Western Europe had a more or less unified worldview until the end of the fifteenth century. There were variations within this 'eucumene' and some of them were treated pretty brutally, while others were allowed to contribute to the society's inner dialectic.
When this universal way of dealing with reality started to disintegrate, whole societies were pulled apart and many hundreds of thousands died in the resulting wars of religion. Diversity it seemed, was not a good thing.
The Western world thus had to develop a number of treatments for the pathological and chronic civil disorder that significant, uncontrolled differences of religious opinion had brought forth. One of these was the coercive state, but of course this introduced tensions of its own.
At the end of the eighteenth century there were a couple of revolutions which pointed to two contrasting long-term solutions to the problem. The first — the American — was grounded in the notion that people could hold very different opinions about the meaning of life and not want to do horrible things to each other. The second — the French — explored the possibility of an alternative, secular, one-size-fits-all system. (Get with the programme or the representatives of the collective will indeed do horrible things to you.)
In the course of the twentieth century these two strands of western political thinking engaged in a near apocalyptic confrontation, and after the biggest body count in history, victory appeared to belong to the liberal, pluralistic approach to human diversity.
But look closer and the situation has proved to be more problematic. A significant minority within the tradition of the American revolution have been putting themselves about in a more dogmatic and altogether less tolerant fashion. It could also be said that the totalitarian approach had not so much been conclusively defeated on the battlefield or in the debating chamber, but had instead collapsed much like the earlier medieval consensus as a result of failing to respond to the totality of human aspiration.
The bloody conflict between the two western secularisms brought an end to the region's imperial ambitions and as a consequence, peoples with a very different historical experience of the same basic problem and its related coping mechanisms started to migrate into the heart of western Europe.
This did not initially set off a new outbreak of the old pathology until the world's economy started to globalise and geographical barriers between cultures were effectively compromised by what the optimists dubbed the information super-highway. 'Progress', that great utopian goal of the liberal society, now appears to be seriously threatened by the disordered timelines of contemporary reality.
Many people look at the 'threat' posed by political Islam today and instinctively refer back to the medieval 'clash of civilisations'. In this type of discourse 'medieval' equals primitive, but in fact the Islam that confronted the unified Christian doctrine of that period was in many ways far more rational and sophisticated. It was also a key part of the intellectual trajectory of the West in the years before the generalised splintering of perspectives.
The Islam which is today seemingly reopening the West's old wound is a strange combination of distant historical and geographical throwback with a religious reworking of the totalitarian project. In other words a two-pronged mutant antagonist for the rather naïve view that things will now sort themselves out to the advantage of pluralism without the need for further conflict - because the advantages of cohabiting with people who see the world in a fundamentally different way are 'obvious'.
Meanwhile, is it any wonder that the intrusive, coercive state threatens a comeback?