From Aristotle to Darwin and Back Again: A Journey in Final Causality, Species and Evolution

By Etienne Gilson

Foreword by Christoph Cardinal Schönborn

Darwin’s theory of evolution remains controversial, even though most scientists, philosophers, and even theologians accept it, in some form, as an explanation for the variety of organisms. The controversy erupts when the theory is used to try to explain everything, including every aspect of human life, and to deny the role of a Creator or a purpose to life.

The overreaching of many scientists into matters beyond the self-imposed limits of scientific method is perhaps explained in part by the loss of two important ideas in modern thinking—final causality or purpose, and formal causality. Scientists understandably bracket the idea out of their scientific thinking because they seek explanations on the level of material and efficient causes only. Yet many of them wrongly conclude from their selective study of the world that final and formal causes do not exist at all and that they have no place in the rational study of life. Likewise, many erroneously assume that philosophy cannot draw upon scientific findings, in light of final and formal causality, to better understand the world and man.

The great philosopher and historian of philosophy, Étienne Gilson, sets out to show that final causality or purposiveness and formal causality are principles for those who think hard and carefully about the world, including the world of biology. Gilson insists that a completely rational understanding of organisms and biological systems requires the philosophical notion of teleology, the idea that certain kinds of things exist and have ends or purposes the fulfillment of which are linked to their natures—in other words, formal and final causes. His approach relies on philosophical reflection on the facts of science, not upon theology or an appeal to religious authorities such as the Church or the Bible.

“The object of the present essay is not to make of final causality a scientific notion, which it is not, but to show that it is a philosophical inevitability and, consequently, a constant of biophilosophy, or philosophy of life. It is not, then, a question of theology. If there is teleology in nature, the theologian has the right to rely on this fact in order to draw from it the consequences which, in his eyes, proceed from it concerning the existence of God. But the existence of teleology in the universe is the object of a properly philosophical reflection, which has no other goal than to confirm or invalidate the reality of it. The present work will be concerned with nothing else: reason interpreting sensible experience—does it or does it not conclude to the existence of teleology in nature?”
—Étienne Gilson

• Language: English
• Publisher: Ignatius Press
• Release date: Sep 28, 2009
• ISBN: 9781681491950

Book preview

Foreword

Christoph Cardinal Schönborn

Mechanism, Scientism, Teleology and Evolution

There are two questions that loom large in the re-appraisal of modern science. Neither directly addresses the current debate about the idea of design or the adequacy of neo-Darwinian evolutionary theory. Yet they are decisive for our understanding of what evolutionary theory does or can explain in principle.

In this marvelous book by Étienne Gilson, these questions and other key topics are treated in a sensitive and illuminating fashion. Gilson, the great 20th-century commentator and historian of philosophy, helps us to see that reductionist accounts of evolution are the visible part of an intellectual iceberg, and that the issues that lie under the surface of the current evolution debate are ultimately far larger and more important. They extend to our understanding of nature and of modern science quite broadly, and to the intellectual culture that gave rise to modernity.

Two Questions

The first question is about the truth of mechanism, the dominant form of reductionism in science. While no one can question the methodological value of treating natural things as if they were nothing but an agglomeration of simpler parts all the way down, and then seeking an understanding of the parts and how they interoperate to cause the operations of the whole, the ontological question remains, and grows more and more urgent by the day: Is a stable natural whole—whether atom, or molecule, or bio-chemical, or cell, or plant, or animal—truly nothing but an arbitrary combination of indifferent parts? In other words, is it not really a whole at all, but only a label we give to a relatively stable interaction of parts? Even phrasing the question that way raises another: If so, why are only certain interactions of parts stable in the first place?

