All the same a change was gradually wrought upon the habits of men’s minds. Their whole picture of the world was changed. Just as they would no longer see the spiritual reflected in the sensible or the universal and the particular as reciprocally symbolical, so the idea of the relationship between the physical body of Christ and his Mystical Body came to be forgotten. It was like a slow atrophy of an unused sense. Faith, though remaining orthodox, was no longer nourished by intelligence.
– Henri de Lubac, SJ, Catholicism: Christ and the Common Destiny of Man
De Lubac’s Catholicism was an attempt to recover the notion of the unitive aspect of the Gospel, an idea that was central to the church for its first ten centuries but has been slowly forgotten. De Lubac’s book is essentially a brief Summa, covering all the core aspects of Christian doctrine, but from the perspective of Christian unity.
To sum up: the purpose of the Gospel is not only to unite men to God, but also to unite men to each other in the church. De Lubac shows just how revolutionary this was in the ancient world, and how the theme runs throughout the old liturgies and writings of the church fathers: the oppositions of Jew-Greek, Greek-barbarian, slave-free, etc. no longer applied in the church (though they might in the world in which the church found itself immersed). The concept of “body of Christ” applied to the church or to the Eucharist was not seen as a nice metaphor, but as a metaphysical reality.
The quote above caught my attention because it reflects something I have tried to express, usually poorly, that atheism is the default position of the modern mind because of how the modern mind is conditioned to interpret nature. Atheism, like any ideology, has nothing to do with new data or information, because the human mind only accepts information through the filters it already has. The modern filters make it difficult to interpret the natural world as being good and as being inherently ordered, and because of that it is impossible to conceive of God.
Something like the Protestant Reformation was inevitable once the modern mentality replaced the medieval one sometime in the 15th century. Before that, the notion of splitting the church would have been received with horror: the whole point of the church was to unite.
The Reformation was the end of one civilization and the beginning of another, a true apocalypse. In the aftermath of that conflagration, faith was now seen not as the source of unity but the source of division, and it is seen as such to this day.
The modern idea is that humans need to unite around something else, some body of cold hard fact, but the various experiments in achieving that unity never come to fruition, the cold hard facts we are all supposed to accept keep changing on us. Humanity finally accepting the same set of facts and goods and living in peace is the secular eschaton, a mythical future event that has been always on the horizon for the last 500 years, but which is never any closer now than it was then. All the modern world knows for sure is where unity is not to be found – in the church.