In his 1947 book Miracles, C S Lewis presents an argument against naturalism that has become one of the most influential philosophical arguments of its type of the last century. Very briefly, it says that under naturalism, mankind evolved purely by natural selection, for survival alone. His brain, therefore, could only (by the very tenets of materialistic evolutionary theory) be orientated towards survival, and not truth. There is no way then, under naturalism, that one could rely on human reason to discover truths about the world – including, of course, naturalism itself.
A couple of things to note for starters. Lewis wasn’t setting out to prove that reason plays us false, though other philosophers have shown how difficult it would be to demonstrate this is not so. Rather it is that since reason does, by comment consent, discover truth, materialistic naturalism’s only explanation for it must be false.
Consequently, Lewis throughout the rest of the book references human reason as an example of the “mundane supernatural,” partly to lessen objections to the concept of true miracles.
One materialist objection to this, that you’ll have seen before in relation to things like irreducible complexity or the origin of life, is that given time, science will probably be able to provide a full explanation of the evolution of the mind. But this, Lewis says, is irrelevant, and not only because it is based merely on wishful thinking, not evidence. For any such explanation would still require to be arrived at through human reason – and it is the very reliability of that which is in question.
It’s likely that Lewis didn’t originate this argument, for a similar one had been made long before by Arthur Balfour, of whom Lewis was an admirer. But although there were some weaknesses in Lewis’s original presentation (though fewer than in mine here!), many of which he corrected in subsequent editions, the general argument has not been refuted. Philosopher Victor Reppert, apart from writing an entire book developing several versions of the argument, continues to work on it. The fact that philosophers can build an entire career on arguments that bloggers like me state in three sentences ought to give some frequent commenters here pause for thought – and for deeper reading!
By framing Lewis’s argument in different ways, different points can be made, but there’s no space to go into that here. Perhaps the most thorough treatments of it in recent years have been by the Christian analytic philosopher Alvin Plantinga, who put it in its “final and official form” in the excellent Where the Conflict Really Lies. He sends casual readers glassy eyed by starting with the precept:
P(R/N&E) is low.
That’s easier to understand than it seems: in prose it states that the probability (P) that we have reliable cognitive faculties (R), given naturalism (N) and evolution (E), is pretty low. Just as Lewis said. Plantinga’s argument develops along the line that a materialist naturalist who admits the logic of this finds support for the reliability of his reasoning, but also a “defeater” for his naturalism. He ought therefore to reject naturalism.
One fact that adds strong weight to the argument from reason is that so many naturalists have, in various ways, themselves admitted its truth. Long before Arthur Balfour, Charles Darwin wrote to William Graham in 1881:
But then with me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?
Darwin’s point, in the context of the letter, seems to have been that even in old age he (sometimes) retained an inner conviction that the universe could not have arisen by chance, but uses the doubt about the reliability of evolved convictions to buttress his better, scientific judgement that the world is without purpose. The irony is that he irrationally exempts his scientific judgement from the strictures he places on his religious one. When he writes “I may be all astray” the inconsistency of his own words show he must be.*
But that inconsistency hasn’t stopped recent New Atheists from making exactly the same error in our own time. More than one has explained away religion as an arbitrary evolutionary development which, in some unspecified way, helped fitness whilst being totally untrue. The fact that this accusation applies equally to their own debunking of religion, and to their belief in evolutionary theory itself, escapes them. Lewis has words to say about that error, but I’ll leave those until the end.
Meanwhile, Lewis himself is able to quote his own opponent, the rationalist (and eugenicist) evolutionary biologist J B S Haldane, when he makes his own case:
If my mental processes are determined wholly by the motions of atoms in my brain, I have no reason for supposing my beliefs are true … and hence I have no reason for supposing my brain to be composed of atoms.
Irrefutable, isn’t it? And so as a philosophical argument, the argument from reason finds support, willing or unwitting, from all sides. And I suppose, since most Evolutionary Creationists have good things to say about C S Lewis, not many would want to be out of step with the world’s leading apologist, some of its best analytic philosophers, and mainstream evolutionists from Darwin through Haldane to Dawkins. The only real reason for disagreeing with it would seem to be hardline materialist convictions preferring logical incoherence to giving up naturalism.
But I said above that the argument has been put in various forms for different purposes. With Plantinga’s analytic formulae, we take it is a philosophical argument. It’s about a metaphysical system, naturalism, and its relationship to a philosophical concept, reason. What’s for the Christian not to like?
But I suggest it is quite possible, and also legitimate, to frame it as a scientific argument, since reason is axiomatic to the pursuit of science, so cannot be in doubt in that field. And evolution – as assumed in Lewis’s presentation to be a self-contained process of variation and natural selection – is a scientific theory of biology, no more and no less. And in essence, it’s the same theory now as it was in Lewis’s time, for under near-neutral theory, true reasoning is even less likely to arise than under adaptive natural selection.
