Human society was not born secular. Long before Christendom, the role of the shaman/priest in the political power structure was well established: druids in north-west Europe, court magicians in Egypt, emperor worship in Rome and so forth.
In that sense the secular state is a modern concept. This doesn’t necessarily mean it is wrong, simply that it must reflect a response to human history. I believe it’s fair to say that modern secularism really dates from the 18th century – in particular the thinkers of the French enlightenment. To understand why this was such a powerful intellectual trend, we need to go back a little further.
The 150 years following the reformation in Europe were marked by vicious wars of religion. The 30 Years’ War, fought by most major European powers in “Germany” (then of course a collection of principalities and statelets) killed or displaced 40% of the German population, with some horrific atrocities committed by all sides. By way of contrast, the second world war led to the deaths of only 10 per cent of Germany’s population.
In the UK, the war of the Three Kingdoms (a more accurate description for what used to be called the English Civil War), between Crown and Parliament led to the deaths of 30 per cent of the Irish population, 5 per cent of the English population, with regicide, an oppressive theocratic dictatorship, and a vicious counter-revolution, before ending in William of Orange’s coup d’etat against James II.
Now it’s easy to claim that religion was simply a pretext rather than real reason for these wars, but this is questionable. One of the leaders of the atrocities at Magdeburg justified his troops’ behaviour thus:
“I believe that over twenty thousand souls were lost. It is certain that no more terrible work and divine punishment has been seen since the Destruction of Jerusalem. All of our soldiers became rich. God with us”
Similarly, the arguments that the wars in Britain were about an emerging middle class rising against a long standing landed gentry rather than different theological positions has been pretty much discredited since Conrad Russell’s work on the subject . The English Civil War was about religion, just not quite in the way Sellars and Yeatman satirised.
This is the context in which the enlightenment developed. The horrors of the 17th century wars of religion haunted the enlightenment’s imagination in much the same way that the holocaust haunts ours. The assumption that if you let religion near power it doesn’t end well, most powerfully articulated by Voltaire in the Philosphical Dictionary, was not unreasonable in the circumstances.
“I was plunged in these ideas when one of those genii who fill the intermundane spaces came down to me. I recognized this same aerial creature who had appeared to me on another occasion to teach me how different God’s judgments were from our own, and how a good action is preferable to a controversy. He transported me into a desert all covered with piled up bones; and between these heaps of dead men there were walks of ever-green trees, and at the end of each walk a tall man of august mien, who regarded these sad remains with pity.
“Alas! my archangel,” said I, “where have you brought me?”
“To desolation,” he answered.
“And who are these fine patriarchs whom I see sad and motionless at the end of these green walks? they seem to be weeping over this countless crowd of dead.”
“You shall know, poor human creature,” answered the genius from the intermundane spaces; “but first of all you must weep.”
He began with the first pile. “These,” he said, “are the twenty-three thousand Jews who danced before a calf, with the twenty-four thousand who were killed while lying with Midianitish women. The number of those massacred for such errors and offences amounts to nearly three hundred thousand. “
In the other walks are the bones of the Christians slaughtered by each other for metaphysical disputes. They are divided into several heaps of four centuries each. One heap would have mounted right to the sky; they had to be divided.
“What!” I cried, “brothers have treated their brothers like this, and I have the misfortune to be of this brotherhood!”
“Here,” said the spirit, “are the twelve million Americans killed in their fatherland because they had not been baptized.”
“My God! why did you not leave these frightful bones to dry in the hemisphere where their bodies were born, and where they were consigned to so many different deaths? Why assemble here all these abominable monuments to barbarism and fanaticism?”
“To instruct you.”
In this context the desire to build a firewall between religion and government that flowed from Voltaire et al and was practically applied in, for example, James Madison’s contributions to the US constitution, is entirely understandable, yet it is an 18th century solution to a 17th century problem. Its limitations were exposed by French Revolution.
The enshrining of the Goddess Reason coincided with the Terror, which led 40,000 to the embrace of Madame Guillotine (including, ironically the founders of the cult of reason). Perhaps it’s the combination of any universal truth claim with untrammelled power that leads to disaster, rather than specifically religious ones. If such be so, perhaps we should think more deeply about how we limit power rather than which universal truth claims we refuse into the public square.