This was a reaction against reason and a search more natural wholeness. The attack against the enlightenment had been started by Rousseau but the first one to see the actual dissatisfaction with reason and the ultra rational world of European Civilization before WWI was Weber.
This is clearly the reason for the radical movements of the twentieth century. The baal teshuva that feels the emptiness of secular America, the Communists and the Nazis-just some people went to religion to fill the emptiness and others went to secular religions like Nazism or Environmentalism or Radical Feminism.
All the above was stated clearly by Weber and later by Allen Bloom
I would like to defend the idea that problem with the Enlightenment goes back to Renaissance Italy from where the whole movement began with the Humanists and can even be traced back to Antiquity. The thing that makes me say this is the fact that even Renaissance Italy with all its glory fell into nothingness after 1500. From there it migrated to Northern Europe and eventually to the USA. But the seeds of its destruction are still there. It can't exist for any extended period without the Bible--without holiness, without a connection with numinous reality.
But this Bible [or Old Testament approach] can't work either without ancient Rome and Athens. Freedom and equality are in no way Biblical values. It's the unique combination of Athens, Rome, and the Torah that created Western Civilization.--and is needed for its continuance.
However there is a problem with how many people approach the Bible. They look at it as if it is porous. They feel they can put in any interpretation that suits their fancy. For this reason for Jewish people the books of Musar [books of ethics from Jewish thinkers in the Middle Ages] are essential. It is not that these books are so insightful into human nature or into the Divine Realms [like Isaac Luria]. It is rather that they excel in the one thing the Middle Ages excelled in: logical rigorous thought. There is almost no way to get a self consistent logical approach to the Torah without basing yourself on some Medieval thinker. The reason is that that is what they were good at in those days. It is the same reason why no modern commentary on the Talmud comes anywhere in lights years of one word of a Tosphot on the Talmud.
For Christian people this all would imply the need for them to learn the books of Aquinas, and Anselm and Abelard.
The modern Jewish synthesis of the medieval books of Musar are contained in the writings of the giants of the Musar movement of Israel Salanter.
[But sadly that movement fell into the trap of frumkeit and' or the pseudo science of psychology.]
But the original Musar movement was definitely on the right track.
For a good example of what is wrong with that movement today a glance at the garbage written in Michtav Meeliyuah of the books of Avigdor Miller will suffice.
In conclusion: You need a balance between Athens and the Torah. and neither one alone suffices. This was clearly the opinion of Maimonides and of Aquinas. And I would not even have to mention if if not for the problem that today the divorce between Torah and Plato and Aristotle has been completed to the detriment of both. and this divorce was definitely against the world view of the Rambam, and the Baali Musar from the geonic school like the Chovot Levavaot. [Though I admit that this modern religious fanatic approach was in fact quite in accord with the Rashba, and others of the anti Rambam school. I can not answer this objection except to say that I think the fanatic religious approach is not for everyone. But it might very well be for some people. there was even for me a period in my life that i could not dream of tearing myself;f away from the holy words of the Torah and Talmud for even a minute.--except during the time between morning seder and afternoon seder which was the time periods that i got married in.]