Originally posted at Standpoint.

Sixty years ago, C.S. Lewis delivered a hotly contested lecture at Cambridge University in which he identified “the Great Divide” that had seized the Western mind — and transformed it into something unrecognisable to earlier generations.

On November 29, 1954, in his inaugural lecture upon assuming the Chair of Medieval and Renaissance Literature, Lewis argued that the greatest cultural shift in the West was not its transition from the Middle Ages to the Renaissance, or from the pre-scientific to the scientific age. It was, rather, “the great religious change” in which Judaeo-Christian belief became unintelligible and unacceptable to most educated people: when the West became “post-Christian”.

Lewis was not the first to use the phrase, but he was among the first to realise the tectonic significance of the change in outlook. The “Christianising” of a pagan Roman Empire, seen as irreversible by our ancestors, was a radical development. But a post-Christian Europe — in which religious ideas about man’s nature and destiny were largely discarded — was even more radical. “Christians and Pagans had much more in common with each other than either has with a post-Christian,” Lewis said. “The gap between those who worship different gods is not so wide as that between those who worship and those who do not.”

The best of pagan thought, Lewis believed, anticipated the Jewish and Christian teachings about holiness, sacrifice and atonement. Thus Lewis chided contemporary Jeremiahs who warned that society was relapsing into paganism. “It might be fun if we were,” he quipped. “It would be pleasant to see some future prime minister trying to kill a large and lively milk-white bull in Westminster Hall.”

As Lewis saw it, the problem is that the post-Christian man is not only cut off from the Christian past but also from the pagan past. When confronted with “the idols of our own marketplace” — the assaults on human dignity from psychology, economics or science — he lacks the moral and spiritual resources to resist. The worst impulses of the materialistic and scientific mind are granted a free hand. “Its liberated presence in our midst,” Lewis warned, “will become one of the most important factors in everyone’s daily life.”

The catastrophe of the First World War had deepened the spiritual crisis in Europe in the post-war years. By the time Lewis launched his academic career at Oxford in the 1920s, the disintegration of orthodox Christian belief, which had begun in earnest in the 19th century, was almost complete. New ideologies arose in the exhaustion of the European democracies: Freudian psychology, eugenics, scientism, socialism, Communism and fascism. All began by promising liberation from oppression; all became instruments of the will to power.

Almost immediately after his conversion from atheism to Christianity, Lewis committed himself to combatting this cultural revolution. In works such as The Space Trilogy and The Chronicles of Narnia, his characters are invariably depicted as physical and spiritual beings, caught up before God in a great moral contest for their souls. This is as true for the most diminutive creatures in Lewis’s stories — including a mouse named Reepicheep — as it is for the human characters. “I know I am hardly worthy,” Reepicheep tells Aslan, the great Lion, “but with your permission I would lay down my sword for the joy of seeing your country.”

In his Cambridge lecture Lewis applied an academic objectivity to the post-Christian individual, noting only his psychological distance from centuries of Western thought. He playfully acknowledged that his lonely role as a “spokesman of Old Western Culture” was as alarming to himself as it might be to his audience. “Where I fail as a critic,” he said, “I may yet be useful as a specimen.” Yet everyone knew what Lewis believed about the folly of man without God: the secular delusions of human progress that had ravaged the 20th century.

Indeed, there is hardly a more wretched and horrifying character in science fiction than Lewis’s Professor Edward Weston, an eminent physicist on a quest for immortality. He becomes, almost inexorably, “the Un-man,” a negation of mankind’s moral and spiritual capacities. Weston serves as a warning against the “despair of objective truth” that had insinuated itself into the modern scientific mind. “Dreams of the far future destiny of man,” Lewis wrote, “were dragging up from its shallow and unquiet grave the old dream of Man as God.”

Sixty years on and the old dream has returned with a vengeance. I suspect that Lewis would implore us to shake the sleep from our own eyes, join the company of the wakeful and — no matter how unfashionable — get back into the fight.

Joseph Loconte is an Associate Professor of History at The King’s College in New York City and the author of the forthcoming A Hobbit, a Wardrobe, and a Great War: How J.R.R. Tolkien and C.S. Lewis Rediscovered Faith, Friendship, and Heroism in the Cataclysm of 1914-18 (Thomas Nelson, 2015)