Better known as "full, active, and conscious participation", this excerpt from the Vatican II constitution on the liturgy, Sacrosanctum Concilium, is often quoted in order to bolster the idea that all the faithful should be singing at Mass.
However, Pope Benedict XVI has this to say from his Homily on the Regensburg Tradition and the Reform of the Liturgy (The Essential Pope Benedict XVI, Ed. Thornton & Varenne, Pub. HarperOne.):
Whenever an exaggerated concept of 'community' predominates, a concept that is...completely unrealistic precisely in a highly mobile society such as ours, there only the priest and the congregation can be acknowledged as legitimate executors or performers of liturgical song.
Today, practically everyone can see through the PRIMITIVE ACTIVISM and the INSIPID PEDAGOGIC RATIONALISM of such a position (emphasis mine), which is why it is now asserted so seldom. The fact that the schola and the choir can also contribute to the whole picture is scarcely denied anymore, even among those who erroneously interpret the council's phrase about 'active participation' as meaning external activism.
In other words, where the focus of the liturgy shifts from God to the people - the exaggerated concept of 'community' - there we find the wrong interpretation of "full, active, and conscious participation"; namely, that the congregation must sing and pray audibly at all times. What is the correct interpretation of participation qua the Mass? Benedict goes on, using the Sanctus as his example:
Through the choir, a greater transparency toward the praise of angels is rendered possible, and therefore a MORE PROFOUND INTERIOR PARTICIPATION in the singing than would be possible in many places through one's own crying and singing (emphasis mine).
Would we not do well, before moving on into the center of the mysterium, to be gifted with a period of well-filled silence in which the choir recollects us interiorly and leads each individual into silent prayer and, precisely in that way, into a union that can take place only on the interior level? Must we not relearn precisely this silent interior praying together and with the angels and saints, the living and the dead, with Christ himself, so that the words of the Canon do not become mere tired formulas, which we then try in vain to replace by constantly new and different word-montages in which we attempt to conceal the absence of any real inner experience of the liturgy, any movement beyond human talk into actual contact with the Eternal?