fails to be effective, which is impossible. So that probabilism, which has been widely held and publicly taught for some centuries as a theory of morals without being condemned by the Church, cannot be a false system. [1] A third argument may be drawn from the approbation of the works of St Alphonsus Liguori by the Holy See. The decree of May 18, 1803, on the revision and approbation of the works of St Alphonsus with a view to his beatification, gives a list of his works and expressly states that after careful examination nothing reprehensible was found in them. Among the works mentioned is a dissertation on the moderate use of a probable opinion when it conflicts with a more probable opinion on the other side, published in 1755. In this dissertation St Alphonsus clearly and ably defends and proves probabilism; he never withdrew or corrected this dissertation, though to save his Congregation and the doctrine he afterwards modified the statement of his views. He followed probabilism in his choice of opinions while writing his great work on moral theology which subsequently, though he admitted corrections in details, remained substantially the same.
5. It has been already pointed out that, although we may lawfully adopt and follow a probable opinion, there is no obligation of doing so, and it will frequently be more perfect to follow an opposite opinion. It is not intended to propose probabilism as the ideal of Christian conduct; we go to ascetical writers and elsewhere for that. [2] Probabilism is especially an instrument of moral theology, to be wisely and prudently used by the confessor in the confessional, as the doctor uses his medicines in the sick room.
6. Theologians warn us that only experts can judge of the intrinsic probability of an opinion. Others must be content to be able to discover extrinsic probable opinions. They can do this by consulting approved authors. If they find that an opinion is held as probable by five or six authors of repute, and it has not become obsolete by new legislation, by decrees of the Holy See, or by the progress of theological opinion, they may act upon it as solidly probable. The Sacred Penitentiary, July 5, 1831, declared that a professor of theology or a confessor might follow in practice the opinions of St Alphonsus. In thus adopting extrinsically probable opinions with regard to conduct, the priest or the layman only does what anyone