The second pressing question is the truth of scientism, the (usually) implicit philosophical claim that modern science provides the best or even the only valid answers to the questions raised by human reason as it considers the world around us. Science, according to this view, has rightly earned a privileged status in public discourse. The weak version of scientism, almost universally accepted today, is that science is the preferred, perhaps only valid way of really knowing anything about the material world around us: the cosmos; the stars and planets; our Earth and its seemingly unique biosphere; the animals, plants, minerals, and their evolutionary history. The only limit to this version of scientism is human nature itself, and even then only the supposedly spiritual or mental as opposed to bodily aspects of human life. These supposedly immaterial aspects of human nature are claimed to be exempt from the encroachments of science, a fortress-garden wherein notions of values, ethics, and religion are claimed to be able to flourish. The strong version of scientism, still widely contested but growing in strength in the modern West, ignores or abolishes the commonly accepted Cartesian mind—body boundary, and claims as for its future conquest everything about material reality, which is to say reality itself, including the historically conditioned, illusory, and now crumbling notions of spirit or mind in human existence.

The Historical Background: From Newton to Darwin

Those two questions—mechanism and reductionism on the one hand, and scientism on the other—are twins, entangled from birth in the scientific and philosophical revolutions of the 17th and 18th centuries. Those revolutions began in earnest with the philosophical and scientific speculations of the empiricist Bacon and the rationalist Descartes, in many ways so at odds with one another, yet sharing a profound unity in their condemnation of the Aristotelian-Scholastic tradition of formal and final causes, and their proclamation of the pressing need for the control and domination of nature through the study of its secrets in order to serve the comfort and bodily health of man. Galileo’s discoveries and speculations also help set the stage for change, in two respects. Positively, his astute decomposition and quantitative analysis of the laws of motion and his development and use of the telescope to show the unity of the sublunary and superlunary realms were of great scientific importance. Negatively, his polemic against geocentrism and simplistic biblical exegesis that was said to support it prepared the ground for more radical change.

Others provided much of the tinder for revolution, but it was Isaac Newton who set the fire blazing. The astounding triumph of Newton’s physics burned away the last strongholds of the medieval Aristotelian consensus about nature, confirming in the minds of Western elites the truth of the new instrumental science of Bacon and Descartes. By unifying celestial mechanics and terrestrial ballistics into a unified science of the motion of bodies, and providing a convincing set of reasons for the helio-centrism of Copernicus and Galileo over the empirically equivalent geocentrism of Tycho Brahe (as opposed to Galileo’s essentially aesthetic preference for conceptual simplicity), Newton not only decisively overthrew the Aristotelian cosmos and set the study of nature on an entirely new footing, but also brought into a tense but stable alliance the opposing intellectual poles of empiricism and rationalism under a particles and laws model of all physical reality. Newton’s corpuscularism (atoms, particles, bodies) represented the materialist, empiricist pole; and his mathematicism (laws) represented the rationalist, idealist, Pythagorean pole. These two opposing intellectual forces were yoked together in a new synthesis expected to reach and explain all of material reality! As he wrote in the Preface to the first edition of his Principia (1687):

Since the ancients (as we are told by Pappus) esteemed the science of mechanics of greatest importance in the investigation of natural things, and the moderns, rejecting substantial forms and occult qualities, have endeavored to subject the phenomena of nature to the laws of mathematics, I have in this treatise cultivated mathematics as far as it relates to philosophy. . . . I wish we could derive the rest of the phenomena of Nature by the same kind of reasoning from mechanical principles, for I am induced by many reasons to suspect that they may all depend upon certain forces by which the particles of bodies, by some causes hitherto unknown, are either mutually impelled toward one another and cohere in regular figures, or are repelled and recede from one another. These forces being unknown, philosophers have hitherto attempted the search of Nature in vain; but I hope the principles here laid down will afford some light either to this or some truer method of philosophy (emphasis added).

As Hans Jonas has pointed out,¹ it took a surprisingly long time—about 150 years—for the new science to provide any significant technological pay-back; medical and technological advances until the mid 1800s were almost entirely the result of practical, trial-and-error health care and engineering and not the result of the new science. But that delay had no impact on the intellectual tour de force of Newton and his followers, which swept away all pretenders. And the technological confirmation came eventually, in abundance.

Darwinism represents the final triumph of the Newtonian revolution, a particles and laws mode of explanation with an added element of chance to provide an entirely mechanistic solution to the problem of biological origins.² The genes are the particles, the law of natural selection (admittedly not very mathematical!) provides the necessity, and chance does the rest.

