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John Dupré, Human Nature and the Limits of Science: A Review

John Dupré was, at the time of this book’s writing, a philosopher of science at Stanford University (now at the University of Exeter) and was part of the so-called Stanford School of the philosophy of science. This book targets ‘imperialistic scientism,’ which Dupré defines as “the tendency for a successful scientific idea to be applied far beyond its original home, and generally with decreasing success the more its application is expanded” (16).


The thesis of the book, and I must say a welcome and appropriate warning to scientists, is as follows: “It is still common,” he says, “to conceive of genuinely scientific explanation as being necessarily mechanistic. That is to say, the task of science is seen as one of showing why things behave as they do by disclosing the way their constituent parts interact to produce that gross behavior…Mechanism, I take it, has proved wonderfully successful at addressing questions about how things work. But when it is taken beyond this limited, if important, role and inflated into a general metaphysical world view, it is disastrous.” (7)

I should note here that this book is written by one who does not believe in anything like immaterial substance, and therefore does not believe in a supernatural realm or ‘deities’ (5). He also does not believe in a designer, at least not for human beings, whom he says aren’t designed for anything or any purpose (175). So, this book is a critique of a particular kind of ‘scientism’ that comes from within the scientific community.

As a primary example of imperial scientism, Dupre cites the oft’ repeated claim that advances in particle theory (physics) and genetics (biology) have demonstrated that the world is entirely deterministic. Dupré challenges this claim by taking on the two central ‘completeness’ theses on which it rests: (1) the completeness of physics thesis (CPT) and (2) the causal completeness thesis (CCT).

Problems with the completeness of physics thesis

CPT assumes, Dupré observes, that the world is composed of, only and at bottom, ‘physical stuff’ (Dupré himself thinks this is true). Thus, it is thought, “the final physical story about the world’s ultimate constituents is, is some sense, the whole truth about the world” (5). A good many scientists hold to what he calls the thesis, or myth, of the centrality of the endogenous: “This is the thesis that we should always favour explanations in terms of the intrinsic, structural properties of thing over explanations that appeal to the influence of context or environment” (72). Combining, then, a physicalist understanding of the world with the centrality of the endogenous provides the premises for the conclusion that all explanations of world phenomena are to be found by reduction to base physical matter.

In the history of materialist philosophical and scientific thought, the phenomena of human behavior has remained a mysterious enigma—let alone human consciousness. Human behavior seems (to most of us, anyway) to be free, and not subject to the mechanistic laws of basic matter, at least not subject entirely to it. This is where, for the materialist, recent advances in particle theory and genetics seems to hold much promise of explanation.

Dupré considers, as an example, the human brain. Neuroscience, the hard science of the brain, has given much data for reflection in recent years. Combine this data with a general theory of evolution and the field of evolutionary psychology, formerly known as sociobiology, is born. The basic assumption in this field is that human behavior is controlled by the brain, which is itself composed of certain ‘physical modules’, which are the underlying cause of all human behavior. These modules, moreover, ‘must’ have developed evolutionarily during the Pleistocene era (the only pre-homo era long enough to account for all the genetic developments that would have had to occur) as advantageous to reproduction. Thus, all human behavior can be explained by appeal to advantageous reproductive traits, which are themselves explained primarily by physical brain modules, which are themselves explained by the material components that make up those brain modules and the laws which govern those component’s behavior. Or, so the story goes, quips Dupré.

In fact, Dupré argues, this story is woefully reductionistic. It fails in principle to explain the complexity of human behavior (55-69). In this case, advances in neurology and genetics—genuine advances which have elucidated a great deal concerning the relation of the human brain and human genes to human behavior—are forced to give a full and exhaustive explanation of human behavior; something these advances simply cannot do. According to Dupré, the world’s various and complex phenomena still cannot be accounted for by reduction to basic physical matter. CPT is simply false.

Problems with the causal completeness thesis

Second, he challenges CCT. By ‘causal completeness’ he means the view that “there [is] some quantitatively precise law governing the development of every situation.” What about the ‘situation’ of a human (or, more precisely, a seemingly free human)? Why might we be tempted to think of humans simply as complex machines, and thus governed by deterministic causes? Dupré argues that humans as complex machines seems plausible because we wrongly infer that machines could only work if the world were itself mechanistic. In other words, the fact that we can create machines that work with regularity requires a pre-condition of predictability, which itself can only happen if there are certain ‘laws’ governing certain physical entities and their interactions.

The problem, says Dupré, is that this picture is again far too reductionist (170-177). The very fact that machines malfunction and break down should give us pause. The fact is that machines only work by tightly constraining a very small and isolated set of physical data. “Reflection on how good machines are engineered, far from making us think of mechanism as generally characteristic of the world, should make us realize how difficult it is to turn even little bits of the world into bits of mechanism” (173). The most one can infer from this is that there are certain laws which govern certain physical entities and ensure a certain level of regularity in certain conditions. But this is very far from the ‘causal completeness’ that so many scientists want to affirm.

So, in the end he argues for causal incompleteness (163-170). And from the notion of causal incompleteness—in particular, that there are lots of different kinds of things (i.e. ‘metaphysical pluralism,’ cf. 182-83), some of which have a power of agency that is not the result of a previous causal chain but the beginning of a new set of causal events—he concludes that the “kind of narrowly focused scientific projects I have been examining look as philosophically misguided as they have proved empirically unrewarding” (183).

Dupré ends not by arguing that we won’t be able to give an adequate account of human behavior someday, but that such an account would have to be much more complex, not much simpler, as physical reductionism of any sort would have it.

I maintain, then, that an adequate view of ourselves, were we to acquire one, would include many parts. It would at least include an account of us as biological organisms with immensely complex functioning parts, and an account of how this functioning gave rise to some of the enormously complex capacities we often exhibit. It would require an account of how our societies function, as general as possible but no more general than the empirical facts permit, and an account of how aspects of social organization contribute to the endowment of human individuals with complex capacities that would be in principle beyond the reach of an isolated member of our species. It will include detailed accounts of some of the most important aspects of our social organization, such as economics, and of the history of our societies and our species. And at a philosophical level it will include an account of the nature and limits of our powers to act autonomously to create real change in the world. Or so I suppose. (183)

This queen is an incumbent

It turns out that perhaps science, in its restricted methodology, cannot (currently) account for the whole of the world, even if the world is only physical. Even if the world is only material, understanding it will require more than the hard sciences. Might this be a subtle call to the humanities? Might this be a hint that “science’s” self-understanding is beginning—just beginning—to acknowledge that perhaps it is not the ‘queen?’

Perhaps the promise held out by science, that it and it alone would be able to explain all, is now beginning to show itself for the false prophet it always was. Perhaps now science will learn to takes its place among the various fields of human inquiry—a place of esteem and honor no doubt, but merely one place among many. Perhaps the next generation will not have to deal with such naïve claims as those foisted upon the last century’s generations by those holding to the ideology of scientism, and so will be able to get on with the human project of seeking for truth. Perhaps. One can hope; or, rather, one should pray.

Joshua Schendel

Joshua Schendel

Joshua is professor of theology at Yellowstone Theological Institute in Bozeman, MT, where he lives with his wife, Bethanne, and their three kids.

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