There are numerous scientific challenges to Darwin’s theory. The Roman Catholic public intellectual and biographer of John Paul II, George Weigel has an essay in First Things on an article by the distinguished scientist, David Gelernter on Giving Up Darwin. Some years ago I wrote a review of Etienne Gilson’s book From Aristotle to Darwin and Back Again which included a reflection by Gilson on the dispute between French biologists and French mathematicians about the improbable probability statistics that would be necessary to make Darwin’s theory work. Gilson’s main critique was philosophical, with Aristotle he thought you couldn’t explain animals without teleology. It is becoming increasingly clear that Darwin’s theory works well for relatively small adaptive changes but fails as an explanation of the origin of species. Gilson said that natural selection was not an explanation but a placeholder for a lack of explanation. Below is my review of Gilson’s book.

Etienne Gilson, Translated by John Lyon. From Aristotle to Darwin and Back Again: A Journey in Final Causality, Species, and Evolution. Notre Dame, Indiana: Notre Dame Press, 1984. (Originally published in 1971 as D’Aristote a Darwin et retour. Librairie Philosophique J. Vrin) XX and 209 pages.

In order to help its readership make wise decisions about the allocation of precious reading time, a theological journal should alert its readers not only to promising new books but to existing books which are of enduring value, particularly if these books might otherwise escape notice. I have known the name Gilson for many years but have only recently become aware of his work on Darwin. Gilson was a distinguished French Thomist philosopher of the twentieth century who was a central figure in the renaissance of Catholic thought and culture in the years following World War II. He was invited to give both the Gifford lectures and the William James Lectures. He founded a famous center of Medieval Studies in Toronto which in turn produced a generation of scholars dedicated to retrieving the treasures of the Christian centuries. He lived into his nineties and wrote more than 600 titles. In his middle eighties, he decided to take on a philosophical analysis of Darwin’s Origin of Species, thus the title of this volume. The book is a magisterial treatment of the history of the interplay between the discipline of biology and the philosophy of science from Aristotle to Darwin and back again. Gilson carefully sorts out the dividing line between science and the philosophy of nature and the places where Darwin and others promote questionable philosophical conclusions that cannot properly be established by the scientific method as though they were the results of that method. If you look among the footnotes of contemporary critiques of the Darwinism of such writers as Richard Dawkins you will find numerous mentions of this book.

The hero of Gilson’s book is Aristotle. According to Gilson, in The History of Animals Aristotle identified the issues that have to be addressed in order to comprehend the existence of living things. In Gilson’s eyes, Darwin’s book is full of precise observations and shrewd generalizations but is not as adequate an analysis of the fundamental questions of biology as Aristotle. For Gilson Darwin describes many things and explains very little. To the extent that Darwin’s theory is frustrated in its explanatory power it is because Darwin resists Aristotle’s way of stating the problem.

For Aristotle living beings present a unique challenge to understanding. There are things that are made up of homogeneous parts and there are things that are made up of heterogeneous parts. Aristotle described four causes of things. These were the material, formal, the efficient and final. The material and efficient causes answer the questions of immediate causality, of how the thing works. The formal and final causes tell you what sort of thing it is and answer the question of why and what for. Homogeneous things, stones for instance, can be understood in terms of material and efficient causes but living things are different, says Aristotle; they can be understood only in light of their final cause. This is because really different sorts of things are in an organism organized in proportion and in favor of a principle and that principle is what the thing is for or its final cause. So for instance all the varied parts of the eye are organized to the purpose or end of seeing, which is the eye’s final cause, its telos. When we come to living things, Aristotle says, we come to the inescapable fact of the operation of final causes in nature. The end is present in the beginning. There is in nature teleology or the final causality in the title of the book. For Aristotle the perception of the proportion between an organism and its final cause was a source of contemplative joy.

Gilson relates the story of the mounting war against “finality” or teleology in the natural sciences. It takes a decisive turn with Descartes and Bacon. Both want to bracket the consideration of teleology and focus on the material and efficient cause because of the practical usefulness of this type of investigation. Focusing on the material and efficient cause, the how does it work questions, gives modern science its explanatory power and helps drive research toward technology. The desire to bracket the final cause turns in modernity into a campaign to develop a science which disproves the existence of teleology in nature. Darwin’s book is the decisive chapter in that campaign. His special interest was to disprove teleology in nature and especially that version of teleology based on the belief that God had created at the beginning of the creation all the species as they exist.

Gilson points out that Darwin does not actually undertake to explain the origin of species in his book. His book is really about how some species transform themselves into others over time. Darwin says that the process by which this happens is analogous to the process by which a breeder of livestock improves the breed or develops new varieties by selecting desired traits over time. The difference is that in what Darwin calls “natural selection” there is no final cause or teleology at work. The selection process is unconscious and advances by chance mutations which fit particular individuals to succeed especially well in the struggle for survival and who are thus able to reproduce in disproportionate numbers. By the accumulation of these very small changes brought about entirely by chance over very long times, new varieties or species emerge.