Newton himself, of course, championed the notion of divine design, and did not emphasize the question of origins or the role of chance, but in the intervening 150 years his disciples had swept away any direct role for divine causation and steady-state models and sought to explain the origin and development of natural systems using the same mechanical principles they had developed to explain their current observable states. The hypothesis of the nebular formation of the solar system and the science of geology, to give two examples, both explained complex natural phenomena by the interaction of chance initial conditions with deterministic physical laws resulting in the gradual emergence of natural things that had once been thought to be directly created. This new mode of explanation also reversed the classical notion that a cause must be greater than its effects. In the new science, lower and less-articulated things are by time, chance, and natural necessity the cause of higher and more-articulated things.

Before Darwin, biological reality seemed beyond the reach of the new science according to its preferred mode of explanation. With Darwin, the dominant Newtonian-Laplacian model of chance and necessity was at last brought to bear on biology and the origin of the diversity of living things. That fact alone helps explain the amazing speed at which evolutionism in some form swept aside all objections and became regnant in biological science within mere decades of the publication of The Origin of Species, where it remains to this day.

The Triumph of Scientism. . . and the Seeds of Its Undoing

In this familiar story of the triumph of modern science we see the twin ideas of mechanism and scientism emerging and beginning their domination of knowledge. As its mechanistic (particles and laws) model of explanation seemed to envelop more and more of reality within its grasp, and as the huge technological and material pay-out began in earnest, science became the only source of knowledge about reality that could not be gainsaid. Despite regular counter-reactions against an encroaching scientism—whether against the unweaving of the rainbow (Romanticism in the early 19th century) or the seeming meaninglessness of human life in a cosmos devoid of purpose (nihilism and existentialism in the late 19th and early 20th centuries)—every form of human knowledge and endeavor more and more adopted the particles and laws model of modern science as the paradigm of explanation and truth.

Where else could man turn other than to science? Theology, which in any case was privatized long before in the treaties known as Peace of Westphalia (1648) to stop the wars of believers against believers, is admittedly beyond human reason, and therefore not capable of providing a basis for public, increasingly secular and democratic knowledge. Philosophy too is not a source of real knowledge about reality inasmuch as every important philosopher disagrees with every other important philosopher about matters of the highest import. And common sense is obviously unreliable, as well, considering its many mistakes about the (non-)motion of the Earth, about spontaneous generation, about cell theory and germ theory, and a host of other scientific discoveries definitely beyond, and arguably contradictory to, everyday experience. So theology, philosophy, and common sense cannot guide us to truth. Only science remains.

Of all the modern sciences, Darwinian evolution and its various applications such as sociobiology have played an enormous role in the triumph of the scientistic worldview. Why? Because it is under the rubric of evolutionary theory that we find science’s answers to our most pressing questions: Where did we come from? What kinds of beings are we? What is our destiny? But, as we have seen, evolutionary theory triumphed largely as the result of the earlier, now-uncontroversial successes of mechanism and scientism.

And yet, in a deep irony, evolutionary theory may also contain the seed for the undoing of the scientistic, mechanical conception of reality. At the heart of modern evolutionary theory is the so-called struggle for existence. And the question gradually dawns on us: Why do living things struggle to survive? Why do they struggle at all? Neither rocks nor electrons appear to struggle to stay in their current configurations, nor do carbon atoms seek any obvious goals. What does it mean to struggle if not to seek an end? And if living things seek ends, then in what respect has old Aristotle been refuted when he claims that nature acts for an end? Allow me to quote on this theme the scientist, medical doctor, and philosopher Leon Kass:

Though there is today a growing debate about the mechanisms of evolution, the reigning orthodoxy still credits accidental mutation and natural selection as the major means of evolutionary change. Yet very few people have noticed that this nonteleological explanation of change not only assumes but even depends upon the immanent teleological character of all living organisms. The desire or tendency of living things to stay alive and their endeavor to reproduce, both of which are among the minimal conditions of Darwinian theory, are taken for granted and unexplained. It is only part of an explanation to say that those beings with no tendency to maintain and reproduce themselves have died out. Why are the other ones, the self-maintaining and reproducing beings, here at all? They are not teleological because they have survived; on the contrary, they have survived (in part) because they are teleological. Can evolutionary biology tell us why a nonteleological nature would generate and sustain teleological beings? Or why, over time, it would give rise to higher organisms, with a fuller range of powers of awareness, desire and action? Do we really understand what we are claiming when we accept the view that a mindless universe gave rise to mind?³

So, Darwinism is the triumph of mechanism, since it seems to bring within the sway of a universal, mechanical, particles, laws, and chance explanation that part of reality which seems to be most evidently not merely mechanical, that is, the world of living things. Yet, Darwinism is also unavoidably teleological—yes, a pared-down version of the older, grander claims of teleology, but teleological nonetheless.

