Apologeticae sive Theologiae Fundamentalis, Tomus II (Pars Altera): Demonstratio Catholica

From the first part of fundamental theology it is established that the Christian religion is divinely revealed, because its author Jesus Christ is the Messiah sent by God, indeed God Himself.

Since, however, our Savior has again left the world, the question arises by what means He transmitted His revelation to posterity. Catholics answer that Jesus Christ transmits His revelation genuine and undefiled until the end of time through that religious organism which we call the Church of Christ. Jesus Christ, namely, founded an ecclesiastical society which would direct all the faithful, and in this society established an ecclesiastical teaching office which would teach all the faithful. Hence, according to Catholic doctrine, the Church is not something distinct from Christ and His religion; rather, she is the religion of Christ in the concrete, the Gospel "realized", the person of Christ always living and acting on earth in a mystical manner.

The non-Catholics, however, i. e. the adherents of those Christian communities which are separated from communion with the Roman Pontiff, hold one thing or another concerning the Church of Christ. Against them, entering upon the Catholic demonstration, we shall treat first of the Church as the society of the faithful and second of the Church as the teacher of the faithful.

The sources or seats of the arguments of the Catholic demonstration are all those historical documents from which the beginnings of the religion of Christ can be known: the books of sacred Scripture and the testimonies of Christian antiquity.

We shall use the books of sacred Scripture in the same sense in which we already used them in the Christian demonstration, i. e. we employ them not as inspired, but as merely historical.¹ Among these the Gospels stand out, inasmuch as they report the words and deeds of Christ preaching His religion and building up the Church. To these are added the other writings of the New Testament, in which the apostles and their disciples relate how the words and deeds of Christ pertaining to the Church are to be understood, and what the Lord prescribed to them to do for the preservation and progress of religion. But we shall also rightly bring forward the messianic prophecies of the Old Testament, which speak of the kingdom of God, since Christ Himself fulfilled them to the letter.

To the documents of sacred Scripture are added the testimonies of Christian antiquity, namely all the documents of the earlier age which regard the Church. Among these, the writings of the holy Fathers are of the greatest moment. These indeed we do not invoke as witnesses of divine Tradition (not yet proved), but as merely historical witnesses, eminent in antiquity, learning, and truthfulness. That the testimonies of the Fathers and of all Christian antiquity are not to be neglected, even the adversaries of the Church themselves concede, since they continually strive to strengthen their own opinions with these same testimonies.

The dogmatic definitions of the Church, as has already been said in the apologetic introduction, we do not bring forward for the sake of proof, but for the sake of completeness. Nevertheless, once the infallibility of the ecclesiastical teaching office has been demonstrated, we shall be able to use these same definitions as a most firm argument.