Years ago I read Arthur Koestler’s The Sleepwalkers: A History of Man’s Changing Vision of the Universe, and, stopping by a local used book store, happened upon a copy, and bought it. Now I am slowly rereading it nearly fifty years after I first read it. It’s still a fascinating account, whatever one makes of Koestler’s reliability as an historian.
However, to get to the point. When we get to the early years of Christian dominance in Europe, a period of history which Koestler calls the “Dark Interlude,” we come to what he calls “The Age of Double-Think” (pp. 102 ff.). What is interesting about it is the way that the Christian mind, at this point, was split in two. Throughout this period, although the heliocentric universe had already been widely considered by Greek scientists, and, in fact, it was generally known, even to medieval scholars, that the sun had some influence on the orbits of the planets, the general Christian vision of the universe was geocentric. And so, as Koestler points out, while astronomers like Ptolemy created a celestial geometry, based on the Platonic dogma that motion in the heavens goes in perfect circles, in order to preserve the appearances, the cosmology of the church tended to be a kind of naive Aristotelianism. As Koestler says:
The highly ingenious systems of Aristotle’s fifty-five spheres , or Ptolemy’s forty epicycles were forgotten, and the complex machinery was reduced to ten revolving spheres — a kind of poor man’s Aristotle which had nothing whatever in common with any of the observed motions in the sky. The Alexandrian astronomers had at least tried to save the phenomena; the medieval philosophers disregarded them. (103)
Yet the appearances could not be completely forgotten, so the mind of medieval philosophy — or, perhaps more accurately, theology — was divided. Two completely different pictures of the earth and the cosmos co-existed. Maps of the earth, for instance, could be completely different, used for entirely different purposes. In the one case, they were pious representations of the earth based on the interpretation of scripture by the early church fathers — where, to take but one example, the earth was not thought to be flat but to slant from north-west to south-east, because in Ecclesiastes 1.5 it is written that “the sun goes down, and hasteth to his place where he arose. A consequence of this was the belief that rivers flowing south-east, like the Tigris and the Euphrates, were thought to flow faster because moving downhill, whereas the Nile is slow because flowing uphill! But at the very same time, very detailed charts were available for the purposes of navigation. And, as Koestler says:
The shapes of the countries and seas on the two types of maps are as unrelated to each other as the medieval idea of the cosmos and the observed events in the sky. [103-4]
Here is the Ebstorf Mappa Mundi (1235). Notice Jerusalem in the centre, the head of Christ at the top and his feet at the bottom, and hands on either side. It is a very large map, nearly 4 metres square, and is apparently interested in the distribution of bishoprics, but has little or no relationship to the actual geography of the world.
Here is an example of a 14th century chart of the Mediterranean (note the complex, and fairly accurate detail: necessary if you’re a navigator):
The same thing applied, as Koestler points out, to society. The disorder and misery of medieval society was intense, and yet the medieval chronicler had an archetype in terms of which real disorder could be ordered by ideal types of chivalry and virtue. On the one hand, as Koestler points out, “[h]umble refusals to take precedence in passing through a door take up a quarter of an hour, yet bloody feuds are fought for that same right of precedence.” (105) A complex world of rigid etiquette and precedence co-existed with a disordered world of warring baronies and religious hysteria, of poverty, disease, famine and war, and yet of perfect chivalry and pure, untarnished love.
Enough, though, of this little vignette of competing visions of the cosmos, world, and social order. The point that I am coming to is this. Just as people are now insisting that there is no incompatibility between religion and science, the very same might be said about those who lived during the middle ages. Two entirely different visions performing entirely different functions. In the one case we see a frozen waterfall, representing the Trinity, before which someone bows in humble adoration and thanksgiving. The next moment the same person, thinking scientifically, would never for one moment think of the features of the natural world he is examining as being revelatory in the same way. Koestler himself reveals the same form of double think, when he describes the ambiguity of purity and eroticism in the depiction of women:
When the mind is split, both halves are debased: earthly love sinks to the animal level, the mystic union with God acquires erotic ambiguity. 
