“Embedded in the Enlightenment’s (re-)definition and elevation of reason is the creation and subjection of an irrational counterpart: along with the emergence of reason as both the instrument and essence of human achievement, the irrational came to be defined primarily in opposition to what such thinkers saw as the truths of their own distinctive historical epoch. If they were the voices of modernity, freedom, liberation, happiness, reason, nobility, and even natural passion, the irrational was all that came before: tyranny, servility to dogma, self-abnegation, superstition, and false religion. Thus the irrational came to mean the domination of religion in the historical period that preceded it.”
~ Roxanne Euben
As strange as it sounds, the concept of religion as it has been handed down to us is itself a creation of the modern world. When civilizations were ordered on the basis of action informed by knowledge, which is to say, where the superiority of knowledge to action was acknowledged in the social structure itself, there was no question of “religion” as a separate entity, muscling its way in against other entities vying for power in the social sphere. The traditional world saw reality itself, at all levels, as a sacred experience. There was no level of activity that was not permeated by some higher significance. Everything was connected in a concentric circles, at the center of which sat transcendence, and this is why even crafts such as saddle-making had “theologies” and “initiations” for guild members only. These practices sprung from their perception of reality and not from the dictates of a religious power imposing them where they did not belong. For men of this mentality, there was no such thing as “spiritual life” vs. “ordinary life,” with the two cleanly separated into a dichotomy.
With the Enlightenment and the rise of Rationalism, that was all to change. Descartes rationalism is itself based on a mind-body dichotomy, or if not based on it, its practical effects were centered on this either/or. Once this doctrine of division was introduced into philosophy and then to the people, it is easy to understand that any practices, principles, or persons who are concerned with immaterial realities such as the soul would be relegated into the “mind” sphere and away from the realm of the body.
This was in line with the rationalist outlook but it was also very convenient for Enlightenment propaganda. The Enlightenment needed its own “founding mythology” in order to justify itself to itself and to future generations. Because the pride of the Enlightenment was its being “rational,” it clearly required an irrational “other” which it could claim to have conquered: this is religion. And so, the rationalists did not conquer religion so much as they re-structured the modern man’s view of the world in such a way that religion would be compartmentalized and rendered impotent. In this way, religion, as imagined in the modern world, is a child of rationalist propaganda.
 Roxanne L. Euben, Enemy in the Mirror: Islamic Fundamentalism and the Limits of Modern Rationalism (Princeton, NJ: Princeton University Press, 1999), 34.