On Evolution & Intelligent Design

The fifth of St. Thomas Aquinas's "five ways" (quinque viæ) of proving God's existence is as follows:

The fifth way is taken from the governance of the world. We see that things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Hence it is plain that not fortuitously, but designedly [ex intentione], do they achieve their end. Now whatever lacks intelligence cannot move towards an end, unless it be directed by some being endowed with knowledge and intelligence; as the arrow is shot to its mark by the archer. Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God.

—Summa Theologica Iª q. 2 a. 3 co.

This is a teleological (Greek telos = "end") argument for God's existence because it argues that the whole world, its creatures—all created things—are directed toward an end; viz., they have a "final cause," to use the philosophical term. It, like Cardinal Schönborn's controversial essay "Finding Design in Nature," is "based neither on theology nor modern science nor ‘intelligent design theory.’"

In “Finding Design in Nature,” I said:

• The Church “proclaims that by the light of reason the human intellect can readily and clearly discern purpose and design in the natural world, including the world of living things.”
• “Any system of thought that denies or seeks to explain away the overwhelming evidence for design in biology is ideology, not science.”
• Quoting our late Holy Father John Paul II: “The evolution of living beings, of which science seeks to determine the stages and to discern the mechanism, presents an internal finality which arouses admiration. This finality, which directs beings in a direction for which they are not responsible or in charge, obliges one to suppose a Mind which is its inventor, its creator.”
• Again quoting John Paul II: “To all these indications of the existence of God the Creator, some oppose the power of chance or of the proper mechanisms of matter. To speak of chance for a universe which presents such a complex organization in its elements and such marvelous finality in its life would be equivalent to giving up the search for an explanation of the world as it appears to us. In fact, this would be equivalent to admitting effects without a cause. It would be to abdicate human intelligence, which would thus refuse to think and to seek a solution for its problems.”
• Quoting the Catechism: “Human intelligence is surely already capable of finding a response to the question of origins. The existence of God the Creator can be known with certainty through his works, by the light of human reason. . . . We believe that God created the world according to his wisdom. It is not the product of any necessity whatever, nor of blind fate or chance.”
• Referring to the Church's teaching on the importance and reach of metaphysics: “But in the modern era, the Catholic Church is in the odd position of standing in firm defense of reason as well. In the nineteenth century, the First Vatican Council taught a world newly enthralled by the ‘death of God' that by the use of reason alone mankind could come to know the reality of the Uncaused Cause, the First Mover, the God of the philosophers.”

My argument was based neither on theology nor modern science nor “intelligent design theory.” In theology, although the mind's ability to grasp the order and design in nature is adopted by, taken up into, and elevated to new heights by the faith of Christianity, that ability precedes faith, as Romans 1:19-20 makes clear. In science, the discipline and methods are such that design—more precisely, formal and final causes in natural beings—is purposefully excluded from its reductionist conception of nature. [...] [T]rue science is impossible unless we first grasp the reality of natures and essences, the intelligible principles of the natural world. We can with much profit study nature using the tools and techniques of modern science. But let us never forget, as some modern scientists have forgotten, that the study of reality via reductive methods leads to incomplete knowledge. To grasp reality as it is, we must return to our pre-scientific and post-scientific knowledge, the tacit knowledge that pervades science, the knowledge that, when critically examined and refined, we call philosophy. [...] First of all, we must observe that the role of randomness in Darwinian biology is quite different from its role in thermodynamics, quantum theory, and other natural sciences. In those sciences randomness captures our inability to predict or know the precise behavior of the parts of a system (or perhaps, in the case of the quantum world, some intrinsic properties of the system). But in all such cases the “random” behavior of parts is embedded in and constrained by a deeply mathematical and precise conceptual structure of the whole that makes the overall behavior of the system orderly and intelligible. [...] [T]he overwhelming trend of Catholic commentators on the question of neo-Darwinian evolution [...] gladly discuss[es] its compatibility with the truths of faith but seldom bother to discuss whether and how it is compatible with the truths of reason. [...] Let us return to the heart of the problem: positivism. Modern science first excludes a priori final and formal causes, then investigates nature under the reductive mode of mechanism (efficient and material causes), and then turns around to claim both final and formal causes are obviously unreal, and also that its mode of knowing the corporeal world takes priority over all other forms of human knowledge. Being mechanistic, modern science is also historicist: It argues that a complete description of the efficient and material causal history of an entity is a complete explanation of the entity itself—in other words, that an understanding of how something came to be is the same as understanding what it is. But Catholic thinking rejects the genetic fallacy applied to the natural world and contains instead a holistic understanding of reality based on all the faculties of reason and all the causes evident in nature—including the “vertical” causation of formality and finality.

—Cardinal Schönborn's "The Designs of Science"

There are two important ideas that the cardinal mentions: randomness and teleology. In the case of randomness, what appears to us as random is not necessarily so when understood more deeply, so randomness in nature is really an epistemological issue possibly due to Original Sin, our finite nature, and our imperfect intellects. E.g., the motions of atoms in a gas are not random in the sense that they obey no underlying rules; one can in principle derive the statistical properties of a gas by analyzing its trillions of atoms individually. Taken as a collection they have very predictable characteristics—e.g., temperature and entropy—indicative of an underlying logic. The same goes for quantum mechanics. The neo-Darwinists' biology, on the contrary, makes no predictions from random genetic mutations toward an increase in the information in DNA, which one would expect if more complex beings were to evolve from lesser complex ones, contrary to what the second law of thermodynamics says—that disorder tends to increase in closed systems. They call what they do not understand "random." Therefore, randomness in the former sense in no way precludes teleology as does randomness in the neo-Darwinists' sense. As for teleology:

