The whole of Christianity is contained in a sign of the cross; no theory of Redemption expresses half as much as a simple crucifix hung on a wall, erected as a wayside shrine or put on a tomb or altar. … This is why mere believers can transmit the whole of Tradition, even when they are quite ignorant of the terminology and subtleties of dogma.
-Yves Congar, O.P., from his book, The Meaning of Tradition
What is mere Catholicism? For many, the term itself invokes a familiarity