Catholic Culture Trusted Commentary
Catholic Culture Trusted Commentary

The Fifth Way, Scientism, and Intelligent Design

by James D. Madden


This essay provides an interesting philosophical contribution to the question of causation in a scientistic worldview, suggesting that St. Thomas' theory of causality offers a more complete vindication of theism than intelligent design.

Larger Work

Faith & Reason


387 – 408

Publisher & Date

Christendom Educational Corporation, Front Royal, VA, Fall 2006

Vision Book Cover Prints

The popular press and academic journals have both recently made much of the "intelligent design controversy."1 Intelligent design has been proposed as a critique of the Darwinian naturalism that has a materialistic stranglehold on our educational institutions. Often this debate is presented as an "either / or" dilemma with Christian theism and intelligent design squarely on one side and atheistic materialism and Darwinism on the other. In what follows I will caution against this dichotomy. Although intelligent design may have some contribution to make to a case for rational theism, its ultimate apologetic value is very limited. Moreover, our discussion will show that the perennial resources of Thomism give us another way of approaching purpose in nature that is free of the particular limitations of intelligent design. The success or failure of intelligent design makes very little difference for the philosophical defense of Christian theism, since Thomism provides an independent and more comprehensive case. In what follows I begin with brief discussions of the primary theological claims that are typically defended in a teleological argument and why Darwinism poses a threat to these doctrines. Our discussion will then turn to the case for intelligent design along with a presentation of its limitations. Finally, we will consider the distinctive approach taken by St. Thomas Aquinas in his Fifth Way.

Two Tenets of Catholic Theology: Design and Providence

Catholic theology has always reserved an important role for the notions of purpose and design in our understanding of the relationship between God and His created order. As the Catechism of the Catholic Church puts it, following St. Paul's First Letter to the Romans: "starting from . . . the world's order and beauty, one can come to a knowledge of God as the origin and the end of the universe."2 This particular theological doctrine certainly contains the thesis that, as orthodox Christian theists have always maintained, the universe, or at least the natural substances that inhabit the universe, are designed. I call this claim the Design Thesis (DT). According to DT, the complex processes and organisms we find in nature are not merely accidental, but the products of divine artifice; they are designed in the same sense as we typically think of human artifacts as being designed.

The God of Christian theology is not a deistic watchmaker who crafts and creates the world, but who thereafter merely stands by and watches a perpetually functioning natural order. Rather, the Church has perennially taught that God not only designs and creates the world ex nihilo, but He also governs the world. The First Vatican Council reaffirmed this teaching succinctly in the following remarks from Dei Filius: "By his providence God protects and governs all things which he has made, 'reaching mightily from one end of the earth to the other, and ordering all things well.' For 'all are open and laid bare to his eyes,' (Wisdom 8:1) even those things which are yet to come into existence through the free action of creatures. (Hebrews 4:13)"3 I call this teaching the Providentialist Thesis (PT). The deistic, watchmaker conception of the creator is an impoverishment of the Christian theological tradition regarding the relation between God and creation.4 According to the proponent of PT, God is intelligently involved in every single event that transpires. God is not merely the designer, but also the executor of His plan for the universe (of course in doing so He does allow creatures to co-operate with him).

A Brief History of Naturalism

DT and PT have always been opposed by naturalism, a view that dates back in various forms at least as far as the pre-Socratic philosophers.5 By naturalism I mean the view that the entire order of creation can be accounted for by the blind impress of the laws of nature, the properties of matter, and even pure chance as depicted by natural scientific theories. A contemporary naturalist states the abiding first principle of naturalism as the claim that "Everything is a collection of entities of the sort the sciences are about, and all truth is determined ultimately by the truths about these basic scientific entities."6 That is to say, naturalists have always believed that what exists is reducible to matter (or at least whatever the most popular contemporary theory of matter might be), and all that happens is exhaustively explained by to the law — governed interactions of quantities of matter as described by the leading physical scientific theory of the day. Thus, there is typically no room in the naturalist's philosophy of nature for purpose, direction, design, or providence. The universe is merely a product of the combined work of natural causal necessity as expressed in quantifiable (even if only statistically probable) laws of nature and pure blind chance. It should be clear then that naturalism and the Christian dogma of design and providence cannot be affirmed all at once.

Stemming from Socrates's famous incredulity regarding the claim that blind mechanistic causes alone account for why he has decided to remain in prison in the Phaedo, there is a long tradition of anti-naturalistic arguments in Western philosophy articulated by such thinkers as St. Augustine, St. Thomas Aquinas, and others, which effectively made it unthinkable for one to conclude that that the vast complexity, order, and beauty of the natural world could be the product of anything but wisdom of infinite capacity.

