What kinds of things are mutable in Latin Rite Catholic Liturgy? I got this email excerpt from the Compendium of the Catechism of the Catholic Church emailed to me today.


Is everything immutable in the liturgy?

In the liturgy, particularly in that of the sacraments, there are unchangeable elements because they are of divine institution. The Church is the faithful guardian of them. There are also, however, elements subject to change which the Church has the power and on occasion also the duty to adapt to the cultures of diverse peoples.

What are some examples of the &quot;elements which are subject to change&quot; and how have they done so over the years?  Has this change increased or remained steady since Vatican II?
Reform of the mutable aspects of the liturgy* has occurred throughout the Church's history. Pope St. Pius V standardized the Roman Rite in his 1570 bull Quo Primum, and Pope St. Pius X reformed the breviary in his Divino afflatu. John XXIII was the first in 1½ millennia to change the Roman Canon prayers of the Mass when he added St. Joseph's name to it.

For there to be a valid Mass, the form of consecration ("For this is my body…" and "For this is the chalice of my Blood…") cannot ever change. Defects that occur in the Mass (which may or may not render the Mass invalid) are summarized in Pope St. Pius V's De defectibus.

That the liturgy must "adapt to the cultures of diverse peoples" is a novelty since Vatican II. Liturgical reform prior to Vatican II has always been about better conforming the liturgy to God's liturgical law, transmitted via tradition through the Church. Just as the Old Testament Jews had ceremonial precepts* in which God prescribed exactly how they are to worship Him, so too does the New Law include liturgical law. 

*Ex. 32:17-19 (false worship of golden calf) shows how angry Moses got when the Jews violated liturgical law. They had good intentions (they thought the calf was a likeness of God and that they were honoring God by worshiping it), but they violated how God commanded they worship. They were so irreverent (shouting, singing, dancing) that Aaron thought there was a battle going on!

See:


Fr. Chad Ripperger's Topics in Tradition "Chapter 13: Modern Philosophy and the Liturgical Development"(cf. A Thomistic Perspective on Worship by Francisco J. Romero Carrasquillo of Ite ad Thomam blog, in which he shows that the virtue of religion, of which worship is the exterior expression, is grounded in the natural law)
Michael Davies's A Short History of the Roman Mass and Liturgical Time Bombs in Vatican II