The Schola Cantorum (Singing School) or just Schola is the ancient name given  to the professional choir that would sing at the traditional Latin Mass. Today in TLM communities that tradition continues, but it is also a  title conferred generally in cathedrals and parish churches supporting cathedral-like music programs to signify the peak professional singing group supporting orthodox music practices and repertoire in the Novus Ordo.
 

EDIFY FIRST - ASK QUESTIONS LATER

 

The reason why the church supports professional singers and has done so for a millenia is simple. The treasury of sacred music that Vatican II exorts us to preserve can only be performed at a high enough standard by professional adult singers to enable the edification of the faithful on a regular basis. It is also the reason why Vatican II encourages the development of singing schools for children because their sound, when well trained,  also has the capacity to edify.

The capacity to edify is the reason behind why cathedrals and other large churches aspiring to fulfil the Church's vision for music are very different from the music experience in the average american parish.  However, cathedrals can still find themselves struggling to find the needed musicians and singers when they are in smaller population centers.

Music that edifies is experienced differently to music that is consumed. Consumption is linked to past experience. Edification is free of the restraints of the past and looks to the promise of the future. Any music style we use in church that finds any of its major traits in the music from the secular world will be consumed. It has little to no chance to edify as our first response to that music is to try and connect to it through its familair traits - to like it or not like it.  if we are to have any hope of achieving edification - we need to abandon our worldly music listening approach - like or not like need to be put aside.

Consumed music comforts, excites, or connects us to others  or to past experience and memory. It is emotional and personal. It is inward reaffirming. It is nostalgic. It confirms who we were and are. Nostalgia. Unlike music that edifies, music that is consumed doesn't shout "You've been changed". 

When sacred music edifies it lifts us beyond ourselves and our emotions - it moves our perception out of time and space to contemplate the divine. However, all the right components have to present for this to happen. When we perceive pefection in the sound we are hearing (professionaly performed) and where the sum of what we are hearing is greater than its parts (true art) and when the sound is intellectually associated for us with sacred things, and when we truly believe in sacred things - that is we are a member of the faithful -  then and only then - an auditory impression of who we could be is created that sets in motion a desire to move in that same direction. It  propels us forward into escatological time. True sacred art makes the believer a better human being yearning for God.  

The edification of the faithful is the second of only two reasons Vatican II gave for the purpose of music in the Liturgy. The first is to give glory to God. When Handel was congratulated by the Earl of Sandwich, on the occasion of Messiah's first performance in London for its high entertainment value for the audience, Handel was completely shocked. "M'Lord", he said, " I did not wish to entertain them, I wished to make them better." Handel understood edify.