“It is sad to say that a position such as that of C. S. Lewis is very similar to that of Rome. The “objective” authority which Lewis would substitute for the subjectivisms of pragmatic standards in ethics is not truly that of the God of Scripture. To seek an objective authority that various forms of paganism and Christianity have in common is to seek what does not exist. It is at the same time—and that is worse—virtually to level down the authority of the Creator and Judge to that of impersonal law. And impersonal law is an abstraction. The virtual result is a return to the autonomy of the individual man who interprets impersonal law for himself.” – Van Til from Chapter 11 of Christian Theistic Ethics
“If we keep this biblical notion of the knowledge of God before us, we shall think of human knowledge as analogical of God’s knowledge. And only if we do this can we have a truly Christian apologetic. Arminianism, with its salvation on the basis of foreseen faith, and Roman Catholicism, with its semi-Pelagian doctrine of human freedom, rest their thinking upon a false notion of divine knowledge. Accordingly, they are not able to offer an effective argument against idealist philosophy when it reduces the personal God to an abstract a priori principle which needs as its complement an equally ultimate a posteriori principle. This has become newly apparent in the writings of C. S. Lewis, C. Norman Bartlett, and John Thomas.” – Van Til from Chapter 18 of “An Introduction to Systematic Theology
“It is natural that Romanists should appeal to a general moral law recognized by unbelievers as well as believers. It is natural also that Arminians, like C. S. Lewis (Christian Behaviour, Broadcast Talks, etc.) should appeal to the “cardinal virtues” common to Christian and non-Christian alike. Over against their method the Reformed theologian should carefully point out that the Christian and the non-Christian systems of morality stand diametrically opposed to one another on the question of goal, of standard, and of motive power. This contention cannot be disproved by an appeal to Paul in Romans 2:14–15. It is true that every sinner knows he sins against God, as it is true that every sinner knows God (Rom 1:19–20). But this knowledge the unbeliever suppresses by means of his own principle of ethics. And this principle is exclusively immanentistic.” – Van Til from Chapter 4 of “An Introduction to Systematic Theology”
“This synthesis view is, as we have said, the view of Roman Catholicism. This is not to say that there are not many Protestants who also hold this or a similar view. As a rule non-Reformed Evangelicals, especially Arminians, also hold this type of position. Let me illustrate by referring to C. S. Lewis. “In all developed religions,” says Lewis, “we find three strands or elements, and in Christianity one more.” Here we already have the core of the matter. Christianity is said to be something additional to other points of view. There is, according to Lewis, a common goal and norm and motivation between Christians and the best of non-Christians. There are, to be sure, extreme non-Christian views for the interpretation of human life. These are held by pure subjectivists. But true objectivity is found where believers and non-believers together believe in the idea of the Numinous. When, according to Lewis, in The Wind and the Willows the Mole asks the Rat: “are you afraid,” and the rat, “his eyes shining with unutterable love,” answers, “Afraid? Of Him? O, never, never. And yet—and yet—O mole, I am afraid,” then the rat recognizes objective morality. When Galahad, in Malory’s Fasti, “began to tremble right hard when the deadly flesh began to behold spiritual things,” he did the same sort of thing that the writer of the Apocalypse did when he fell at the feet of the risen Christ “as one dead.”
The important point here is that for Lewis this idea of dread or of the numinous is not the sense of deity that is implanted in all men by virtue of their being the image bearers of God. Quite otherwise; this sense of the numinous is, for Lewis, an “interpretation” that man gives to the phenomena of nature. The unbeliever and the believer give the same interpretation to the facts of the universe that surrounds them so far as their recognition of something supernatural is concerned.
That there is for Lewis an area of common interpretation between Christians and non-Christians here, appears even more clearly when he goes further and says that all men “acknowledge some kind of morality.” All men are conscious of guilt, he says, because they recognize that they have done what they themselves admit, by virtue of this recognition of an objective “ought,” that they should not have done.
Still further, for Lewis there have been believers as well as unbelievers who have combined the numinous and morality, the two points already mentioned, and who then have tended to do what the Jews did so clearly when they “identified the awful Presence haunting the black mountain-tops and thunderclouds with the ‘righteous Lord’ who ‘loveth righteousness.’ ”
In these three points we have, for Lewis, “the long spiritual preparation of humanity” for the coming of that man who “claimed to be, or to be ‘one with’ the Something which is at once the awful haunter of nature and the giver of the moral law.” Van Til from Chapter 4 of “The Defense of the Faith”