From page 293 of The Narnian, by Alan Jacobs: talking about Lewis' reaction to Alec Vidler's radical theology and John Robinson's Honest to God:
But after all he had been through in Joy's illness and death, he better understood their discomfort with traditional doctrine. They were trying to get beyond "religion," and in his misery Lewis had come to understand that impulse - even if he thought they were going about it in absolutely the wrong way. "Religion" is either a set of cultural practices or a set of doctrines, and in either case - though for Lewis the doctrines were always absolutely necessary as maps toward one's true destination - they should never be the goal of the Christian life. (To make such a mistake would be "as if navigation were substituted for arrival, or battle for victory, or wooing for marriage.")
Beyond all religion lies Something, or rather Someone, that religion can never capture, Who is more real than any practices or doctrines. "We may ignore, but we can nowhere evade, the presence of God. The world is crowded with Him. He walks everywhere incognito. And the incognito is not always hard to penetrate. The real labour is to remember, to attend. In fact, to come awake. Still more, to remain awake." Such attention is difficult; we often fail to achieve it, and when we think we are most awake we are often sound asleep. One wonders how much of Lewis' own writing he believed, there near the end, to have been attentive in this true and full sense. It is perhaps telling that at one point in Letters to Malcolm he recalls what happened to Thomas Aquinas, who, after receiving an overwhelming and indeed disabling vision of God, thought back on his life's work of theological reflection and said, "It reminds me of straw."