Smith helps us to understand the true nature of liturgy, and thus, a fortiori, liturgical music:
The weakness of your seminary training in the art of worship is that it was built on the assumption that public worship is the public worship of God. No one, least of all the author, would deny that this is a very nice assumption and perhaps the way things ought to be. In point of fact, this is not the way things are; and if you are so foolish as to operate in the parish on this assumption, not only will you never be a bishop, you will never get out of the sticks.
What your good Christian people want to worship is not God but themselves; although they do not know this and only a pastor who expects to depart shortly for other fields of endeavor will have the temerity to explain it to them. However, you need to know it, for this is the correct assumption on which all successful public worship is built.
Moving on to liturgical music:
And what is the basis or principle by which this division [knowing good hymns from bad] is accomplished? Remember what we are seeking in those songs with high nostalgia-evoking potential. The simplest method of ferreting out these hymns is to classify the contents of the book as to whether a hymn is “objective” or “subjective.” Then discard all hymns marked “objective” and use only those on the subjective list. And the rule for testing a hymn is this: If it emphasizes the attributes of God — His majesty, power, mercy, goodness, love, etc. — or recounts in some manner the story of Jesus, it is an objective hymn and thus, with possible rare exceptions, unsuitable for a public worship service. If on the other hand, the hymn is preoccupied with the feelings, reactions, desires, hopes and longings of the individual worshiper, it is subjective and guaranteed to have a religious kick in it
Surely this is applicable, mutatis mutandis, to some of our current discernments and discussions about how to properly music the Roman liturgy.