The decline of the prestige of Christianity raises the question of what will replace it. No culture can live without a philosophy which gives structure and meaning to social institutions and to individual lives. The alternative is nihilism, whose wintry bleakness makes it an unwelcome guest at the dinner table.

So what, then?

One answer comes from Pope Francis. Ever since he was elected in 2013, he has fingered two ancient Christian heresies, Gnosticism and Pelagianism. They figured in his first solo encyclical, Evangelii Gaudium, and he often mentioned them in passing in other talks. Ism-talk tends to make people dizzy, so these ideas needed to be unpacked. Which is what happened earlier this year when theologians in the Congregation for the Doctrine of the Faith published a document called Placuit Deo which highlighted their danger for Christian life.

But, as if the Pope couldn’t wait for this to sink in, he included a long section on Gnosticism and Pelagianism in his latest document on the idea of Christian holiness, Gaudete et Exsultate. He describes them as self-centred, elitist and sinister.

The selection of these two mindsets or ideologies is an idiosyncratic brainwave on the part of Pope Francis. But they do seem to represent perennial trends in the intellectual history of Western culture — historical reflux bringing up the bitter taste of past projects for a post-Christian world. He has created an interesting framework for understanding our own times – and our own lives – as society becomes more and more secular.

Let’s take Gnosticism first. The key notion of Gnosticism is opposition between spirit and matter. Its origins may stretch back to the ancient Persian religion, Zorastrianism, but the Greek philosopher Plato created an intellectual framework for it. Plato was by no means a Gnostic, but he taught that true knowledge was spiritual, and that attaining the truth requires us to purify it of matter. Of course this is correct, with many provisos, but the characteristic note of popular Gnosticism was to hold matter in contempt.

This immediately set it at odds with Christianity. For Jesus of Nazareth, although worshipped as the divine Son of God, was also truly a man, with human flesh. He felt hunger and thirst; he wept, rejoiced, and felt dread and fear; he suffered and died. This was an absolutely central doctrine for the early Christians. But influenced by pagan Gnosticism, early Christian heresies tried to explain this paradox away by arguing that the humanity of Christ was not real — just drapery concealing his divinity. In other words, they rationalised the plain evidence of the New Testament. They had their own secret key to the Scriptures.

Claiming to possess deep insights hidden from the common man was a characteristic feature of the early Gnostics. One of the great early Christian bishops, Irenaeus of Lyons (130-202), hammered them mercilessly in his 2nd Century treatise Adversus haereses (Against heresies):

“As soon as a man has been won over to their way of salvation, he becomes so puffed up with conceit and self-importance that he imagines himself to be no longer in heaven or on earth, but to have already passed into the fullness of God’s powers. “With the majestic air of a cock he goes strutting about, as if he had already embraced his angel.”

What Irenaeus detected, too, was that disdain for matter leads to two very different conclusions: extreme asceticism and extreme libertinism. The former was the fundamental reason why the Church of the Middle Ages took a later Gnostic movement so seriously, the Albigensians. Since they believed that the liberation of the soul from the body was essential for salvation, Albigensians condemned marriage and condoned ritual suicide by starvation, amongst other bizarre doctrines. Had the movement survived, the population of Europe would be considerably smaller.

You might think that such ideas died in the crusades launched against Albigensian strongholds in southern France in the early 13th century. But Pope Francis is convinced that they have been revived in our own time.

Gnosticism is one of the most sinister ideologies because, while unduly exalting knowledge or a specific experience, it considers its own vision of reality to be perfect. Thus, perhaps without even realizing it, this ideology feeds on itself and becomes even more myopic. It can become all the more illusory when it masks itself as a disembodied spirituality. For gnosticism “by its very nature seeks to domesticate the mystery”, whether the mystery of God and his grace, or the mystery of others’ lives.

The Pope’s concern is, of course, largely theological and pastoral. But there are strands of latter-day Gnosticism everywhere in contemporary culture. The incredible success of the book and film of The Da Vinci Code revived curiosity about the history of gnostic culture. It was a tale of hidden religious secrets and a band of initiates who preserved truths repressed for ages. Admittedly, Dan Brown’s potboiler left no mark on intellectual life, but it offered a tantalising glimpse of the gnostic alternatives to traditional Christianity.

The intellectual part is most evident in debates over gender. The existence of two sexes is fundamental to Christian marriage, and even to its theology. As mentioned above, this is based on Christianity’s esteem for the human body, which was created in the image and likeness of its creator. There is tension but no conflict between the body and the spirit.

