The quote relates to a remark I often make: While I care for no religion, I wish for everyone around me to be deeply pious. If they are not, I fear what they might be capable of. I say this knowing that being religious does not prohibit one from cruelty, but believing that in today's world, it makes cruelty less likely. I would not have made the same statement in the twelfth century.
[they asked] how in the world, at the height of European civilization, at the moment in the twentieth century, when it looks like we have the most sophisticated kind of society, many democracies in Western Europe—with its concern for individualism and individual rights—...can turn into the most regressive barbarism that's ever been seen. What they mean is fascism in general, which was all over Europe…
So, the Frankfurt School is literally trying to say: how could it be that at the height of European civilization, at the height of what seems the most rational civilization in history…, could we see this most irrational barbarism develop? The anti-Semitism. The Holocaust. The camps. How could this happen here…? And they tried to find a deep answer.
They argued that since the time of Homer, all through Western civilization, the differentiation between the ego of the aristocracy from body, women, and slaves, had been the way of enlightenment. That is, progress, whatever good it brought, came at the price of the separation of the rational ego of those in power from the emotion from the body and from others.
What they have in mind is this: ... the notion of the self of the individual who seeks power (members of the aristocracy in the modern world, members of the capitalist bourgeois—whoever) must differentiate itself from the lower classes. Those in power must say: I am not like them.
Now, how do they do that? They have to repress in themselves...their own bodily impulses and those things they have in common with the lower classes...Between he or whoever is in power and those who are to be controlled, there has to be a differentiation of self-understanding. The ruler must think: I alone am in control of myself...
The more you base social order on reason alone, the more you discover that reason has nothing substantive to say morally...The more the modern scientific consciousness becomes sophisticated the more it believes in nothing. And when it believes in nothing, it is led to use other human beings as objects for any kind of pleasure.
Now the unhappy conclusion to this, and it is very unhappy, is...the conclusion is the enlightened self—the whole notion of the Enlightenment of the eighteenth century...the belief that we are entering a new age where, if we get rid of superstition and perhaps to some extent tradition and aristocracy...and if instead we are going to enter an era where scientific search for truth is going to join with enlightened leadership and individual liberty...—...that whole enlightenment notion (freedom and power coming together)...this enlightenment self turns into the fascist self, capable of any act of subjugation of others.
The implication—and they say this explicitly, actually—is that while social freedom and the modern notion of the free society (individualism, democracy) is dependent on enlightened thought, enlightened thought must inevitably destroy itself in a new kind of barbarism.
—Lawrence Cahoone. Modern Intellectual Thought. Lecture 24: Existentialism and the Frankfurt School. The Teaching Company. 2010.