Pius XII, 1939-

persuade themselves that what they do not wish to be true, are false or at least doubtful.

For this reason divine "revelation" must be considered morally necessary, in order that those truths, which in the realm of religion and morals are not of themselves beyond the scope of reason, yet in the present condition of the human race, may be readily grasped by all with strong certitude and with no admixture of error.¹

Yet on the other hand the human mind can sometimes experience difficulties in forming a certain judgment "of credibility" about the Catholic faith, although so many wonderful external signs have been disposed by God, through which, even by the natural light of reason alone, the divine origin of the Christian religion can be proven with certainty. For man, whether induced by prejudiced opinions or instigated by desires and evil will, can refuse and resist not only the evidence of external signs, which is pre-eminent, but also the supernal inspirations which God brings into our hearts.

Anyone who observes those who are outside the fold of Christ, can easily see the chief ways upon which many learned men have entered. There are those who contend that the so-called system of evolution, not yet irrefutably demonstrated within the scope of the natural sciences, and admitted imprudently and indiscreetly, extends to the origin of all things, and who boldly entertain the monistic and pantheistic theory that the whole world is subject to continuous evolution. Indeed, the supporters of communism gladly employ this theory, to bring out more efficaciously and defend their "dialectic materialism," casting out of mind every notion of God.

2306. Such fictions of evolution, by which whatever is absolute, firm, and immutable, is repudiated, have paved the way for a new erroneous philosophy which, in opposition to "idealism," "immanence," and "pragmatism," has obtained the name of "existentialism," since it is concerned only with the "existence" of individual things, and neglects the immutable essence of things.

There is also a kind of false "historicism," which attends only to events of human life, and razes the foundations of all truth and absolute law, not only insofar as it pertains to the philosophical matters, but to Christian teachings as well.

2307. In such a great confusion of opinions as this it gives Us some solace to note those who not rarely today desire to return from the principles of "realism," in which they had once been instructed, to the well-springs of truth revealed by God, and to acknowledge and profess the word of God as preserved in Holy Scripture. Yet at the same time We must grieve that by no means a few of these, the more firmly they cling to the word