Even the success of the emergent scientific method in the 17th century did not completely displace the default assumption that the complexity and order of the universe called for intelligent influence. For example, Robert Boyle was happy to embrace a form of semi-mechanism wherein material atoms, motion, and laws of nature are all that are needed to understand and predict natural phenomena. Nevertheless, Boyle also thought it unthinkable that a system of nature so intricate as that found in our universe is the product of blind material interaction. For example, Boyle makes the following claims:

By embracing the corpuscular or mechanical philosophy, I am far from supposing with the Epicureanism that atoms accidentally meeting in an infinite vacuum were able, of themselves, to produce a world and all its phenomena; nor do I suppose, when God had put into the whole mass of matter an invariable quantity of motion, he need do more to make the universe; the material parts being able, by their own unguided motions, to throw themselves into a regular system. The Philosophy I plead for reaches but to things purely corporeal; and distinguishing between the first origin of things and the subsequent course of nature, teaches that God indeed gave motion to matter.7

Boyle then goes on to give a design argument for God's existence very similar to William Paley's famous "watchmaker" argument for God's existence based on the analogy between sophisticated artifacts and complex biological systems. There were of course dissenters from this confidence in the presence of design and providence in nature, but these views were consistently on the intellectual fringe until rather recently.

With the publication of Darwin's Origin of the Species, however, the tables would begin to turn in favor of naturalism.8 Whereas for centuries prior there seemed nothing short of divine artifice could explain the order and complexity of even the simplest organisms, with the introduction of the theory of evolution by natural selection there was for the first time a putatively plausible means of explaining how organisms manifesting dazzling degrees of functional complexity could be derived from far simpler creatures without the influence of intelligent agency. What Darwin along with subsequent generations of biologists purport to show us is that pressures for survival, the occurrence of felicitous mutations, and the eons of time available since the first formation of life on earth are sufficient to explain the functional complexity of living things.9

The implications of the Darwinian revolution for the Christian dogma of design should be readily clear. If the occurrence of the wonders of nature can in principle be explained in terms of chance, natural law, and survival pressure, then it would seem that there is no justification for the claim that the hand of God can be seen to be at work in creation. Indeed, as the zoologist and popular apologist for naturalism, Richard Dawkins, has famously put it, Darwin's theory finally made it possible for one to be an intellectually fulfilled atheist.10

Before we move to a discussion of whether Dawkins's self-satisfied atheism is well placed, we need to stop to note the philosophical foundations of naturalism, primarily its implicit epistemology. Contemporary naturalism has as its theory of knowledge something that is unflatteringly known as "scientism," which basically amounts to the claim that the scientific method is the measure of all things. In other words, the proponent of scientism believes modern natural sciences provides the only method by which objective truth might be achieved, and therefore all claims to rational justification in theoretical matters must pass the scrutiny of the scientific method. Any purported truth claim that does not pass the scientific bar can at best be taken as a matter of non-rational faith.

It is not difficult to plumb the relation between scientism and naturalism; ones reason for being a naturalist is likely a prior commitment to scientism, even if unconscious or implicit. That is to say, what usually leads somebody to believe that only entities that are posited by well-confirmed scientific theories exist is the more deeply held view that the only means for obtaining knowledge is the scientific method. In the words of Fides et Ratio, scientism "refuses to admit the validity of forms of knowledge other than those of the positive sciences; and it relegates religious, theological, ethical, and aesthetic knowledge to the realm of mere fantasy."11 If all modes of knowing other than natural science are just so much superstitious fantasy, then it seems quite appropriate to rule any supernatural philosophical thesis or worldview out of court. Naturalism, under the assumption of scientism, is the only legitimate game in town. At the end of the day naturalism is really only a symptom of the deeper disorder, scientism, and it was Darwinism that gave scientism its modern impetus; for the theory of evolution by natural selection showed that it is in principle possible to account for bio-complexity within the resources of the scientific method, which previously seemed only explicable by divine artifice.

A New Challenge to Naturalism

The success of Darwinism is certainly a cornerstone of the naturalistic hegemony in Western universities. Nevertheless, some highly sophisticated and even scientifically trained thinkers have recently expressed dissent from the theory of evolution by natural selection. The work of William Dembski, Michael Denton, Stephen Meyer, Philip Johnson and others are the main sources of the recent critique of Darwinism, which often goes under the moniker of the Intelligent Design Movement.12 I will use Michael Behe, a biochemist who doubts whether Darwinian principles alone are sufficient to explain the complexity of life at its most fundamental levels, as an example of a figure at the forefront of this movement.

