What Sacrosanctum Concilium (and indeed, Vatican II as a whole) is most known for is the idea of "active participation" in the sacred liturgy. The introduction of this concept reads as follows in paragraph 14:
Mother Church earnestly desires that all the faithful should be led to that fully conscious, and active participation in liturgical celebrations which is demanded by the very nature of the liturgy. Such participation by the Christian people as "a chosen race, a royal priesthood, a holy nation, a redeemed people (1 Pet. 2:9; cf. 2:4-5), is their right and duty by reason of their baptism.
In the restoration and promotion of the sacred liturgy, this full and active participation by all the people is the aim to be considered before all else; for it is the primary and indispensable source from which the faithful are to derive the true Christian spirit; and therefore pastors of souls must zealously strive to achieve it, by means of the necessary instruction, in all their pastoral work.
This theory has led to armies of Extraordinary Ministers of Holy Communion, lectors, hospitality ministers, and the like, under the theory that as many people as possible must be able to "participate" in the Mass and that Mass is only meaningful if one has a task to perform.
There are two flaws with this theory. The first is a matter of semantics, but important nonetheless: the original Latin phrase is "actuosa participatio," which means actual participation. One can "actually" participate in the Holy Mass in any number of ways that do not require any physical or outward action.
The second flaw is more fundamental. Even assuming that the phrase is translated correctly in the English version of this constitution, why is the only way of "actively" participating to perform a task? Why can one not "actively" participate in the sacred liturgy through prayer, silent contemplation, following along in a Missal, or the like? I am a frequent attender of the Extraordinary Form of the Mass, and I feel like I participate more fully in the sacred liturgy through prayerful reading of the prayers of the Mass than I do attending Ordinary Form Masses, where I am concerned more with what responses to say or how loudly the person behind me is saying the responses.
(Side note: it really is not prayerful for me to be in a large congregation that is reciting something like the Our Father all at the same time. I feel like I am a part of the Borg collective.)
I think that this (incorrect) sense of what constitutes "active" participation has been severely detrimental to the spiritual life of the Church. No longer is the Holy Mass about the congregation assisting the priest by their prayers -- it is about making everyone feel welcome and involved in the liturgical happenings. Mass becomes dangerously close to merely a social gathering instead of the re-presentation of the Paschal Mystery.
I find it interesting that for all the focus on the "active participation" concept as it relates to laypersons, much of the Council Fathers' writing in this section has to do with the proper formation of clergy. According to the Fathers, priests are to be given significant training in liturgical matters as part of their formation. Those men who were already priests were to receive further education that delved into what exactly they were doing while celebrating the Mass and the meanings behind their actions. Finally, priests are to look after the liturgical instruction of the persons under their care, instructing them not only with words but also leading by example.
Tomorrow: Is the Novus Ordo Mass what the Council Fathers envisioned?