Musicians deprived of aesthetic taste will uselessly struggle to find suitable harmonies to the Gregorian melodies. Traite d’harmonie of Rameau (published in 1722)

No true admirer of Gregorian chant can help looking with dismay at present trends toward providing organ accompaniments for the liturgical melodies. This practice, although ostensibly meant to promote the chant, is actually bound to destroy it. To what extent it has dulled the minds of “those that should hear” became clear to me during a conversation with a group of young seminarists, whom I met in a train several years ago. When I mentioned my interest in Gregorian chant, one of them said, his face radiant with delight, “Oh, Gregorian chant is so wonderful in our church; we have an organist who makes it sound like Debussy.” I know that it does not always sound like that. In another church it may sound more like Vaughan Williams, and elsewhere like parallel organum. Invariably it will sound like “something” other than what it really is and what it should be. Moreover, the very variety of possibilities inherent in this practice is bound to weaken the catholicity of one of the most precious possessions of the Catholic Church, I have no right to voice an opinion in matters pertaining to the Church, but I am saddened to see a venerable tradition, which has been restored to new life after centuries of neglect and indifference, subjected once more to destructive practices.
—Willi Apel (January 1958)