In his influential yet controversial book, Darwin's Black Box, Behe uses the example of a simple mousetrap to introduce the concept of irreducible complexity. A typical mousetrap is a system of five working parts arranged such that the absence of any one of the five pieces would undermine the capacity of the mousetrap to capture mice effectively.13 A mousetrap is irreducibly complex in the sense that it is "a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning."14 Thus, one would expect that a mousetrap could not have been formed through a gradual process of natural selection, for none of the pieces individually would increase the ability of the mousetrap to serve its function and there would therefore be no reason to select any of the parts unless the whole were already in place. If we were to encounter a naturally occurring mousetrap, we should then resist giving it an explanation in terms of Darwinian principles and instead suppose that it is the product of an intelligent designer.

Behe goes on to point out that nature is replete with irreducibly complex systems whose sophistication mocks the complexity of a simple contraption such as a mousetrap. For example, Behe offers a detailed discussion of the propulsion system (the flagellum) of a bacterium as one of a number of cases that call into question the viability of Darwinian explanation.15 The flagellum has hundreds of working parts, none of which serves any known purpose integral to the organism's survival distinct from its function within the flagellum. Yet each of these parts is necessary to the operation of the whole system. If Behe is correct, then none of the parts of the flagellum would have been preserved by natural selection, since none of them offers a survival advantage independently. Furthermore, the likelihood of all of the parts of the flagellum coming together by chance are so astronomically slim as to strain credulity. Thus, given that neither natural selection nor mere chance is a plausible explanation in this case, Behe concludes that the best explanation is "through the guidance of an intelligent designer."16 If Behe is correct, then Darwinism does very little to support naturalism and at the very basic biochemical level of nature divine artifice is ubiquitous.

The Limitations of Intelligent Design

Let us suppose that arguments offered by Behe and other members of the intelligent design movement are scientifically successful.17 Nevertheless, even under that assumption, there are still limitations inherent to the intelligent design program.

(1) Arguments such as Behe's do not give significant support to PT. Intelligent design may show that some agent has planned and possibly intervened in creation. However, this conclusion is equally consistent with deism. Christian theology calls for more than a cosmic artificer, but a divine governor whose constant intelligent participation in creation guides all occurrences. Intelligent design could play a role in an overall cumulative case for providence; where providence operates, we would likewise expect to find design, so intelligent design does partially confirm the providential hypothesis. Nevertheless, the results of intelligent design are also consistent with the absence of providence. Thus, if we are to defend the fullness of the Christian conception of God's relation to His creation, we must look beyond what intelligent design can in principle deliver. It would be too much to ask of a single argument that it answer all of our questions about the creator, so I take it that this worry alone is not enough to call intelligent design into to task for theological reasons. Of course even if intelligent design cannot overcome this limitation, it still may serve significantly as a naturalism defeater, although it alone will not get us to a robust Christian theism.

(2) Like any other scientific theory, no matter how strong the current scientific evidence in favor of the intelligent design hypothesis may be, its conclusions are still liable to revision or even wholesale rejection in light of future discovery. Should data be uncovered or theoretical adjustments be made to the basic Darwinian theory, the intelligent design hypothesis could be robbed of its explanatory value. Indeed, as I have noted above, there is already a growing body of scientific and philosophical literature that purports to explain apparent irreducible complexity in terms of Darwinian naturalism.18 Of course the mere proposal of alternative hypotheses and recognition of the fallible nature of all scientific theories do not themselves give us good reason to reject intelligent design; the fact of disagreement is never enough to reject a position out of hand. However, what the controversy does show is that any commitment to intelligent design as a means of supporting Christian theology must be tenuous. We simply must wait and see whether the intelligent design movement can defend itself in the scientific arena, and even if it can do so at the moment, our theistic belief will always be open to correction by the latest scientific research.

(3) Finally, in light of the close relationship between scientism and naturalism that we discussed above, we must proceed with caution with respect to intelligent design. Proponents of intelligent design argue that their results are the products of a rigorous application of scientific methodology, which could be reproduced by any fair-minded and competent scientist.19 The purported scientific respectability of intelligent design is part of what makes it such a stinging blow to naturalism, for it seems that the naturalist is being beaten at his own game. Given that the "design scientist" is engaged in a legitimate scientific enterprise, we are told that his or her results must be taken seriously. If design science is both successful and truly scientific, it would seem very difficult for the naturalist to resist its conclusions in light of his own scientism.

