[ultima ratio]

What is non-essential for the validity of the Mass is often essential to liturgically express the faith. The idea of propitiation is an essential doctrine of the faith. But its absence in a liturgy would not render the Mass invalid--though it would render it offensive.

[ninenot]

The broader aspect involves the definition of 'culture.' Culture necessarily derives from 'cult.' Thus, it can be quite plain to an observer exactly what is the object of cultic worship simply by noting the 'peripherals.'

No question that incense is a part of the Catholic culture, at Mass and at devotions. Also no question that priests, deacons, and altar BOYS have swung censers. (In convents, nuns have, I suppose.)

But to define all but the text of the Mass and the celebrants' intention as 'peripherals,' or 'matters of doubt' is not realistic in the least.