The clear and certain recognition of a great truth is seldom the work of a day.  We often possess it in a confused and hidden way, before we can detect, to a nicety, its exact nature and limitations.  It takes time to declare itself with precision, and, like a plant in its rudimentary stages, it may sometimes be mistaken for what it is not—­though, once it has reached maturity, we can mistake it no longer.  As Cardinal Newman observes:  “An idea grows in the mind by remaining there; it becomes familiar and distinct, and is viewed in its relations; it leads to other aspects, and these again to others....  Such intellectual processes as are carried on silently and spontaneously in the mind of a party or school, of necessity come to light at a later date, and are recognised, and their issues are scientifically arranged.”  Consequently, though dogma is unchangeable as truth is unchangeable, this immutability does not exclude progress.  In the Church, such progress is nothing else than the development of the principles laid down in the beginning by Jesus Christ Himself.  Thus—­to take a simple illustration—­in three different councils, the Church has declared and proposed three different articles of Faith, viz., that in Jesus Christ there are (1) two natures, (2) two wills, and (3) one only Person.  These may seem to some, who cannot look beneath the surface, to be three entirely new doctrines; to be, in fact, “additions to the creed”.  In sober truth, they are but expansions of the original doctrine which, in its primitive and revealed form, has been known and taught at all times, that is to say, the doctrine that Christ is, at once, true God and true Man.  That one statement really contains the other three; the other three merely give us a fuller and a completer grasp of the original one, but tell us nothing absolutely new.

In a similar manner, and by a similar process, we arrive at a clearer and more explicit knowledge of other important truths, which were not at first universally recognised as being contained in the original deposit.  The dogma of Papal infallibility is an instance in point.  For though no Catholic ever doubted the genuine infallibility of the Church, yet in the early centuries, there existed some difference of opinion, as to where precisely the infallible authority resided.  Most Catholics, even then, believed it to be a gift conferred by Christ upon Peter himself [who alone is the rock], and upon each Pope who succeeded him in his office, personally and individually, but some were of opinion that, not the Pope by himself, but only “the Pope-in-Council,” that is to say, the Pope supported by a majority of Bishops, was to be considered infallible.  So that, while all admitted the Pope with a majority of the Bishops, taken together, to be divinely safeguarded from teaching error, yet the prevailing and dominant opinion, from the very first, went much further, and ascribed this protection to the Sovereign