Nevertheless, this particular virtue may also be a vice. Notice that the proponent of intelligent design seeks to legitimate theistic belief by showing that theism can be proven to some high degree of certainty, given only the epistemic resources of scientism. I am certain that no proponent of intelligent design consciously holds such a belief, but I fear that this approach implicitly grants the naturalist's scientism. That is, by seeking to legitimate his project in scientific terms, the intelligent design proponent has in fact granted, though unintentionally, the naturalist's assumption of a modern empiricist conception of rationality. It would seem then that intelligent design and naturalism are really just two sides of the same coin; they both begin with the assumption (explicit or implicit) that science is the measure of all things and then attempt to defend a certain worldview on the grounds of what they believe the scientific method indicates. Of course many intelligent design proponents believe that design science opens the door to philosophy and theology that may go beyond the scientific method, but they nevertheless justify that openness only in scientific terms. The disagreement between intelligent design proponents and naturalists is over particular scientific results or what counts as a proper application of the scientific method, not over the scope of scientific explanation itself. Scientism with theistic results is still scientism.

What is the worry here? Why should we recoil from the idea of having a theistic philosophy and theology founded on a scientistic epistemology? There are two worries in play: (a) By implicitly granting scientism a failed design science would not only be insulting but injurious to the theist. That is to say, if we grant scientism as our understanding of rationality and intelligent design in principle fails as science, then it seems we have a very good argument against theism on our hands. (b) The apparent rational justification for and non-scientific status of theism is often grounds for limiting scientism in other areas of inquiry. The non-scientific nature of rational theistic belief would in fact show that there are more things in heaven and earth than are contained in the naturalist's philosophy, even if such supernatural truths are not provable in the terms the best confirmed scientific theories of the day. Part of what we need from a rational case in favor of Christian theology is an account of things that constrains the region of explanation we assign to positivistic, natural science. Failure to produce such a metaphysical theology runs the risk of leaving all of our inquiries tied to at least a methodological naturalism.

For these reasons we should take intelligent design to have very limited value to a rational case for Christian theism. What is needed then is, in the words of Fides et Ratio, "a philosophy of a genuinely metaphysical range, capable, that is, of transcending empirical data in order to attain something absolute, ultimate and foundational in its search for truth."20 A successful countering of scientism would give one good reason to believe that there are true philosophical and theological claims that do not need to pass the bar of scientific scrutiny — it would show that the scientific method does not exhaust the boundaries of rational thinking. Intelligent design may have some role to play in coming to such a position, but its role will be a greatly limited one.

St. Thomas Aquinas's Argument for Providence

We can find the resources for just such an anti-scientistic (though certainly not anti-scientific) argument in the perennial resources of the Thomistic tradition. St. Thomas Aquinas offers the classic statement of this approach in the text of his famous Fifth Way:

The fifth way is taken from the governance of the world. We see that things which lack knowledge, 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 they achieve their end not fortuitously, but designedly. Now whatever lacks knowledge cannot move towards and end, unless it be directed by some being endowed with knowledge and intelligence; as the arrow is directed by the archer. Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God.21

The first point to note is that the Fifth Way is not a design argument of the same sort we find in the tradition of Boyle, Paley, and Behe. St. Thomas is not concerned with explaining how complex collections of parts come to function as a teleological whole. If he were so concerned there would be no reason for him to limit his discussion to "things which lack knowledge," for intelligent beings are no better able to explain their functional complexity than are unintelligent agents.22 Rather, the Fifth Way gives us an argument that is supposed to prove God's existence, because it is only through his constant intelligent involvement in nature that the world is able to operate according to a certain set of observable laws of nature. In other words, the Fifth Way is directly an argument in support of PT.23

St. Thomas begins by noting that even those beings that lack the capacity to know, such as lower animals, plants, and simple material bodies, nevertheless follow stable patterns of activity, e.g., rocks always fall to the earth when released from a height. These patterns of movement and change are what we usually call "laws of nature." Moreover, the laws of nature contribute to the overall order and stability of the universe, i.e., the good of the universe. Such phenomena are not mere results of chance, for they happen in the same way constantly; by definition chance events are rare, and activities that follow the laws of nature are ubiquitous. Thus, the laws of nature must be grounded in the natures of the substances that follow these patterns,24 and substances with natures always act for ends or purposes, what St. Thomas calls a final cause.

