Now, in the present time, dissent on various teachings of the Church is commonplace, even among Catholics. One can reject the authority of the Church outright, as dissenting Catholics do, or one can fashion a ‘Church’ in one’s own interpretive image, as Protestants do, and convince oneself that one is submitting to the Church. But both actions are rejections of the divinely established authority through which faith adheres to the articles of faith. For the reasons St. Thomas explains, where there is faith there can be no picking and choosing from among the Church’s teachings, because what makes faith to be faith is not essentially the set of articles believed, but the basis on which they are believed, namely, the authority of God, given to the Church to teach and interpret the deposit of faith.
Faith is not faith merely because of what is believed, he says, but because of the basis on which things are believed, which must be (as St. Thomas says) the authority of the Church.
Consequently whoever does not adhere, as to an infallible and Divine rule, to the teaching of the Church, which proceeds from the First Truth manifested in Holy Writ, has not the habit of faith, but holds that which is of faith otherwise than by faith.