private judgment and revelation

The intellect of man is active and independent: he forms opinions about everything; he feels no deference for another's opinion, except in proportion as he thinks that that other is more likely than he to be right; and he never absolutely sacrifices his own opinion, except when he is sure that that other knows for certain. He is sure that God knows; therefore, if he is a Catholic, he sacrifices his opinion to the Word of God, speaking through His Church. But, from the nature of the case, there is nothing to hinder his having his own opinion, and expressing it, whenever, and so far as, the Church, the oracle of Revelation, does not speak. (Newman Differences Among Catholics No Prejudice to the Unity of the Church)