We moderns who stand in the wake of a four-centuries old program to expunge the notion of formal and final causality from our conception of the natural world are likely uncomfortable with St. Thomas's insistence on the operation of purpose in nature. Many of us would prefer that we limit natural explanations either to efficient causes, i.e., the action of one substance (or event) upon another, material causes, i.e., the material constitution of substances, or some combination of these two principles. A comprehensive defense of the need for teleological causation to ground natural explanation goes well beyond what can be accomplished in the current essay.25 We can, however, get the flavor of St. Thomas's point by noting that he is appealing to the classical Aristotelian dictum that material and efficient causes are strictly insufficient to explain regularities in the natural order. St. Thomas makes this point in De Veritate, Q. 5, A. 2:

Material and efficient cause, as such, cause only the existence of their effects. They are not sufficient to produce goodness in them so that they be aptly disposed in themselves, so that they could continue to exist, and toward others so that they could help them. Heat, for example, of its very nature and of itself can break down other things, but this breaking down is good and helpful only if it happens up to a certain point in a certain way. Consequently, if we do not admit that there exist in nature causes other than heat and similar agents, we cannot reason why things happen in a good or orderly way.26

Aquinas's argument is that not only does the material universe follow law-like patterns of efficient causality, but those patterns are perfectly suited so as to produce a coherent system of nature that harbors processes conducive to the stable existence of living and non-living beings. The fact that the universe is so ordered is the fact that Aquinas believes calls for an explanation. We confront a universe that is not unlike a firearm that whenever dropped accidentally at a firing range always hits a bull's eye. The activity of this entity is both regular and felicitous (it always hits the target dead-center). It seems quite odd to conclude anything but an unseen intelligent influence in such cases; just as we would conclude that somehow the firearm is being aimed, we should likewise conclude that something is guiding the universe.27

Of course one might ask why ordered, efficient causation requires any kind of explanation. Somewhat paradoxically, David Hume, who is no friend of Aristotelian realism, provides us with an answer. Hume argued brilliantly that no description of a state of affairs in terms of the material properties of a substance and the efficient causal relations it seems to have had in the past implies that such a substance will be an efficient cause of any particular event in the future.28 As a Thomist might put it, if we disallow the notions of form and purpose as the ultimate determining factors in the activity of a substance and instead stick to the resources of an austere empiricism, we lose our ability to assign that substance the role of an efficient cause. Of course materialists and empiricist philosophers will disagree with the Thomistic claim that concepts of matter and efficient cause are insufficient to explain causality in general, but precious little progress has been made on the task of giving a empiricist, i.e., scientistic, account of causality since Hume wrote over two centuries ago.29 As Hillary Putnam puts it, "the notion of things causing other things is not a notion which is simply handed to us by physics."30 Thus, one is well within his rights to reject this long overdue promissory note and conclude that mechanism is a bankrupt theory of causation and St. Thomas's point that efficient causes are agents, and agents only act for ends. Thus, as St. Thomas puts, the final cause is the cause of the efficient cause.31 To deny efficient cause its end is to leave causality a mystery.

For St. Thomas, these considerations are sufficient to lead us to conclude that even unintelligent agents, inasmuch as they act by nature and as true causes, must act for ends. However, acting for an end requires knowledge of some kind; goals, purposes, ends, etc. are all objects of the intellect and require a mental life in the substances that act on them. Thus, those substances that lack the required epistemic capacities and yet act for ends must be directed in all of their activities by an external intelligence. As St. Thomas puts it, "What lacks intellect or knowledge, however, cannot tend directly toward an end. It can do this only if someone else's knowledge has established an end for it, and directs it to that end."32 Since natural bodies act for ends and lack knowledge, there then must be some intelligent being that exists and directs them to their end in the same way, to use Thomas's preferred simile, as an archer directs an arrow to a target.33

Now, the difference between St. Thomas's argument and the case made by intelligent design should be readily apparent. The Fifth Way is not a defense of DT directly; it is an attempt to support PT. The result of St. Thomas's reasoning is the conclusion that nature is constantly under the direction of an intelligence that guides every unintelligent substance through all of its movements and changes. In short, if the Fifth Way is successful, then Aquinas has shown that a very strong version of providence is actually the case. This is not to say, however, that Aquinas is opposed to the notion of design. Indeed, his strongly providentialist argument likewise implies design. If God directs and controls all natural events, then he ultimately directs and controls the events that led to the formation of complex organisms. St. Thomas, in short, is able to deliver both DT and PT.

Furthermore, notice that St. Thomas has not offered a scientific argument, and therefore his case is not subject to revision or rejection by future empirical or experimental results. The Fifth Way is a consequence of a broader metaphysical account of causation. One of the very basic concepts employed in physical science is law-governed efficient causality, and science offers no ultimate explanation of why such causality works as it does; it can only assume this notion and use it in less fundamental explanations. Any scientific explanation will presuppose efficient causality as a basic explanatory category, and will subsequently be unable to account for efficient causality. Therefore, since St. Thomas offers an explication of efficient causality, his position itself is not one open to scientific verification or revision. He is ultimately explaining what makes scientific investigation possible by showing the necessary conditions, including final causality, of one of the scientist's fundamental presuppositions.

