharon Street, accepts it and draws the opposite conclusion. She argues that because this hypothesis is true, and because we are obviously the products of evolution, we should give up the idea that there are objective moral truths in Nagel's sense. Given the philosophical plausibility of Street's alternative response—not to mention the simplistic evolutionary reasoning the whole debate is predicated on—it is hard to see why any biologist should be given pause by Nagel's argument.
L&W take no position on whether evolution and moral objectivity are incompatible. Instead, they simply decide to jettison the objectivity of moral values. This may be fine for some philosophers, but we can be certain that there are many scholars and scientists, evolutionary biologists among them, who would be flabbergasted by the requirement to drop the objectivity of moral values ‘in Nagel's sense' at the cost of inconsistency, and it is to them that the argument is also directed. Not a word of L&W's criticism touches this central issue.
But what is most striking in L&W's ‘critique' of Nagel here is that they fail to mention that it is Nagel himself who introduces us to Street and who makes precisely the same counter-argument that L&W invoke against his position. Indeed, Nagel spends almost five pages summarizing Street's argument and her conclusion. While both Street and Nagel agree that evolution and moral realism are incompatible, a serious charge in its own right, “Street concludes that realism cannot be right; I conclude that something is missing from Darwinism…”(111)
So Nagel is explicit that you can jettison moral objectivity as a way out of his conundrum. Why then, do L&W invoke Street and her ‘solution' without bothering to mention that Nagel has addressed all this in his book? If you are going to critique an author's argument, you should at least point out that the criticism proffered has been addressed in the book, and in fact is lifted from the book. Nagel knows that you can abandon moral objectivity as a way out, but his argument is also directed at those who want to have their cake and eat it too -- at the legions of scholars and scientists who believe in both the standard account of evolution and in a realist version of the objectivity of values. L&W's presentation of Nagel's argument in this section is simply disingenuous.
In various parts of his book, Nagel often makes appeals to common sense, in particular to our common sense understandings of consciousness. It is incontrovertible that consciousness is real and that, in Nagel's memorable phrase, “there is something it is like” to experience pain or feel angry. Now these incontestable experiences act as a strong rebuke to a world-view that would equate our consciousness with objective, physical features. L&W, however, find Nagel's appeal to common sense to be quixotic, for after all, science is in the business of refuting common sense. We all used to think the earth was flat, now we know better. Why should our common sense understandings of consciousness be any different?
But consciousness is different. This, after all, is Nagel's point in his seminal article on bats and minds, and informs his central chapter on consciousness in Mind and Cosmos. When science undoes a common sense image of the world, such as when it shows that the world is a sphere, it is replacing one image of how the world actually is with another more accurate one. That is, science shows us that our appearances can sometimes be illusory. But that cannot be the case with consciousness, for there is no distinction between appearance and reality with respect to consciousness - how things “appear” to us just is the reality. When we genuinely feel pain, scientists cannot come along and tell us that in reality, such pain is nothing but a tendency to behave in certain ways or that the pain is in reality the firing of certain neurons. That can't be pain, for pain is what it feels like to be in pain, and no amount of behavioral, functional or brain-state talk can show us that the subjective feeling of pain is an illusion, or that there is something more basic than the pain-experience that pain really is. Consciousness can't be shown to be an illusion -- an appearance with no basis in reality -- like a flat earth, for consciousness just is how things appear to us. L&W draw a misleading analogy between consciousness and a flat earth and mischaracterize Nagel's appeal to common sense because they consistently evade Nagel's central challenge regarding the bewildering relationship between matter and mind. Philosophical reflection bolsters our common sense intuitions that consciousness is real and that subjectivity is unlikely to eventually be revealed as an essentially physical phenomena. It turns out then, that our common sense understandings of consciousness are on much more solid ground than L&W suppose.
Over 800 years ago, the philosopher Maimonides cautioned us not to think of ourselves as the pinnacle of creation, as the reason for the existence of the universe. We would do well to heed his warning against unchecked hubris. But just because we are not the center doesn't mean that we are accidents. Thomas Nagel's attempt to re-invigorate ‘natural teleology' as an explanatory model is borne of a deep and abiding intuition -- that the ability of human beings to reason, to experience and to perceive genuine value in the world is not an accident. Nagel's critics are right to point out that he has not yet provided us with a positive vision in sufficient detail, and that ‘natural teleology' cannot at this time serve as the basis for future scientific research. Much work remains, as Nagel would be the first to admit. But it is time for his critics to stop making specious comparisons between outdated beliefs in a flat earth and our deep intuitions that standard evolutionary theory cannot account for some central and puzzling features of our world. Until we come to terms with the force of that intuition – given impressive argumentative form and depth by Thomas Nagel in Mind and Cosmos, we will not gain in understanding.