The Oxford Companion to Philosophy gives us the official version of the enlightenment:
“Reason is man’s central capacity.”
“Beliefs are to be accepted only on the basis of reason, not on the authority of priests, sacred texts, or tradition.”
“All men (including, on the view of many, women) are equal in respect of their rationality, and should thus be granted equality before the law and individual liberty.”
“Man is by nature good. (Kant endorsed the Christian view of a “radical evil” in human nature, but held that it is possible to overcome it.)”
“Both an individual and humanity as a whole can progress to perfection.”
“Tolerance is to be extended to other creeds, and ways of life.”
“The Enlightenment devalues local “prejudices’ and customs, which owe their development to historical peculiarities rather than to the exercise of reason. What matters to the Enlightenment is not whether one is French or German, but that one is an individual man, united in brotherhood with all other men by the rationality one shares with them.”
The first two propositions superficially sound like a commitment to the scientific method but somehow they have left out evidence, experiment, and observation. After dismissing religion, the Enlightenment demands adherence to three blatantly false religious beliefs, which beliefs contradict reason, experiment and observation far more blatantly than young earth creationism does.
All men are not equal, nor women equal to men, nor groups and categories of men equal to each other.
Nor is man by nature good. In the cold and morally neutral terminology of the dark enlightenment, the natural outcome is defect-defect, and avoiding this outcome, getting to cooperate-cooperate, becomes more and more difficult as the number of people that you have to deal with increases. It takes social institutions, and to deal with these ever larger scales, these institutions have to be ever more finely honed and precisely made, and are ever more vulnerable to entropy and error.
The “progress to perfection.” line is that our nature is entirely the result of environment. Just raise the self esteem of women and blacks, and everything will be lovely. This has been tried, and the outcome is far from lovely, but they just keep trying harder. The grotesquely inflated self esteem of blacks leads to blacks committing acts of violence against whites, and the grotesquely inflated self esteem of women leads to disastrous choices. They divorce the father of their children expecting to marry a six foot six athletic billionaire, or they marry late, or they do not marry at all.
The extension of tolerance is notoriously selective, and necessarily selective, for if tolerance is mandatory, freedom of association, freedom of assembly, and freedom of speech is forbidden, which is not very tolerant at all. Tolerance is not extended to the “intolerant” meaning not extended to those who prefer to cooperate with people who are cooperative, and who prefer to refrain from cooperating with those who defect. Hence the financial crisis. Official minorities and single women, and in particular minority single women, and in particular blacks, and in particular black single women, generally do not repay mortgages. Any criterion that leads to banks extending loans to people that are inclined to repay, leads to banks discriminating against minorities, single women, and especially blacks. Which is forbidden. And so the 2007-2008 financial crisis. So the enlightened tolerate Muslims blowing people up and raping infidel women, but do not tolerate whites hanging out with people who are inclined to pay their debts. That is one creed and one way of life that they are not inclined to extend tolerance to. Forbidding an ever increasing range of speech and association is necessarily intolerant. We should stick to suppressing dangerous lies and heresies that aggressively pursue political power (such as The Enlightenment). Any suppression of freedom of speech, association, and assembly that goes beyond this is excessive and damaging. Official tolerance is inherently and necessarily dangerously intolerant.
Civilization is the advance of technical and scientific knowledge, and most importantly, social organization. Most of all it is the capability to maintain cooperate/cooperate relationships in very large groups. You will notice that the enlightenment is a root and branch attack on civilization, and Rousseau explicitly framed it as an attack on civilization and intent to destroy civilization.
The devaluation of local prejudices and customs is the dismantling of Chesterton’s fence, the abandonment of the slowly and painfully accumulated habits, customs, laws and institutions that make civilization possible, the devaluation and abandonment of the roots of Western Civilization. Our Cathedrals are empty and abandoned.