The case of Darwinism is instructive on this point. We might expect a Darwinist to respond to the Fifth Way by arguing that evolution has done away with the need for final causes in biology by showing the all organisms are ultimately reducible to more fundamental biological units which are selected according to the dictates of external survival pressures. However, Thomas will simply respond by pointing out that any such reductionist account presupposes that there are efficient causal relations, and that such relations presuppose the operation of final causes. Thus, the Darwinian reductionist begs the question against St. Thomas, for he assumes exactly what has been called into question, namely efficient causal relations that are free from teleological influence.

Thomas's position is indeed indifferent to the success or failure of a Darwinian account of species formation, for what he is ultimately trying to account for is the continued occurrence of a natural order in which a process like Darwinian natural selection (which presupposes law-like relations of efficient causality) is even possible. The Fifth Way is then unassailable by Darwinian criticism, but it does not presuppose the scientific failure of Darwinism. Even if a complete account of the formation of organisms could be given in strictly Darwinian terms, the datum St. Thomas seeks to explain by God's intelligent influence, i.e., the law governed patterns of activity followed by unintelligent substances, would be left unaccounted for by such an account. Thus, Darwinism and the argument for providence are compatible.34

My appeal to a Darwinism-Thomism compatibilism is not a request for a facile truce or an advocacy of a "two truths doctrine" that trivialize the non-scientific account. St. Thomas's providential-teleological account is the more fundamental explanation of the workings of nature that encompasses and surpasses any naturalistic explanation by offering an explanation of its supposedly sui generus concepts, i.e., laws of nature and efficient causality. These considerations show us the great extent to which the Thomistic position is an antidote to scientism. The Fifth Way attempts to explain the possibility of scientific knowledge in non-scientific, metaphysical categories.

Whatever the cultural and apologetic virtues of intelligent design may be, and I have no doubt that it may yield great fruits, a theologically significant understanding of origins that addresses DT, PT, and avoids the perils of scientism, must begin with a more fundamental mode of explanation than that envisioned by the intelligent design movement. It is just this more fundamental perspective that is provided by the Thomistic tradition, and, given the call for such a metaphysics by Fides et Ratio, this should be the primary approach of the Catholic thinker. At the end of the day our advice to those troubled by the naturalism controversy is simply "Be not afraid." Whatever the scientific case may be, the explanation of science itself requires us to adopt a philosophy of nature that recognizes the omnipresent providence of the Creator. As Pope Benedict XVI has recently put it:

modern scientific reason . . . bears within itself a question which points beyond itself and beyond the possibilities of its methodology. Modern scientific reason quite simply has to accept the rational structure of matter and the correspondence between our spirit and the prevailing rational structures of nature as a given, on which its methodology has to be based. Yet the question why this has to be so is a real question, and one which has to be remanded by the natural sciences to other modes and planes of thought — to philosophy and theology.35


