Every so often, I'll hear or see a skeptic claim that religion is the result of non-thinking, a blind leap into the darkness of human ignorance. At the same time, he'll claim that his view of atheism is the view of science and truth, of reason and rationality. I find such people to be generally unaware of the most ironic thing about their position - if there is no God, there can be no such thing as reason and rationality. This is the Argument for God from Reason.
In one of his potent works, Miracles, C.S. Lewis offered this argument that has been popularly known as the argument for God from reason. Lewis contended that if nature is all that there is, then we cannot reason our way to rational conclusions. And if we cannot reason our way to rational conclusions, then we cannot reason that naturalism is true. Naturalism, as Lewis saw it at its bottom, is intrinsically self-contradictory.
What is Nature and What is Naturalism?
According to Lewis, "naturalism" is the view that "nothing exists except nature" with the word "nature" being "the whole show" or "whatever there is." IC.S. Lewis, Miracles, "The Cardinal Difficulty of Naturalism", 6.
"[What the naturalist believes] is that the ultimate Fact, the thing you can't get behind, is a vast process in space and time which is going on of its own accord." IIIbid., 7-8 (emphasis in original).
"The overarching process of the universe is materialistic" IIIIbid. 22. - everything in it is entirely physical or material. Though naturalism doesn't necessarily imply materialism, Lewis argued that a non-materialistic naturalism would not undermine his argument. Even in the event of an immaterial event occurring, though itself causally impotent, naturalism would entail that its cause must be material. As Lewis put it, Naturalism implies that,
"[a]ll the things and events [in the vast process] are so completely interlocked that not one of them can claim the slightest independence from 'the whole show'" IVIbid., 8.
The truth of naturalism implies that "every finite thing or event must be (in principle) explicable in terms of the Total System. I say 'explicable in principle' because of course we are not going to demand that naturalists, at any given moment, should have found the detailed explanation of every phenomenon." VIbid. 17.
If naturalism is true, "every thing and event would, if we knew enough, be explicable without remainder... as a necessary product of the system." VIIbid. 18 Thus,
"no thoroughgoing Naturalist believes in [libertarian] free will: for free will would mean that human beings have the power of independent action, the power of doing something more or other than what was involved by the total series of events." VIIIbid. 18.
On naturalism, miracles are impossible since they are by their nature outside of the material cause and effect relationship of the world, and there is "nothing outside to come in, Nature being everything." VIIIIbid. 15 Naturalism entails causal closure - every event, whether material or not, that has an explanation has only a material causal explanation. Material or physical causation is mechanistic, and mechanistic causes are fundamentally nonteleological - fundamentally purposeless. By now, I hope you're starting to see part of the problem - the choices we make when making inferences are indeed teleological.
Naturalism and the Problem of Human Reason
While not every cause is presently known or even knowable, what is an absolute must given naturalism, is that every causal explanation must be material in nature. Given the necessary corollaries of material causal explanations of everything within naturalism, we don't have any grounding for explaining how we can reason if reasoning is the sort of thing that happens as a matter of deterministic mechanistic causes.
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"Intro to Logic"
If we cannot reason and do not reason, then there is really no way for us to be able to reason that naturalism is true. Oddly, if naturalism is true, then we do not reason at all. If we do not reason, then we cannot also reason that naturalism is true. We cannot arrive at the conclusion that naturalism is true based on any sound reason. Lewis put it best,
"Any thing which professes to explain our reasoning fully without inducing an act of knowing thus solely determined by what is known, is really a theory that there is no reasoning.
But this, it seems to me, is what Naturalism is bound to do. It offers what professes to be a full account of our mental behaviour; but this account, on inspection, leaves no room for the acts of knowing or insight on which the whole value of our thinking, as a means to truth, depends.
It follows that no account of the universe can be true unless the account leaves it possible for our thinking to be real insight. A theory which explained everything else in the whole universe but which made it impossible to believe that our thinking was valid, would be out of court. For that theory would itself have been reached by thinking, and if thinking is not valid that theory would, of course, be itself demolished. It would have destroyed its own credentials. It would be an argument which proved that no argument was sound—a proof that there are no such things as proofs—which is nonsense." IXIbid. 21-2
Why Can't We Reason If Naturalism is True?
"Reasoning" is "the practice of inference." XIbid. 29 If naturalism is true, what we have thought to be our inferences are really not. XIIbid. 29 "Reasoning" is essentially a mental process. "Mental events" are events that are about something. "Acts of thinking are no doubt events; but they are a very special sort of events. They are "about" something other than themselves..." XIIIbid. 25. And they are not material or mechanistic. This is known in philosophy as "intentionality," and was discussed in one of William Lane Craig's debates with Alex Rosenberg.Losing the grounding for our ability to reason also compromises science. Click To Tweet
Losing the grounding for our ability to reason also compromises science. If we do not and cannot reason, we cannot do science. Indeed any and all activities pertaining to the activity of making inferences would be impossible to carry out. As Lewis put it, "Unless human reasoning is valid, no science can be true." XIIIIbid. Ibid. 21
However, we know that we reason. And since we reason, naturalism must be false. Reasoning (making inferences) violates the causal closure of the material world. Within naturalism, explanation of a mental event can include nothing other than what is material in nature.
As Lewis so aptly put it,
"One thought can cause another by...being seen to be...a ground for it… Any thing which professes to explain our reasoning fully without introducing an act of knowing thus solely determined by what is known, is really a theory that there is no reasoning." XIVIbid. 25, 27
If any material causal explanation depends on a mental causal explanation, the undeniable implication is that mechanistic causal closure is false. It is then one of the ironies of the ages, that while some claim to be the enlightened few who have seen the truth and have reason and rationality on their side, such a position cannot be warranted simply because it is impossible within naturalism.If any material causal explanation depends on a mental causal explanation, the undeniable implication is that mechanistic causal closure is false. Click To Tweet
The eminent philosopher, Alvin Plantinga, also has a form of an argument for God from reason XVAlvin Plantinga, Where the Conflict Really Lies: Science, Religion, and Naturalism (New York: Oxford University Press, 2011), chap. 10.. For more details of this argument from Lewis, please see Miracles and read the wonderful essay by Stewart Goetz in Philosophia Christi. XVIStewart Goetz, Philosophia Christi, Vol. 15, November 1, 2013, "Neuroscience and the Soul: Philosophical Issues," "The Argument from Reason", Evangelical Philosophical Society
|↵I||C.S. Lewis, Miracles, "The Cardinal Difficulty of Naturalism", 6.|
|↵II||Ibid., 7-8 (emphasis in original).|
|↵X, ↵XI||Ibid. 29|
|↵XIII||Ibid. Ibid. 21|
|↵XIV||Ibid. 25, 27|
|↵XV||Alvin Plantinga, Where the Conflict Really Lies: Science, Religion, and Naturalism (New York: Oxford University Press, 2011), chap. 10.|
|↵XVI||Stewart Goetz, Philosophia Christi, Vol. 15, November 1, 2013, "Neuroscience and the Soul: Philosophical Issues," "The Argument from Reason", Evangelical Philosophical Society|