Does the Bull Quo Primum enjoy infallibility?
It is a liturgical and disciplinary law of the most solemn kind. However, it does not have the infallibility of the Extraordinary or Solemn Magisterium of the Church, for it is not a dogmatic definition. Nevertheless, it is perfectly true to state that it participates in the infallibility of the Ordinary Magisterium, in an indirect manner. I say in an indirect manner, for underlying the whole decree are the unchanging truths of the Catholic Faith concerning the Mass as a propitiatory sacrifice, renewing in an unbloody manner the sublime act of worship accomplished on Calvary. Inasmuch as the purpose of the Bull is to protect these dogmas from the corruptions introduced by the heretics, denying such dogmas as the Real Presence, and inasmuch as these dogmas have always been taught in the Church, it shares in the infallibility of the Churchs doctrinal teaching. It is in this sense that universal liturgical and disciplinary laws in the Church are infallible (cf. Vacant, Le Magistre Ordinai