  1. Special thanks to Peter Pagan and Marie George for their very helpful criticisms of this paper at the 2005 meeting of the American Maritain Association. I have also found subsequent correspondence with Professor Pagan to be very helpful, as I have likewise been benefited by conversations with James S. Pappas.
  2. Catechism of the Catholic Church, 32. See also Romans 1:19-20.
  3. Cited in CCC, 303.
  4. For a detailed account of the rise of deism and its theological and moral consequences, see Taylor, Charles, Sources of the Self: The Making of the Modern Identity, (Cambridge, Massachusetts: Harvard University Press, 1989).
  5. The rhetoric of contemporary proponents of naturalism often implies that their view is the cutting edge product of the latest scientific and philosophical insights. However, naturalism is one of the oldest philosophical doctrines, and in fact it has changed very little over the centuries since its initial inception. For a critical history of naturalism, see Wiker, Benjamin, Moral Darwinism: How We Became Hedonists, (Downers Grove, Illinois: InterVarsity Press, 2002).
  6. Post, John, Metaphysics: A Contemporary Introduction, (New York: Paragon, 1991), p. 11.
  7. Boyle, Robert, "Of the Excellency and Grounds of the Corpuscular or Mechanical Hypothesis (1674), in The Scientific Background to Modern Philosophy, edited by Michael R. Matthews, (Indianapolis, IN: Hackett Publishing Company, 1989), p. 111ff.
  8. Today the most popular criticism of Boyle-Paley style, teleological arguments are derived from Darwin's theory of natural selection. However, David Hume had done much to call such arguments into question well before the introduction of Darwinian explanations of teleological complexity. For a discussion of Hume's basic criticisms of design argument and how the proponent of such an argument might reply, see Madden, James D., "Giving the Devil His Due: Teleological Arguments After Hume," in Post Humean Re-Assessments of Natural Theology, edited by James Sennett and Doug Grothius, (Downers Grove, Illinois: Intervarsity Press, 2005).
  9. See Ruse, Michael, Darwin and Design, (Cambridge, Mass: Harvard University Press, 2003) for a helpful overview of the history of Darwinian theory.
  10. Dawkins, Richard, The Blind Watchmaker, (New York: W. W. Norton and Company, 1996)
  11. John Paul II, Fides et Ratio: Encyclical Letter on Faith and Reason, (Strathfield: Saint Paul's Publications, 1998), Section 88.
  12. See Dembski, William, Intelligent Design, (Downers Grove, IL: InterVarsity Press, 1999), Denton, Michael, Darwinism: A Theory in Crisis, (Bethesda, MD: Adler and Adler, 1986). For a good summary of the views of the intelligent design movement in general, see Behe, Dembski, and Meyer, Science and Evidence for Design in the Universe, (San Francisco: Ignatius Press, 2000).
  13. Behe, Michael, Darwin's Black Box: The Biochemical Challenge to Evolution, (New York: Free Press, 1996), p. 42.
  14. Ibid., p. 39.
  15. Ibid., Chapter 3.
  16. Ibid., p. 96. It is important to note that Behe does not draw a theologically robust conclusion from his results. As Behe puts it, the "argument is limited to design itself; I strongly emphasize that it is not an argument for the existence of a benevolent God, as Paley's was," and "questions about whether the designer is omnipotent, or even especially competent, do not arise in my argument as they did in Paley's." (Behe, Michael, "The Modern Intelligent Design Hypothesis: Breaking Rules," Philosophia Christi, Series 2, Vol. 3, No. 1, pp. 165-166.) Behe does not claim that the God of orthodox theism can be derived directly from the evidence he cites in favor of design. All that he claims is that certain facts of biochemistry are sufficient to tip the evidential scale in favor of the design hypothesis. Whether the designer can be shown to be the unique, perfectly good, omnipotent and omniscient being worshiped by the Western religious traditions is a question that Behe is willing to leave to philosophers and theologians. Indeed, Behe is not alone in this interpretation of the implications of the contemporary argument for intelligent design. For example, William Dembski, the foremost figure in the intelligent design movement, explicitly claims that arguments such as Behe's are not works of natural theology. (See the "Introduction" to Demski's Intelligent Design.)
  17. The scientific success of intelligent design, along with its very status as a scientific theory, are hotly debated issues. For example, some biologists and philosophers argue that one may appeal to non-selection based processes, such as co-adaptation or genetic drift, in order to account for complexity without resorting to chance or design. For an accessible summary of these views and their critical relevance to Behe's argument, see Ruse, Michael, Can A Darwinian be a Christian: The Relationship between Science and Religion, (New York: Cambridge University Press, 2001) pp. 115-122. Since my goal is not to evaluate the scientific status of design arguments, I will leave this issue aside in what follows. I also direct the reader to Miller, Kenneth R. Finding Darwin's God: A Scientist's Search for Common Ground between God and Evolution (New York: Cliff Street Books, 1999) for further scientific objections to Behe's position. Behe's reply to Miller is found in "The Modern Intelligent Design Hypothesis: Breaking Rules," Philosophia Christi, Series 2, Vol. 3, No. 1, pp. 165-179. Ruse, Darwin and Design contains an assessment of the debate surrounding the intelligent design movement in light of philosophical, theological, and scientific considerations. For a discussion of whether intelligent agency is a strict implication of Behe's case, see Madden, James D., and Discher, Mark A., "What Intelligent Design Does Not Imply," Perspectives on Science and Christian Faith, December 2005, 286-291. Angus Menuge offers a sustained defense of intelligent design in light of much of the critical literature mentioned above in his Agents Under Fire: Materialism and the Rationality of Science, (New York: Rowman & Littlefield, 2004).