The gnostics, however, believe that the body is a mere accessory to the spirit. Why shouldn’t it be altered if the spirit (or mind) wants? Amazingly, the Gospel of Thomas, a gnostic collection of the words of Jesus, anticipated transgender ideology by some 1800 years.

Jesus said to them, “When you make the two into one, and when you make the inner like the outer and the outer like the inner, and the upper like the lower, and when you make male and female into a single one, so that the male will not be male nor the female be female, when you make eyes in place of an eye, a hand in place of a hand, a foot in place of a foot, an image in place of an image, then you will enter [the kingdom].”

Even the ancient gnostic elitism is evident in today’s debate over transgender options. All the medical evidence suggests that most children who want to change their gender desist by the time they reach their late teens. Yet the evidence is blithely ignored because the children’s spirits feel uncomfortable in their bodies. They (and their counsellors) have access to secret wisdom which seems like psychobabble to science and medicine.

What about Pelagianism? While Gnosticism was essentially a rival to Christianity, Pelagianism is a true heresy, a corruption of Christian doctrines on grace. It may, in fact, be the only major heresy to originate in Britain. Its namesake, Pelagius (c. 360–418 AD), was an itinerant British monk who preached novel doctrines which were combatted by St Jerome and St Augustine, amongst others. Showing that social media trolls had nothing on him, Jerome ridiculed the origins of Pelagius, describing him as “stuffed with Scottish porridge” and therefore suffering from a weak memory.

But the heresy was serious enough. It had always been believed that Christ died to save mankind from their sins. Weakened as we are by original sin, his grace was required for us to overcome our weaknesses and sins. Pelagius denied this. Perhaps under the influence of the pagan Stoic philosophers, he taught that man could be good without grace and could attain the loftiest virtue if his will was strong enough. And perhaps as a reaction to Gnostic pessimism, he took a much sunnier view of the material world.

So – if carried to its ultimate conclusions — his system stripped Christianity of its supernatural dimension. As Pope Francis warns his contemporaries, “Christianity thus becomes a sort of NGO stripped of the luminous mysticism so evident in the lives of [the great saints]”.

In a certain sense, Pelagius did a service to the Christian faith. His errors were evident but novel and in combatting them, the early Church clarified its views on grace. As a heresy, Pelagianism soon disappeared under the hammer blows of Augustine. But it lingered on as an optimistic belief in the natural perfectibility of man and a secularised religion – if, indeed, religion was needed at all.

As with Gnosticism, the concern of Pope Francis is pastoral rather than historical. He believes that a latter-day Pelagianism persists in attitudes within the Church:

some Christians insist on taking another path, that of justification by their own efforts, the worship of the human will and their own abilities. The result is a self-centred and elitist complacency, bereft of true love. This finds expression in a variety of apparently unconnected ways of thinking and acting: an obsession with the law, an absorption with social and political advantages, a punctilious concern for the Church’s liturgy, doctrine and prestige, a vanity about the ability to manage practical matters, and an excessive concern with programmes of self-help and personal fulfilment.

But Pelagian notions persist in public life, as well. The notion that children are by nature perfectly innocent and corrupted by society is a familiar theme in the literature of the Enlightenment. As Jean-Jacques Rousseau said about his novel Emile, “this book … is simply a treatise on the natural goodness of man, intended to show how vice and error are foreign to his constitution”.

Pelagianism also leads to an atomised individualism, as the document Placuit Deo points out: “A new form of Pelagianism is spreading in our days, one in which the individual, understood to be radically autonomous, presumes to save oneself, without recognizing that, at the deepest level of being, he or she derives from God and from others”.

The barometer of attitudes like this is advertising. And with slogans like “just do it … worn my way … made by you … have it your way … #Imperfect” it’s clear that the marketing industry, at any rate, doesn’t believe that we need others to attain salvation.

So what lessons can fans of the Pope – anyone, really – take from his analysis of Gnosticism and Pelagianism? Hundreds and hundreds of years of history amply demonstrate that they have failed to bring salvation, to bring happiness to the world. They don’t explain the world as it is and they lead to “a self-centred and elitist complacency, bereft of true love”.

What’s the alternative? The Beatitudes, says Pope Francis. Perhaps it is time to take closer look at the time-tested power of Christianity to transform lives for the better.

Michael Cook is editor of MercatorNet. This article has been republished from MercatorNet under a Creative Commons license.