Callum Brown's remarkable book Becoming Atheist is an oral history of modern unbelief, based on interviews with eighty-five adult atheists across Europe and North America. It is impossible to read his account and deny that religiosity in the Western world has undergone an epochal shift during his interviewees' lifetimes.

Brown's people and their stories are enormously varied, but he observes that they share a remarkably consistent ethical code. That code has two key elements. First is the so-called "golden rule" of treating others as you would like to be treated. . . . The other is a linked set of principles about human equality and bodily and sexual autonomy. Brown calls this ethical framework "humanism". . . .

So where does this diffuse, ubiquitous ethic come from? If Brown's humanists did not even consciously adopt their ethics, how did they reach such a consistently shared position? Brown—a proud humanist himself—suggests that it may arise from "within human experience," indeed that "reason alone may construct humanism". . . . It is an appealing idea, but it is demonstrably false. Modern humanism is, perhaps unfortunately, in no sense an expression of universal human values. Its ethical markers—gender and racial equality, sexual freedom, a strong doctrine of individual human rights, a sharp distinction between the human and non-human realms—are, in a long historical perspective, very unusual indeed. Nor do they stand on a very firm logical base, as anyone who has ever tried philosophically to prove the existence of human rights knows. The fact that those values appear intuitively obvious to Brown, and indeed to me, is not an answer. It is the problem.

—Alec Ryrie
Unbelievers: An Emotional History of Doubt (2019)

—Pope Gregory I
(pope 590-604)

A deadly plague . . . is creeping into the very fibres of human society and leading it on to the verge of destruction. . . . We speak of that sect of men who, under various and almost barbarous names, are called socialists, communists, or nihilists, and who, spread over all the world, and bound together by the closest ties in a wicked confederacy, no longer seek the shelter of secret meetings, but, openly and boldly marching forth in the light of day, strive to bring to a head what they have long been planning—the overthrow of all civil society whatsoever. . . .

Although the socialists, stealing the very Gospel itself with a view to deceive more easily the unwary, have been accustomed to distort it so as to suit their own purposes, nevertheless so great is the difference between their depraved teachings and the most pure doctrine of Christ that none greater could exist.

—Pope Leo XIII
Quod Apostolici Muneris (1878)

For even if we recognize the powerful element of emotions and sentiments in politics, we can see that political ambitions are more or less rational ones, whereas this is less true of social ambitions, at the source of which we find the gnarled roots of Vanity, luxuriating in cavernous recesses of the human spirit; and it is therefore that the penetrating eye of the novelist may furnish some guidance here to the cultural historian.

—John Lukacs
Historical Consciousness (1968)

—D. Martyn Lloyd-Jones
Studies in the Sermon on the Mount (1971)

—G. K. Chesterton

It was a small matter that they [different sorts of men] reacted differently to that Will—grace—which flowed towards them from the primeval depths of existence. That one man accepted it, feelingly, intently, full of longing and affection, while others let themselves be carried along, resisting, yielding light-heartedly to every temptation, but still hanging on. He recognized, with a clearness that was almost intolerable, what the Church was—an organism with morbid and healthy cells animated by the same mysterious common life, either powerful or weak; but it made all the difference between life and death whether one took one's part or dropped out. It was the same difference as it makes in an army—of good soldiers and splendid soldiers and grousers and skulkers—whether one does one's duty or is already a deserter in one's inmost secret intention. It is the same as feeling solidarity with one's nation—the leaders, the common people, those who work and those who shirk—or planning one's flight to a foreign country, under an assumed name.

—Sigrid Undset
The Burning Bush, Book 3, chapter 4 (1932)