From Aristotle to Darwin to Gilson

It is here in the heart of the problem of mechanism and scientism that Gilson takes up the tale. He begins with a limpid explanation of Aristotle’s allegedly anthropomorphic, non-mechanical view of nature, and helps the reader to see that one immediate need is to put aside the metaphysical question (who or what is the source of the ends that nature seeks) and recognize first the simple fact of nature acting for an end: Aristotle had a clear consciousness of the difficulty [of understanding how a non-intelligent thing like nature could act intelligently—that is, act for an end], but unlike certain of our contemporaries, a fact remained a fact for him even when he realized that he was incapable of explaining it (p. 11).

Gilson also points out that, rather than an anthropomorphic view of nature, it would be more accurate to say that Aristotle has a richly naturalistic view of man:

Let us elaborate this point a bit, for the true nature of Aristotle’s anthropomorphism, and consequently that of his finalism, are here involved. We say that Aristotle imagines nature as a sort of artist who deliberates and makes a choice among appropriate means toward the end which he proposes to himself. And such a scheme is true in a sense, as we come to view it. But it is still more true to say that in the last analysis Aristotle conceives the artist as a particular case of nature. That is why, in his natural philosophy, art imitates nature, rather than nature imitating art (pp. 12-13).

Man and his art are in effect a very special, concentrated, articulated case of a more general ability in nature. But what requires effort and learning to accomplish by art (art meant here very broadly, what we might today call technology) happens without effort or learning by nature. So, man is superior to other natural beings in that he has much greater mastery over both his ends and his means. But in another sense he is inferior to nature itself, for what nature does always or for the most part without effort and with great fittedness (we might say adaptation), elegance, and beauty, requires trial and error, effort, and learning when done by art.

Turning then to what he calls the mechanistic objection to Aristotle’s conception of nature, Gilson moves quickly to the key issue, clearly philosophical rather than scientific. If we follow Bacon and Descartes in defining science and knowledge in terms of what is useful, then only the how explanations of natural things, explanations in terms of material and efficient causes—the ways in which the parts operate to bring about an effect in or through the whole—will be seen as true knowledge.

We can manipulate and rearrange the parts of natural things to learn about their operation and possibly bring about desirable new results, but we cannot alter per se their forms or natural ends. Thus, our notion of what counts as knowledge, and ultimately what counts as natural reality itself, is largely determined by the decision to approach nature from the perspective of domination, control, and manipulation. As Gilson puts it:

We are not drifting away from our problem. We are at its center, for since the efficient cause is the only one that gives us a grip on nature, it is the only one worth knowing. Even if there were final causality, which Descartes denied but Bacon admitted, there is no place for it in a science whose end is to make us masters and possessor of nature. Final causality by its very nature is not susceptible of being refashioned. It is superfluous to say that birds are made for flying; that is obvious. But if anyone wishes to show how birds fly, we would be tempted to construct flying machines. If philosophy identifies true knowledge with useful knowledge, as modern scientism does, final causality will be by the same stroke eliminated from nature and from science as a useless fiction (p. 23).

Gilson has many other excellent insights. For example, he provides some rather pointed comments about the problematic notion of a theory that claims to explain the origin of species yet adopts a purely nominalistic doctrine that views living things as nothing but accidental variations within a continuous fitness landscape and that admits of no natural kinds. In other words, if there are no species, how can they have evolved or have an origin in the first place? He also points out that despite being confronted with a wide range of differing views on what evolution was supposed to mean, Darwin felt a basic affinity and unity with all those who denied the doctrine of the direct creation of species. In that sense, his life’s work was defined more by what it opposed than by what it affirmed.

