322 Q. How do we fail to try to know what God has taught?

A. We fail to try to know what God has taught by neglecting to learn the Christian doctrine.

323 Q. Who are they who do not believe all that God has taught?

A. They who do not believe all that God has taught are the heretics and infidels.

There are many kinds of unbelievers: atheists, deists, infidels, heretics, apostates, and schismatics. An atheist is one who denies the existence of God, saying there is no God. A deist is one who says he believes God exists, but denies that God ever revealed any religion. These are also called freethinkers. An infidel properly means one who has never been baptized--one who is not of the number of the faithful; that is, those believing in Christ. Sometimes atheists are called infidels. Heretics are those who were baptized and who claim to be Christians, but do not believe all the truths that Our Lord has taught. They accept only a portion of the doctrine of Christ and reject the remainder, and hence they become rebellious children of the Church. They belong to the true Church by being baptized, but do not submit to its teaching and are therefore outcast children, disinherited till they return to the true faith. A schismatic is one who believes everything the Church teaches, but will not submit to the authority of its head -- the Holy Father. Such persons do not long remain only schismatics; for once they rise up against the authority of the Church, they soon reject some of its doctrines and thus become heretics; and indeed, since Vatican Council I, all schismatics are heretics.