A weakening of faith was the problem in Europe and it still is. Nationalism is not a substitute for numinous holy value. The complete rejection of the Middle Ages was a terrible mistake. In the Middle Ages it was the basic starting axiom that faith and reason are not at odds in any way.And the books written then in philosophy show a rigor that have never been excelled.
Later books of philosophy seems to excel in circular reasoning and often plain false principles that sound good at first.