The book is, however, not without weaknesses. Perhaps the most glaring is Gilson’s reticence about formal cause. At times he states that he need not defend it, and he implies that formality is harder to defend than finality. Yet at other times he appeals to form and to natural wholes and natural kinds, as he should: formality is ultimately unavoidable in any analysis of finality. The defense of formality is no more difficult than that of finality, as in natural things the two are irrevocably linked together. What kind of thing something is determines what its natural ends are; one cannot talk about natural ends without at least an implicit notion of natural kind, and form is simply the organizing principle or structure writ large that is the cause of that particular being of that kind. Indeed, one can argue that form is more evident than finality in much of nature as revealed by modern science. Specifically, the inanimate world studied by physics and chemistry is replete with structure and form, spoken of today in terms of emergence, natural kinds, and even elaborated by a school of thought in the philosophy of science that calls itself the new essentialism. Indeed, an entire branch of modern physics—solid state physics—has been founded and developed since about 1950 which unavoidably raises the issue of form and the ultimate irreducibility of stable natural structures into component parts. Finality, on the other hand, is harder to grasp in the inanimate world.

Perhaps Gilson’s greatest contribution to our understanding of the problem posed by the modern theory of evolution is his careful analysis of the relationship between Darwin’s relatively modest scientific theory of descent with modification, the much more bold evolutionary philosophy of Herbert Spencer, and the strange way in which the two were co-mingled in the lifetimes of the two very different thinkers. Darwin himself almost never used the term evolution; it appears nowhere in the first five editions of The Origin, making only a very modest appearance in the sixth. And yet others soon and universally imposed the word evolution on his theory, a word (as Gilson explains) with heavy teleological connotations. Spencer himself became bitter about the transference of his explicitly teleological—evolution as a kind of inherent tendency toward progress and ascendancy—and entirely philosophical writings onto the more modest scientific speculations of Darwin, with the result that Darwin’s scientific theory soon became the standard-bearer for the general notion of Spencer’s evolution.

Gilson argues that teleological concepts are implicitly imported into a supposedly non-teleological scientific theory largely as the result of the confusing and ill-defined word evolution.

The root of the difficulties is the fundamental indetermination of the notion of evolution. The notion signified something as long as it concerned the development of that which was supposedly enveloped, but Spencer popularized the word in another sense which no one could exactly define. Far from being the development of the enveloped, Spencer’s evolution is a prodigious system of epigenesis where each moment adds something new to the one preceding it. One is already in creative evolution or at least innovative and progressive evolution. But whereas one understood an evolution in which the less issued from the greater wherein it was contained, that form of evolution in which the greater continually springs from the less is incomprehensible. It at least deserves no more to be entitled e-volution. One is not speaking anymore, then, of the evolution of a germ which already contained a tree, but of the rumbling of an avalanche which has nothing constructive in it. Words have their importance. [The term] Evolution has above all served the purpose of hiding the absence of an idea. The word was initially used to convey the meaning that all had already been accomplished in advance and then came to be used to say that everything that happened was new (p. 103).

Or again:

Nothing is less like Darwin’s doctrine than the idea that new species should be already present in their ancestors, from which they only have to evolve in the course of time. Now, if the word evolution does not signify the contrary, or the inverse movement, from that of an in-volution, it does not signify anything intelligible. It is not certain that the present chaotic state of scientific evolutionism is not but the deferred effect of this original fault. Darwin at first avoided it. In a sense he was never personally responsible for it (p. 61).

