From "AD PETRI CATHEDRAM" by Pope St. John XXIII
TRUTH AND ERROR9. It is clear that We are discussing a serious matter, with which our eternal salvation is very intimately connected. Some men, as the Apostle of the Gentiles warns us, are "ever learning yet never attaining knowledge of the truth." (5) They contend that the human mind can discover no truth that is certain or sure; they reject the truths revealed by God and necessary for our eternal salvation.
10. Such men have strayed pathetically far from the teaching of Christ and the views expressed by the Apostle when he said, "Let us all attain to the unity of the faith and of the deep knowledge of the son of God... that we may no longer be children, tossed to and fro and carried about by every wind of doctrine devised in the wickedness of men, in craftiness, according to the wiles of error. Rather are we to practice the truth in love, and grow up in all things in him who is the head, Christ. For from him the whole body (being closely joined and knit together through every joint of the system according to the functioning in due measure of each single part) derives its increase to the building up of itself in love."(6)
11. Anyone who consciously and wantonly attacks known truth, who arms himself with falsehood in his speech, his writings, or his conduct in order to attract and win over less learned men and to shape the inexperienced and impressionable minds of the young to his own way of thinking, takes advantage of the inexperience and innocence of others and engages in an altogether despicable business.