"You shall know the truth, and the truth shall make you odd." ~Flannery O'Connor

Friday, October 19, 2007

God and evolution: the state of the question

In the October issue of First Things, Cardinal Avery Dulles summarizes the God-and-evolution debate with his usual succinctness and authority. Though necessarily sparing us many details, he seems to me to have got the state of the question right. Given that he alludes to a book I reviewed earlier this year for that same periodical, I want to summarize the part of the summary that exhibits controversy among theists themselves, and to explain why I stand where I do on the question.

Dulles notes a fact with which any such summary must begin. What logically undergirds the arguments of the "new atheists" such as Dawkins, Harris, Dennett, and Stenger is not their knowledge of theology, which is rudimentary at best, or their passionate humanism, which is not entailed by the scientific facts. The crucial premise of their arguments against "religion" is what many (though not Dulles) have called "scientism": the belief that only what can be known scientifically can be known at all. As Dulles rightly says:

These writers generally agree in holding that evidence, understood in the scientific sense, is the only valid ground for belief. Science performs objective observations by eye and by instrument; it builds models or hypotheses to account for the observed phenomena. It then tests the hypotheses by deducing consequences and seeing whether they can be verified or falsified by experiment. All worldly phenomena are presumed to be explicable by reference to inner-­worldly bodies and forces. Unless God were a verifiable hypothesis tested by scientific method, they hold, there would be no ground for religious belief.

It is at the very least reasonable to question that epistemology philosophically, while accepting that genetic mutations that are "random" from an observational standpoint, and a process of natural selection that winnows them, occur as the mechanism of evolution. Thus:

....theistic evolutionism rejects the atheistic conclusions of Dawkins and his cohorts. The physical sciences, it maintains, are not the sole acceptable source of truth and certitude. Science has a real though limited competence. It can tell us a great deal about the processes that can be observed or controlled by the senses and by instruments, but it has no way of answering deeper questions involving reality as a whole. Far from being able to replace religion, it cannot begin to tell us what brought the world into existence, nor why the world exists, nor what our ultimate destiny is, nor how we should act in order to be the kind of persons we ought to be.

Theism is neither ruled out nor ruled in by the discoveries of natural science. It simply answers a different set of questions.

With that in mind, Dulles distinguishes three schools of thought among theists who accept that macroevolution has occurred at least partly through genetic mutation and natural selection.

The first is what he calls "theistic evolutionism" and is well exemplified by Francis Collins, who once headed the Genome Project, and last year published the influential book The Language of God:

Collins, a world-renowned expert on genetics and microbiology, was reared without any religious belief and became a Christian after finishing his education in chemistry, biology, and medicine. His professional knowledge in these fields convinced him that the beauty and symmetry of human genes and genomes strongly testifies in favor of a wise and loving Creator. But God, he believes, does not need to intervene in the process of bodily evolution. Collins holds for a theory of theistic evolutionism that he designates as the BioLogos position.

Although Collins is not a Catholic, he approvingly refers to the views of John Paul II on evolution in the 1996 message to the Pontifical Academy of Sciences. He builds on the work of the Anglican priest Arthur Peacock, who has written a book with the title Evolution: The Disguised Friend of Faith. He quotes with satisfaction the words of President Bill Clinton, who declared at a White House celebration of the Human Genome Project in June 2000: “Today we are learning the language in which God created life. We are gaining ever more awe for the complexity, the beauty, and the wonder of God’s most divine and sacred gift.”

Theistic evolutionism, like classical Darwinism, refrains from asserting any divine intervention in the process of evolution. It concedes that the emergence of living bodies, including the human, can be accounted for on the empirical level by random mutations and survival of the fittest.

I might as well lay my cards on the table now: Collins' "BioLogos" position, or what Dulles calls "theistic evolutionism," is my position. I'll abbreviate it as 'TE'.

A second, better-known school of thought is Intelligent-Design Theory (ID), best exemplified by Michael Behe, whose arguments are generally careful and technically detailed. ID theorists hold that

...certain organs of living beings are “irreducibly complex.” Their formation could not take place by small random mutations, because something that had only some but not all the features of the new organ would have no reason for existence and no advantage for survival. It would make no sense, for example, for the pupil of the eye to evolve if there were no retina to accompany it, and it would be nonsensical for there to be a retina with no pupil. As a showcase example of a complex organ all of whose parts are interdependent, Behe proposes the bacterial flagellum, a marvelous swimming device used by some bacteria.

...In favor of Behe and his school, we may say that the possibility of sudden major changes effected by a higher intelligence should not be antecedently ruled out. But we may take it as a sound principle that God does not intervene in the created order without necessity. If the production of organs such as the bacterial flagellum can be explained by the gradual accumulation of minor random variations, the Darwinist explanation should be preferred. As a matter of policy, it is imprudent to build one’s case for faith on what science has not yet explained, because tomorrow it may be able to explain what it cannot explain today. History teaches us that the “God of the gaps” often proves to be an illusion.

Dulles evidently shares my reserve about ID. The God of the gaps has a disappointing habit of retreating when the gaps are closed by the progress of science.