In that case we would express the argument something like this: “Naturalistic (ie undirected) evolution has no mechanism giving more than a very low probability of producing an undoubted biological outcome, human reason. Therefore, naturalistic evolution should be rejected as a complete explanation of human biology.”
Now, practically speaking, any argument that disproves the adequacy of naturalistic Neo-Darwinian evolution for a major feature of human biology must affirm teleology, or in other words design. This is certainly how C S Lewis saw it, for having proceeded stepwise from the disproof of naturalism to Christian theism, he concludes:
[The human mind] is set free, in the measure required, from the huge nexus of non-rational causation; free from this to be determined by the truth known. And the preliminary processes within Nature which led up to this liberation, if there were any, were designed to do so. [my emphasis].
Follow his logic: the argument from reason counts very strongly against naturalistic evolution. The best alternative is design, even if evolutionary processes were involved. Theism is the best, or one of the best, explanations for the scientific evidence of a true reasoning faculty, and so divine design is the best explanation of observed human cognition.
Now, note that with very little adjustment, this reasoning applies as much to methodological naturalism, and to those forms of theistic evidence that deny divine activity may be demonstrated in science, as to hard metaphysical materialism. For then, the premise is “Evolution assumed methodologically to be naturalistic (God being hidden) has a low probability of producing human reason.” And the conclusion is: “Therefore this naturalistic form of evolution, and the methodology that leads to and supports it, should be abandoned.”
Lewis has a word to say about why this conclusion (and the evidence for God in nature) should be hidden from many scientists, and I find it agrees with what I’ve been saying for several years. Perhaps I retained it subsconsciously from my 1988 reading of Miracles:
There is thus a tendency in the study of Nature to make us forget the most obvious fact of all. And since the Sixteenth Century, when Science was born, the minds of men have been increasingly turned outward, to know Nature and to master her. They have been increasingly engaged on those specialised enquiries for which truncated thought is the correct method. It is therefore not in the least astonishing that they should have forgotten the evidence for the Supernatural. The deeply ingrained habit of truncated thought – what we call the “scientific” habit of mind [nowadays called “methodological naturalism” – Jon] – was indeed certain to lead to Naturalism, unless this tendency were continually corrected from some other source. But no other source was at hand, for during the same period men of science were coming to be metaphysically and theologically uneducated.
Well, I’ll vouche for the “metaphysically and theologically uneducated” bit after eight years at BioLogos.
So what response can the theistic evolutionist make to refute this conclusion and maintain that God’s work cannot be seen in nature? Well he can, I suppose, say that reason is the exception to the scientific rule, and is indeed beyond the reach of evolution, but maintain methodological naturalism in all other cases. In other words “This is our method, except when it suits us,” which is a nonsensical methodology. It would, however, be consistent with TEs’ habit of arbitrarily excluding the miracles of Christ from methodological naturalism, but only by allowing God’s activity one step nearer to the so-called “natural” realm.
Or secondly he can reject Lewis’s argument from reason altogether, despite its solid foundation, finding some ingenious theological motive for agreeing with the most irrational materialists. I’d be interested to hear that reasoning.
Or, perhaps, he could begin to explore what it is about human reason that places it beyond naturalism in the first place. Part of that involves C S Lewis’s own contention, drawn I guess partly from Aquinas’s observations on the nature of reason as well as Genesis, that the human being is a fusion of the biological and the spiritual – that to be human is to be partly supernatural. Consider the significance of this for that endless thread on BioLogos about the origin of man and human “bottlenecks”, all carried on “under the assumption of no miraculous intervention by God.” That assumption itself appears to be an instance of Lewis’s “truncated thought.” How can it be true if man’s major distinctive, his rationality, is supernatural?
But another thing for the TE to consider is whether the question might be partly that creation itself, and not just the creation of man’s reason, is beyond the natural. Once the metaphysics of naturalism fails, none of its conclusions can be taken on trust any more. What is this “Nature” so confidentally asserted to be operating without the direction of God?
* Incidentally, the end of this letter of Darwin’s is much less quoted, but is interesting in how Darwin defends the utility of natural selection for civilization against his correspondent:
Lastly I could show fight on natural selection having done and doing more for the progress of civilisation than you seem inclined to admit. Remember what risks the nations of Europe ran, not so many centuries ago of being overwhelmed by the Turks, and how ridiculous such an idea now is. The more civilised so-called Caucasian races have beaten the Turkish hollow in the struggle for existence. Looking to the world at no very distant date, what an endless number of the lower races will have been eliminated by the higher civilised races throughout the world.
“Evolution must be true because of ethnic cleansing” doesn’t seem quite so convincing an argument to us as it did to Darwin.