  18. References to some of the more accessible contributions to this literature are provided in footnote 20.
  19. As Benjamin Wiker, an apologist for the intelligent design movement, puts it succinctly, "Intelligent design seeks to show, through science, that natural things have been designed." Wiker, Benjamin, Moral Darwinism: How We Became Hedonists, (Downers Grove, Illinois: InterVarsity Press), 26.
  20. John Paul II, Fides et Ratio: Encyclical Letter on Faith and Reason, (Strathfield: Saint Paul's Publications, 1998), Section 83.
  21. St. Thomas Aquinas, Summa Theologica, Pt. I, Q. 2, A. 3. Translated by the Dominican Fathers.
  22. St. Thomas does, however, offer a design argument in Summa contra Gentiles I, c. 13. See Wippel, John, F., The Metaphysical Thought of St. Thomas Aquinas: From Finite Being to Uncreated Being, (Washington D.C.: Catholic University of America Press, 2000), pp. 418-441 for a discussion of this argument.
  23. St. Thomas in facts argues explicitly for providence using an argument very similar to the Fifth Way in De Veritate, Q. 5, A. 2.
  24. For an interesting and accessible scientific argument as to why laws of nature must be explained through the capacities of substances that behave according to such laws, see Barr, Stephen, Modern Physics and Ancient Faith, (Notre Dame, IN: Notre Dame Indiana, 2003), Ch. 11.
  25. For a comprehensive defense of teleological causation that follows the implications of such a theory throughout the philosophy of nature, the philosophy of mind, and ethics, see Koons, Robert, Realism Regained, (New York: Oxford University Press, 2000).
  26. Translated by Robert W. Mulligan, S.J., On Truth, Vol. I, (Chicago: Henry Regnery Company, 1952), p. 209-210.
  27. On my interpretation, Aquinas offers something akin (though not completely similar) to the fine-tuning arguments offered by those who take facts revealed by contemporary astrophysics to provide strong evidence in favor of God's existence. For a succinct example of a fine-tuning argument see Polkinghorne, John, "So Finely Tuned a Universe," Commonweal, August 16, 1996. Richard Swinburne offers an a contemporary argument from order that is partially inspired by St. Thomas's Fifth Way in Does God Exist? (Oxford University Press, 2001).
  28. See Hume's classics Enquiry Concerning Human Understanding, Sections 4-7 and Treatise on Human Nature, Part 3. David Pears provides a fair critical analysis of the classical Humean arguments in his Humes' System, (New York: Oxford University Press, 1990).
  29. See Fredrick Freddoso's introduction to his translation of Suarez's On Creation, Conservation, and Concurrence: Metaphysical Disputations 20-22 (South Bend, Indiana: St. Augustine's Press, 2002) for a critical discussion of recent neo-Humean attempts to account for efficient causality without teleology.
  30. Putnam, Hillary, Renewing Philosophy, (Cambridge, Mass: Harvard University Press, 1995), p. 50. See also Popper, The Self and its Brain, (New York: Routledge, 1984), pp. 204-205. Ric Machuga offers a very helpful discussion of this point in In Defense of the Soul: What it Means to be Human, (Grand Rapids, Michigan: Brazos Press, 2002), pp. 57-63.
  31. On the Principles of Nature, in Aquinas on Matter and Form and the Elements: A Translation of De Principiis Naturae and the De Mixtione Elementorium of St. Thomas Aquinas, translated by Robert Bobik, (Notre Dame, Indiana: University of Notre Dame Press, 1998), 37.
  32. De Veritate, Q. 5, A. 2. (p. 210 of Mulligan)
  33. There is a rather large literature on St. Thomas's argument for providence. See Wipple, The Metaphysical Thought of St. Thomas Aquinas, pp. 480-485; Fairacy, Robert, "The Establishment of the Basic Principle of the Fifth Way," New Scholasticism, vol. 31, pp. 189-207; Farell, Walter, A Companion to the Summa, (New York: Sheed and Ward, 1942); Garrigou-Lagrange, God, His Existence and His Nature, (St. Louis: Herder Publishing Co., 1936). A highly critical discussion of St. Thomas's defense of natural teleology can be found in Anthony Kenny's The Five Ways: St. Thomas Aquinas's Proofs of God's Existence, (London: Routledge and Keegan Paul; 1969).
  34. A bit of terminological care should be taken here. That is, by "Darwinism" I simply mean a philosophically innocent scientific project that attempts to account for contemporary diversity of species in terms of natural selection and scientifically chance mutations, i.e., those lacking a scientific explanation. This understanding of Darwinism would require its proponent to realize that scientific explanation is limited in scope and ultimately not self-certifying; scientific explanation always presupposes a foundation in a broader philosophical theory of causality. My view is that the success of Darwinism in this sense is compatible with a Thomistic philosophy of nature, especially in light of the fact that the latter explains the possibility of the former. However, if one means by "Darwinism" what more strictly goes by the moniker of "neo-Darwinism" or "evolutionary naturalism," there is no compatibility with Thomism. Darwinism in this sense is simply the claim that natural selection, chance, laws of nature, etc. provide a complete explanation of the complexity and diversity of contemporary organisms. Such a view is clearly incompatible with Thomism (or any form of Christian theism) and I hope that the argument of this paper in part shows it to employ a facile and naive understanding of the metaphysics of causal explanation.
  35. Pope Benedict XVI, "Faith, Reason and the University: Memories and Reflections," Aula Magna of the University of Regensburg, (Libreria Editrice Vaticana: 12 September 2006)

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