I think there is an important insight here. The human mind can grasp only that which is intelligible. The development of a chain of living things in terms of some kind of unfolding or progress is certainly intelligible, by analogy to the development of any given complex organism from a simple seed or egg-cell. One might say (in reverse of the standard formulation) that the mind can readily grasp the idea that completely teleological phylogeny recapitulates ontogeny. But the meaning of absolutely directionless, meaningless, purposeless Darwinian change cannot really be grasped—there is no meaning in such an alleged process, and thus no intelligibility. Outside some kind of ordered framework (such as an existing population of well-ordered organisms seeking their own good), pure chance or disorder is not something the mind can really know. To make the point another way: chance and disorder are always understood negatively against a background of necessity and order. Humans constantly sneak in order and intelligibility by the use of ambiguous notions and concepts when attempting to think about allegedly non-ordered or chance-based events. Just as we tend to be blind to the perfectly ordered structure of the dice (balanced weight, size, density, etc.) when thinking of the chance events that we can generate with it—events which are random only because of the highly ordered and purposive nature of the dice—so too we are blind to the larger structure of intelligibility within the framework of scientific theories that depend on chance. For example, within evolutionary theory the standard interpretation ignores the goal-seeking nature of living things as they struggle to survive and reproduce, and the necessary fine-tuning of the environment and circumstances (such as gradual geographical separations of populations) that are prerequisites to the development of a new species according to standard speciation theory.

Gilson points to Darwin’s delight at Asa Gray’s essay which argued that his theory fit well with a classical understanding of teleology as intrinsic, immanent purposiveness. Perhaps if Darwin and his contemporaries had stood face to face with the richly naturalistic doctrine of Aristotle that nature acts for an end rather than the mechanistic, extrinsic, and theologically inadequate notion of design championed by William Paley, the resulting evolutionary ideas of the 19th century would have been quite different. We shall never know. But one can say that there is more affinity between evolutionary theory and the classical immanent teleology of Aristotle and St. Thomas Aquinas (although any direct assimilation is not without major difficulties) than there is between evolutionary theory and the deistic conception of God and the static conception of living things implicit in Paley’s mechanistic watchmaker arguments.

Beyond the "Self-Limitation of Reason"

Gilson’s illuminating discussion of Aristotle’s natural philosophy vis-à-vis Darwinism is of great importance in the modern debates about evolution. I know from firsthand experience how easily misunderstood are those who attempt to express a classical perspective on such matters. In my essay Finding Design in Nature in The New York Times of July 7, 2005, I wrote quite consciously from the classical philosophical perspective, while recognizing that many would misunderstand my meaning and see my writing as an endorsement of the scientific theory of intelligent design. That did not bother me in the least, since whatever its flaws, intelligent design theory is surely much closer to the truth about nature than the reductionistic account of evolution that it opposes. I must confess, however, that I was surprised just how few people seemed to have the philosophical background to understand what I actually wrote. I said nothing about specified complexity or irreducible complexity or other narrow, arduous, allegedly scientific concepts. I wrote instead: by the light of reason the human intellect can readily and clearly discern purpose and design in the natural world; I quoted His Holiness John Paul II on the internal finality of living things and of evolution, and wrote of metaphysics and the philosophical knowledge of the existence of God. Yet my philosophical discourse fell mostly on deaf ears. This excellent book by Gilson can help to open our ears once again to a specifically philosophical encounter with nature, which in turn opens the way for a sound theological encounter with modern science.

Philosophical engagement may be the most pressing need of our time. The world is full of people who believe in God, but is almost bereft of people who believe in the full power of human reason. In his famous Regensburg address in September 2006, our Holy Father Benedict XVI focused sharply on this issue. Just days after a private colloquium on evolutionary theory,⁴ he identified scientism as a major malady of the modern West and called for an end to this self-limitation of reason. He told the West that its encounter with other cultures, specifically with the growing power of Islam, would fail without a re-birth of philosophy, meaning the full play of human reason beyond the strictures of scientism. Sadly, this crucial message was lost in a firestorm of criticism aimed at a negative quotation about the limitation of reason within Islamic tradition, a quotation which only mirrored his stronger personal criticism of the scientistic West.

This timely republication of Gilson’s important book can help to dispel the self-limitation of reason. It is an accessible yet powerful antidote to scientism. It is my hope and prayer that a new generation will open their minds and hearts to a classically informed wisdom that can now be shared with a new generation of readers. We all have much to learn from Gilson about nature, Aristotle, Darwin, evolution, and the limits of modern science.

JULY 14, 2009

Preface

THE NOTION OF FINAL CAUSALITY has not been treated kindly. One of the principal reasons for the hostility toward it is its long association with the notions of a creator God and providence. Already in the Memorabilia, I, 4, 5-7, Xenophon attributed to Socrates the idea that the intelligence of man could only be