Again, we should notice that, although every agent, both natural and voluntary, intends an end, still it does not follow that every agent knows the end or deliberates about the end. To know the end is necessary in those whose actions are not determined, but which may act for opposed ends as, for example, voluntary agents. Therefore it is necessary that these know the end by which they determine their actions. But in natural agents the actions are determined, hence it is not necessary to choose those things which are for the end. Avicenna gives the following example. A harpist does not have to deliberate about the strings that he will pluck, since these are already determined for him; otherwise there would be a delay between the notes which would cause uneveness. However, it seems more reasonable to attribute deliberation to a voluntary agent than to a natural agent. Thus it is plain, by reasoning a maiori, that, if a voluntary agent, for whom deliberation is more proper, sometimes does not deliberate, therefore neither does the natural agent. Therefore it is possible for the natural agent to intend the end without deliberation; and to intend this is nothing else than to have a natural inclination to something.

—St. Thomas Aquinas's Introduction to the Philosophy of Nature

The exclusion of final causes from science is a limitation because chance cannot be a cause:

It is necessary, no doubt, that the causes of what comes to pass by chance be indefinite; and that is why chance is supposed to belong to the class of the indefinite and to be inscrutable to man, and why it might be thought that, in a way, nothing occurs by chance. For all these statements are correct, as might be expected. Things do, in a way, occur by chance, for they occur accidentally and chance is an accidental cause. But it is not the cause without qualification of anything; for instance, a housebuilder is the cause of a house; accidentally, a fluteplayer may be so. [...] The question 'why', then, is answered by reference to the matter, to the form, and to the primary moving cause. For in respect of coming to be it is mostly in this last way that causes are investigated—'what comes to be after what? what was the primary agent or patient?' and so at each step of the series. [...] A difficulty presents itself: why should not nature work, not for the sake of something, nor because it is better so, but just as the sky rains, not in order to make the corn grow, but of necessity? (What is drawn up must cool, and what has been cooled must become water and descend, the result of this being that the corn grows.) Similarly if a man's crop is spoiled on the threshing-floor, the rain did not fall for the sake of this—in order that the crop might be spoiled—but that result just followed. Why then should it not be the same with the parts in nature, e.g. that our teeth should come up of necessity—the front teeth sharp, fitted for tearing, the molars broad and useful for grinding down the food—since they did not arise for this end, but it was merely a coincident result; and so with all other parts in which we suppose that there is purpose? Wherever then all the parts came about just what they would have been if they had come to be for an end, such things survived, being organized spontaneously in a fitting way; whereas those which grew otherwise perished and continue to perish, as Empedocles says his 'man-faced oxprogeny' did. Such are the arguments (and others of the kind) which may cause difficulty on this point [of teleology]. Yet it is impossible that this should be the true view. For teeth and all other natural things either invariably or for the most part come about in a given way; but of not one of the results of chance or spontaneity is this true. We do not ascribe to chance or mere coincidence the frequency of rain in winter, but frequent rain in summer we do; nor heat in summer but only if we have it in winter. If then, it is agreed that things are either the result of coincidence or for the sake of something, and these cannot be the result of coincidence or spontaneity, it follows that they must be for the sake of something; and that such things are all due to nature even the champions of the theory which is before us would agree. Therefore action for an end is present in things which come to be and are by nature.

—Aristotle's Physics 197a8-197a15; 198a33-198a35; 198b17-199a8

Addressing "I turned me to another thing, and I saw that under the sun, the race is not to the swift, nor the battle to the strong, nor bread to the wise, nor riches to the learned, nor favour to the skilful: but time and chance in all." (Eccles. 9:11), St. Thomas touches on what I called above randomness due to our imperfect intellects and lack of knowledge of all causes of things; i.e., that we are not able to perceive things perfectly holistically, atemporally, and omnisciently as can God:

These things are said to be under the sun which are generated and corrupted according to the sun's movement. In all such things we find chance: not that everything is casual which occurs in such things; but that in each one there is an element of chance. And the very fact that an element of chance is found in those things proves that they are subject to government of some kind. For unless corruptible things were governed by a higher being, they would tend to nothing definite, especially those which possess no kind of knowledge. So nothing would happen unintentionally; which constitutes the nature of chance. Wherefore to show how things happen by chance and yet according to the ordering of a higher cause, he does not say absolutely that he observes chance in all things, but "time and chance," that is to say, that defects may be found in these things according to some order of time.

—St. Thomas Aquinas's Summa Theologica Iª q. 103 a. 5 ad 1

Pope Pius XII's encyclical Humani Generis, the first papal document addressing evolution, sums up the Catholic position on evolution:

5. If anyone examines the state of affairs outside the Christian fold, he will easily discover the principle trends that not a few learned men are following. Some imprudently and indiscreetly hold that evolution, which has not been fully proved even in the domain of natural sciences, explains the origin of all things, and audaciously support the monistic and pantheistic opinion that the world is in continual evolution. Communists gladly subscribe to this opinion so that, when the souls of men have been deprived of every idea of a personal God, they may the more efficaciously defend and propagate their dialectical materialism. 6. Such fictitious tenets of evolution which repudiate all that is absolute, firm and immutable, have paved the way for the new erroneous philosophy which, rivaling idealism, immanentism and pragmatism, has assumed the name of existentialism, since it concerns itself only with existence of individual things and neglects all consideration of their immutable essences.

Hopefully science will free itself from some of its self-limiting practices, and, as Cardinal Schönborn says in his essay, "awaken Catholics from their dogmatic slumber about positivism in general and evolutionism in particular."