After Vatican I, Newman suggests that a condition, in the order of knowing, for the reception of a magisterial dogmatic definition — conciliar in this case, but applying equally to papal ex cathedra definitions — is the reception of that definition by the faithful:
If the definition is consistently received by the whole body of the faithful, as valid, or as the expression of a truth, then too it will claim our assent by the force of the great dictum, ‘Securus judicat orbis terrarum.’ This indeed is a broad principle by which all acts of the rulers of the Church are ratified. But for it, we might reasonably question some of the past Councils or their acts” (Letter to the Duke of Norfolk, 303).
Strikingly, this notion of reception is endorsed explicitly by the Council Fathers at Vatican II, in Lumen Gentium:
This infallibility with which the Divine Redeemer willed His Church to be endowed in defining doctrine of faith and morals, extends as far as the deposit of Revelation extends, which must be religiously guarded and faithfully expounded. And this is the infallibility which the Roman Pontiff, the head of the college of bishops, enjoys in virtue of his office, when, as the supreme shepherd and teacher of all the faithful, who confirms his brethren in their faith, by a definitive act he proclaims a doctrine of faith or morals…The infallibility promised to the Church resides also in the body of Bishops, when that body exercises the supreme magisterium with the successor of Peter. To these definitions the assent of the Church can never be wanting, on account of the activity of that same Holy Spirit, by which the whole flock of Christ is preserved and progresses in unity of faith. (Lumen Gentium, Sec. 25)