Erroneous doctrines

These poisonous doctrines have utterly corrupted both public and private life: rationalism, materialism, atheism, have begotten socialism, communism, nihilism-evil principles which it was not only fitting should have sprung from such parentage but were its necessary offspring. In truth, if the Catholic religion is willfully rejected, whose divine origin is made clear by such unmistakable signs, what reason is there why every form of religion should not be rejected, not upheld, by such criteria of truth? (Papal Writings, Exeunte Iam Anno, 25 December 1888).
(J) Problems under consideration