The problem is that it is very hard to see how this process can account for the complexity of organisms. Darwin himself was worried about how his theory could account for the complexity of the eye. The eye is made up, as Aristotle would say, of heterogeneous parts. The parts need to be organized to the end of seeing and it is very hard to imagine the small random steps that would lead suddenly to the emergence of a new organ. Gilson says some sort of final cause must be at work. In order to imagine a selection which is not driven by teleology Darwin invoked the “unconscious” selection made by a group of livestock breeders who do not set out to consciously develop a new breed but who do so unconsciously by simply preferring as a group the same sort of animals. Gilson points out that this is none the less an example of teleology and is an example of organization toward an end. Gilson argues that Darwin needs to make the selection process of the mythical livestock breeders unconscious so that he can make the same process in nature unconscious, the blind watchmaker of Richard Dawkins. So Gilson finds that Darwin cannot dispense with the final cause and in his attempt to evade the issue uses a metaphor that is simply a sort of crypto-teleology. Gilson believes that what drives this move in Darwin is not science but an attempt to discredit any kind of creationism by developing a biology without recourse to the consideration of teleology.  Gilson says that chance functions in Darwin’s system not as an explanation but as the place marker for the absence of explanation, an explanation that will not be forthcoming as long as teleology is deprived of its due weight. In addition Gilson finds Darwin giving himself over to the same kind of teleological contemplative joy that was known by Aristotle. Darwin is in awe of the fittingness of the adaptation of organisms to their environment. “Adaptation” is, according to Gilson, the word whose chief virtue is that it allows Darwin to enjoy the proportion between an organism and its final cause, all the while denying the existence of the thing he is enjoying.

 Reviewing theorists in contemporary theoretical biology that are grappling with the inadequacies of a purely mechanistic approach to biology, Gilson says “it brings to our attention the disturbing fact that the very existence of the biological is not susceptible of a mechanist explanation, and that, of course, not only insofar as it exists but insofar as it implies the existence of organized beings. . . . The facts that Aristotle’s biology wished to explain are still there. He is reproached, sometimes bitterly, with having explained them poorly, but to the present no one has explained them any better. Mechanist interpretations of these facts, which Aristotle formerly said had failed, have not ever been satisfactory; they have only displayed more and more the inevitability of the notions of organization and teleology invoked by Aristotle in order to explain the existence of mechanistic structures of which science is the study. Contemporary science itself attests to the unavoidable necessity of notions of this sort.” (p.119).

A little further on Gilson says, “We could say that, scientifically speaking, we ignore the question of why birds have wings, but to say that the conjunction of conditions necessary to the flight of birds was accidental is to say nothing. To add to chance the astronomical extent of billions of years during which it has been at work is still to say nothing, for whether the absence of a cause lasts a year or billions of years, it remains forever an absence of cause, which as such, can neither produce nor explain anything.” And finally from Gilson this coup de grace, “scientifically as well as philosophically, the mechanism of natural selection is simply a nonexplanation.” (131).

Gilson makes only modest and properly philosophical claims for teleology. The effects of final causality are observable in nature. The cause itself is not observable in the nature of the case. We observe the end at the end but we cannot make sense of other observations without postulating this final cause.  The final cause is, as Aristotle first observed, that which makes an organism an organism. The observation of these effects begs the question of the nature of the final cause. Proponents of intelligent design give one set of answers to this question which stands or falls on both the scientific and philosophical issues involved. Affirming final causality or teleology in nature does not automatically endorse any one philosophical or theological proposal about the true nature of the final cause. Gilson says that teleology is analogous to intelligence but that is all that can be said on the basis of observation itself. We cannot say without making further philosophical and theological moves that the final cause is an intelligence. The various sorts of creationism from young earth creationism to the episodic interventionism of intelligent design to theories which conceive of God directing the evolutionary process from within are all possible versions of final causality. Adjudicating between these claimants and other non-theological possibilities includes reference to the scientific record but requires philosophical and theological reflection as well.  Gilson makes the modest point that science cannot exclude the category of purpose from the explanation of reality a priori because science itself, especially as it attempts the comprehension of living things, bears testimony to the enduring necessity of final causality.    In this masterful book a philosopher in the tradition of Aristotle and Thomas Aquinas with a sure grasp of contemporary biology rings the front doorbell of an over-reaching, reductionist and mechanistic Darwinism and gives a better account of both the successes and the persistent failures of this hugely influential theory than the Darwinists themselves are able to give, and in the process deconstructs the myth of the blind watchmaker and sets the question of purpose in the universe as a kind of stumbling block that can’t be avoided or easily dismissed. The book is a hard read but foundational to the conversation between science and theology and profoundly significant for the apologetic and evangelistic task in these Darwinian times.