But why debased? Earthly love is, at least in part, animal eroticism, and mysticism, however much the believer may want to separate it from the earthly and the human, just is earthly and human, and so shares in the erotic ambiguity of so much that pertains to the human.
This is why Christopher Hitchens’ book god is not Great is so important, in my view. It may seem obvious once it is pointed out to you, but it needs to be pointed out sharply. People tend to miss the repeated emphasis that Hitchens places, throughout the book, on the sheer humanness of religion, that is, on how obviously and sometimes distressingly human religion really is, especially when it most wants to consider its beliefs and practices of divine origin. The Qu’ran, like the Bible, betrays its human origins on every page. There may be moments of sublimity, but most of the text of the world’s sacred books is of the earth, earthy, of the human, often base and profane, and in that sense, even unworthy of the human. Christians sometimes point to Jesus’ commandment to love one another as being somehow uniquely Christian. And, of course, love is important, but in many respects the emphasis on love in the New Testament is on love of the brethren, that is, love for and care of one’s fellow believers. Paul, for example — if, indeed, it was Paul who wrote the letter to the Galatians — did not have much love for those believers who insisted that to become Christian one needed also to become a Jew. And he wished for those who were being circumcised to meet this demand that the knife should slip and they should be castrated! The Qu’ran says that there should be no compulsion in religion, and yet practically every page of the Qu’ran is marred by the hideous warnings of the torments that await those who do not accept the message of the Prophet.
This double-think is characteristic of religion, because we are human, and we share all the limitations and compulsions that characterise being human. On the one hand our vision is limited. We can only see a small part of the world, and only from one point of view. And on the other, as religious, we endeavour to see the world from the point of view of a god. God’s commandments are purely human in origin and purpose, and yet they are presented with all the force and singleness of purpose that we imagine that a god would have in delivering them. So, we see the world from our own point of view, but then we see the world as if from the point of view of eternity, and our own small purposes become universal purposes, our own small gifts are magnified by the imagined power of the one who fills us with his spirit. We are ourselves messengers of a higher power, whose purpose is pure, and whose ends are eternal. The belief that we are such messengers may give to the natural urge to goodness an urgency and intensity that can bring about deeds of great generosity and humanity; but it can, and often does, lead to enormous cruelty and inhumanity as well.
The point is that the religious mind is, and must be, divided. Since all religion is human, and yet pretends to be divine, and therefore to convey knowledge or truth that is not accessible to humans without revelation (a concept which is itself untenable), and since most such revelations are imagined to have been given centuries ago when our knowledge of the world was limited, the religious vision of the world, of the nature of being human, and of human relationships, must be correspondingly limited. In order to maintain one’s religious world picture in the face of the steady advance of knowledge, both scientific and historical, one must either interpret it in purely symbolical ways, or compartmentalise the mind to take note of the world as we know it to be, and yet at the same time to preserve an aspectival way of looking at the world from the point of view of one’s religious story.
The attempt to shape one’s religious views in such a way that they are consistent with science and the scientific account of the natural world is simply doomed from the start. It is a bit like trying to show that the two maps above can be placed in a one to one correlation with each other. Our scientific understanding of the world is undergoing constant change and growth. Religion is, by its very nature, rooted in the past. Of course, in truth all religions have evolved, and yet religions themselves cannot acknowledge this evolution. The “faith once delivered to the saints” is still, in some sense, the faith that is held by believers now, and every movement towards reform in religion tends to be a conservative movement towards the past, for that is where the wellspring of revelation is located. Double-think is the permanent state of the religious believer, who must both live in the world as it is, and as we come to know it to be, but also in the world as it has been revealed to be by whatever god or gods lie at the source of the religious tradition to which one belongs. This is particularly difficult to do in an age when our knowledge of the world is in a state of constant change and transformation. One inevitably ends up in a permanent state of double-think, and religious leaders are especially prone to this, because they have to try to make ancient messages relevant to a world which is alien to the world in which the religions had their birth.