This important book consists of two quite distinct advocacies for a consilience of the sciences and the humanities. Ed Slingerland refers to the goal as “vertical integration,” the humanities to be stacked in layers of emergence atop another stack of the material sciences, the whole pile resting on a foundation of quark and atomic physics. In his super-reductionist vision each layer is to look for its meaning in how it is accounted for by those below it.

One advocacy, cautious and lavishly-referenced, to me as a layman rather tedious, and occupying most of the book, is addressed exclusively to his fellow practitioners in the humanities. His aim is to offer “a way for humanists to steer between the Scylla of objectivist intellectual imperialism and the Charybdis of the postmodern ‘prison house of language’” This section of the book consists of detailed but restrained attacks on excesses of both these scourges of the academy, ending with a spirited celebration of the middle way, which he identifies with common sense. Common sense, then, according to this advocacy, is the standard under which he hopes to unite his fellow humanists.

The other advocacy for a thoroughgoing consilience appears exclusively in Chapter 6. Here I found a wonderful defense of material monism, far more persuasive than the Dawkins, Dennetts and Flanagans of this world. Slingerland is so persuasive because he drops his caution and launches into a passionate personal account of his beliefs. At the same time, he acknowledges fully and fairly, as something he experiences, that dualism is a more accurate and more comforting record of our experience. I found his testimony in favor of common sense very disarming.

What inclines someone to material monism? Temperament, I believe. Slingerland as material monist: “It is important to realize that any truly interesting explanation of a given phenomenon is interesting precisely because it involves reduction of some sort—tracing causation from higher to lower levels or uncovering hidden correlations.” For me the opposite is true; reductionism is useful but not interesting; it is not synonymous with uncovering hidden correlations. I got further insight into the reductionist temperament from a reference Slingerland makes to a monograph he wrote on his primary field of study, ancient Chinese thought. He showed how “a tension internal to a spiritual ideal” shared by five early Chinese thinkers “motivated much of their theorizing about human nature and self cultivation.” He refers to his “trying to show how five apparently disparate texts could, in fact, be seen as motivated by a single, ‘deeper,’ shared goal and common conceptual tension” as an example of reductionism. To me it’s the opposite. Suppose I wanted to account for the fingers of one ancient thinker tracing their way across the page, I could do this in terms of muscles, nerve impulses, biochemistry and eventually physics and quantum effects. That would be reductionism. But I could also account for it by transcendent causes: the scholar’s belief in a concern for human nature and self cultivation. How can both directions be regarded as reductionist? I see Slingerland tending to hijack all forms of explanation into a reductionist straightjacket. For him, explanation of any kind seems to amount to reductionism.

Slingerland’s passions for both common sense and reductionism lands him in an agonizing tug-of-war. On the one side he respects and feels the appeal of a common-sense dualism as much as anyone can (though he dutifully quotes others referring to it as “mysterian," a polite way of saying "supernatural"). On the other side his passion for reductionism pulls him towards a scientific hypothesis that, if true, would support materialist monism. In such a situation, what would you do? Most of us would question, first, common sense, and then, the monist hypothesis. That Slingerland won’t do, Rather than question that hypothesis he abandons, with much sadness, common sense. And what is the hypothesis supporting a strict reductionism he refuses to question? Darwinism! He refers to “evolution and natural selection” as if they form an indissoluble pair. On page 251 he says, “there do not currently appear to be any empirically viable alternatives to the physicalist position,” yet he spends no time considering the possibility. There is no mention of Lamarckism, for example—surely worth a mention in such an analysis. Finding in Darwinism a suitable object for his reductionist passion, he looked no further.

Slingerland’s Chapter 6--Who’s Afraid of Reductionism? Confronting Darwin’s Dangerous Idea—is a 47-page account of his passage between the Scylla of common sense dualism and the Charybdis of a Darwinism-fronted material monism, a wonderfully drawn pilgrim’s progress. He begins with seven increasingly reductionist propositions you are invited to rate your comfort with. The final proposal, which is what he will defend and obviously subscribes to himself, is:

As products of a blind process of replication and selection, human beings as a whole—body and mind—differ only in degree of complexity from robots or machines: we, like everything in the world, are causally determined, purely physical systems.

How much comfort does Slingerland expect to bring us through his account of this philosophy? “If you are not disturbed and somewhat repelled, then I have not done an adequate job of explaining this material…” And what are we to assume from his even making the effort? “Thinking under this understanding, then, is not a ghostly, disembodied process, but rather a series of brain states—a series of physical configurations of matter—each causing the next in accordance.” In other words, the judgments through which he arrived at the opinions he so passionately defends involved no more weighing of options than the operation of the Krebs Cycle. How, in offering byproducts of his step in that cycle to his readers, can he expect them, probably at other steps around that cycle, to find his offerings nutritious?

He nowhere explains, as common sense demands, how a purely physical system can exercise judgment through the weighing of options and creativity through the generation of novelties. He merely declares it be so: “Human level meaning emerges organically out of the workings of the physical world, and we are being ‘reductive’ in a good way when we seek to understand how these lower-level processes allow the higher-level processes to take place.” Allow! Is that an explanation? “There are some very good reasons for this privileging of lower levels of explanations,” and for his illustration of these reasons he borrows from Daniel Dennett the operation of a computer game. All the common sense he uses in evaluating the merits of common sense desert him when he’s evaluating the merits of material monism. “Everything we know about how the world in general works suggests there is no place for nonphysical causation.” Really? Didn't his conscious experience while writing those words suggest a possible place for non-physical causation? He endorses the usual reassurance that we needn’t worry about being limited by determinism because the world is too complex for our futures to be elucidated. How, then, can he be so sure we are determined? If this is an untestable hypothesis it cannot be proved, and so is not science.

Darwinism clearly does seriously threaten traditional religious beliefs and conceptions of the self, he says. “We are convinced that Darwinism is the best account we have for explaining the world around us, and therefore that human beings are physical systems and the idea that there is a ‘ghost in the machine’ should be abandoned.”

The revelation that our nature, like our origin, involves only purely physical processes is beyond question. “Just as children come eventually to realize that there is no such thing as Santa Claus or the tooth fairy, so will dualist adults eventually grow up intellectually, realize the truth of physicalism, and come to see such songs and sentiments as childish wishful thinking—beautiful and once quite comforting, but not a proper component of a mature worldview.”

In other words, you're either of one temperament or the other, there can be no compromise. We can arrive at the truth only by voting. For an early preview of the outcome watch out for publication of papers from a conference organized by the National Humanities Center. Title: Creating Consilience: Integrating the Sciences and the Humanities. Editors: Mark Collard and Edward Slingerland.

Below, microdata:

Evolution for the Humanities
What Science Offers the Humanities evolution, humanities