The third school of thought is the one least known outside scientific circles, yet also the most popular among professional theologians over the past century or so. It used to be called "vitalism" by philosophers, and is contemptuously dismissed under that name nowadays by the few scientists educated enough to be aware of it. Thus Dulles's description:

Darwinism is criticized by yet a third school of critics, one which includes philosophers such as Michael Polanyi, who build on the work of Henri Bergson and Teilhard de Chardin. Philosophers of this orientation, notwithstanding their mutual differences, agree that biological organisms cannot be understood by the laws of mechanics alone. The laws of biology, without in any way contradicting those of physics and chemistry, are more complex. The behavior of living organisms cannot be explained without taking into account their striving for life and growth. Plants, by reaching out for sunlight and nourishment, betray an intrinsic aspiration to live and grow. This internal finality makes them capable of success and failure in ways that stones and minerals are not. Because of the ontological gap that separates the living from the nonliving, the emergence of life cannot be accounted for on the basis of purely mechanical principles.

In tune with this school of thought, the English mathematical physicist John Polkinghorne holds that Darwinism is incapable of explaining why multicellular plants and animals arise when single cellular organisms seem to cope with the environment quite successfully. There must be in the universe a thrust toward higher and more-complex forms. The Georgetown professor John F. Haught, in a recent defense of the same point of view, notes that natural science achieves exact results by restricting itself to measurable phenomena, ignoring deeper questions about meaning and purpose. By its method, it filters out subjectivity, feeling, and striving, all of which are essential to a full theory of cognition. Materialistic Darwinism is incapable of explaining why the universe gives rise to subjectivity, feeling, and striving.

That is the viewpoint that Dulles professedly favors. Although I find much to sympathize with in such vitalism, I don't think it will quite do. In my review of Haught's book I gave a few reasons why. Here I want to expand on that a bit.

Citing the late Etienne Gilson's book From Aristotle to Darwin and Back Again, Dulles points out that modern science has rigorously excluded formal and final causality from its purview, admitting only "material" and "efficient" causes. Quite so. But the history of science teaches that there was a very good reason for that: only consideration of the latter two sorts of "causation"—a term better replaced by "explanation" in this context—allows for rigorous testing of hypotheses by experiment. Formal and final causality may well obtain, and on philosophical grounds I firmly believe they do. But it's too easy for certain theists to forget the reason they were excluded from scientific consideration in the 17th century, and it is quite arguable that science could not have made the progress it has if they had not been so excluded. I think it better to concede that what is nowadays understood as natural science should continue to leave them to the philosophers. That is not to say that formal and final causality are altogether irrelevant scientifically. Citing them can help answer legitimate questions that natural science, as that range of disciplines is understood today, cannot answer, such as the origin of "subjectivity" and "striving." That would place scientific findings about living beings in a fuller context, which would in turn help to illuminate such findings. But that fuller context is philosophical; it cannot replace natural science and should not be done instead of natural science—again, as that range of disciplines is understood today. Scientists as a class are not about to become Aristotelian natural philosophers, nor should they.

Now Dulles recognizes that all "three schools of thought are all sustainable in a Christian philosophy of nature." Nonetheless, the sort of objection Dulles raises against theistic evolutionism calls for a response. He says:

Several centuries ago, a group of philosophers known as Deists held the theory that God had created the universe and ceased at that point to have any further influence. Most Christians firmly disagreed, holding that God continues to act in history. In the course of centuries, he gave revelations to his prophets; he worked miracles; he sent his own Son to become a man; he raised Jesus from the dead. If God is so active in the supernatural order, producing effects that are publicly observable, it is difficult to rule out on principle all interventions in the process of evolution. Why should God be capable of creating the world from nothing but incapable of acting within the world he has made? The tendency today is to say that creation was not complete at the origins of the universe but continues as the universe develops in complexity.

Phillip E. Johnson, a leader in the Intelligent Design movement, has accused the Christian Darwinists of falling into an updated Deism, exiling God “to the shadowy realm before the Big Bang,” where he “must do nothing that might cause trouble between theists and scientific naturalists.”

The Catholic Church has consistently maintained that the human soul is not a product of any biological cause but is immediately created by God. This doctrine raises the question whether God is not necessarily involved in the fashioning of the human body, since the human body comes to be when the soul is infused. The advent of the human soul makes the body correlative with it and therefore human. Even though it may be difficult for the scientist to detect the point at which the evolving body passes from the anthropoid to the human, it would be absurd for a brute animal—say, a chimpanzee—to possess a body perfectly identical with the human.

Dulles' view may be summed up thus: he finds ID too dependent on a God of the gaps, and TE too deistic. Rather, and given the Church's irreformable teaching about the origin of the human soul, we should look to some form of vitalism as a viable option.

Having already explained why I don't think vitalism will do, I should say that I understand why Dulles favors it. It's much more satisfying theologically than TE. Even so, vitalism is a prescription for "a Christian philosophy of nature," not a prescription for natural science. I have no problem with that, so long as it is understood that developing a defensible Christian philosophy of nature is not the same as doing science. Since Dulles does not pretend to be doing science, I'm sure he would agree. Still, TE does seem a tad too deistic unless supplemented by such a philosophy of nature. So perhaps the key to reconciling vitalism and TE is establishing that what is "random" from the standpoint of material and efficient causes is anything but from a fuller explanatory standpoint that would include both Aristotle's four causes and natural theology.
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