As regards matter, only doctrines of
faith and
morals, and facts so intimately connected with these as to require infallible determination, fall under the scope of infallible
ecclesiastical teaching. These doctrines or facts need not necessarily be revealed; it is enough if the revealed deposit cannot be adequately and effectively guarded and explained, unless they are infallibly determined.
But before being bound to give such an assent, the believer has a
right to be certain that the teaching in question is definitive (since only definitive teaching is infallible); and the means by which the definitive intention, whether of a council or of the
pope, may be recognized have been stated above. It need only be added here that not everything in a
conciliar or
papal pronouncement, in which some
doctrine is defined, is to be treated as definitive and infallible. For example, in the lengthy
Bull of
Pius IX defining the Immaculate Conception the strictly definitive and infallible portion is comprised in a sentence or two; and the same is
true in many cases in regard to
conciliar decisions. The merely argumentative and justificatory statements embodied in definitive judgments, however
true and authoritative they may be, are not covered by the guarantee of infallibility which attaches to the strictly definitive sentences — unless, indeed, their infallibility has been previously or subsequently established by an independent decision.