(LifeSiteNews) — There is a science that demonstrates – beyond all reasonable doubt – that the Catholic religion is true, and that assent to its truths is reasonable.

The first part of this series discussed the teaching of the Roman Pontiffs on the “motives of credibility,” those “wonderful and shining proofs” that “convince the human reason in the clearest way” that the Catholic Church has indeed received a revelation from God and practices the true religion.

The previous article explained that the truth of the Catholic religion can be recognized in a “common sense” way by those who encounter the Catholic Church for, as John Henry Newman wrote, “she bears upon her the tokens of divinity, which come home to any mind at once, which has not been possessed by prejudice, and educated in suspicion.” ^[1] However, Newman continued, “it is possible to analyze the arguments and draw up in form the great proof, on which her claims rest.” ^[2]

The science of Fundamental Theology draws up this “great proof,” and it is the purpose of this series to present it anew to modern readers with the following goals:

1. To strengthen the faith of those who already believe
2. To assist those do not yet believe to come to know Jesus Christ in His Church.

Before embarking on this journey, it will be helpful to study the road map that we will follow in a little more detail.

What distinguishes Fundamental Theology from other sciences?

In earlier articles, I have shown that the existence of God can be known by the light of natural human reason. The science that demonstrates this is Natural Theology. This science demonstrates that God exists and that He is infinite in all perfections. It brings us certain knowledge about divine attributes such as God’s eternity, immensity, ubiquity, immutability, omniscience, wisdom, freedom, omnipotence, and holiness. Natural Theology also demonstrates that God, the First Cause and Final End, sustains and governs all things by His Divine Providence.

A series on Fundamental Theology must take all the truths proven by Natural Theology for granted. Readers who would like to study the arguments by which these truths are established can find a simple and straightforward introduction in Theodicy, by Msgr. Paul Glenn, and a rigorous in-depth study in God: His Existence and His Nature by Reginald Garrigou-Lagrange, O.P.

The study of God as he is known in the supernatural light of divine revelation is called Sacred Theology. However, before we can study God in the light of this revelation, we must know that the claims of the Catholic Church to transmit an authentic revelation are credible.

Natural Theology cannot bring us this knowledge. As a branch of philosophy, it does not treat of those things that are historical in nature. i.e. that Jesus Christ lived, preached, was crucified, and rose from the dead.

Philosophy can tell us whether it is possible that God can reveal truths to mankind, but not whether He has done so on a particular occasion. Philosophy can tell us whether miracles are theoretically possible, but it cannot tell us about this miracle of turning water into wine, or that miracle of healing a man born blind. It cannot tell us whether Jeramiah spoke truly of the fate of Israel, or whether the prophecies of Isaiah have been realized in Christ.

Nor can the credibility of the Catholic faith be demonstrated by recourse to Sacred Theology. We cannot prove the possibility and credibility of Divine Revelation by recourse to truths that can only be known with certainty after that revelation has been accepted. Such a manner of proceeding would be a “vicious circle.” ^[3]

Therefore, we must show the credibility of the Catholic religion by using the natural light of reason to treat of questions that are both philosophical and historical.

This function is fulfilled by the science of Fundamental Theology.

Theologian Michaele Nicholau, S.J. explains:

Theology is the science of faith; fundamental Theology is the science of the foundations of the faith or the part of Theology that treats the foundations of the faith.” ^[4]

The “foundations of the faith” are those things that we must know before we can study those doctrines that have been divinely revealed, as divinely revealed. ^[5]

Apologetics as a subdivision of Fundamental Theology

We have seen above that Fundamental Theology treats of truths that must be established by the natural light of reason. However, there are truths that we know only by divine revelation, which are also traditionally dealt with in Fundamental Theology.

These are doctrines relating to (i) the infallibility and authority of the Catholic Church, as known by divine revelation (ii) the sources of revelation (Scripture and Tradition) and (iii) the act of faith itself.

These are necessary foundations for the study of the rest of Sacred Theology. We cannot proceed to study divine revelation without first understanding the authority by which the Church infallibly proposes it, the sources in which we are to find it, and the supernatural act by which the intellect assents to it as revealed.

Thus, Fundamental Theology is composed of two parts: (i) the part that examines the foundations of the faith in the light of natural reason and (ii) the part that examines the foundations of the faith in the light of divine revelation.

The part that examines the foundations of the faith in the light of natural reason is called Apologetics.

The subdivisions of Fundamental Theology

From what has been said above, we can understand why Fundamental Theology is traditionally broken down into four subdivisions, or “treatises.”

1. “The True Religion” or “Divine Revelation”

This first treatise of Fundamental Theology “undertakes to prove that there exists on earth one religion which has been revealed by God and meant for all men. That religion is the one brought to us by Jesus Christ, an authentic messenger from God; and that religion is, in the concrete, the religion professed by the Catholic Church.” ^[6]

This treatise is sometimes called “the True Religion” because it demonstrates that the Catholic religion is the true religion. Other authors call it “Divine Revelation” because, as Garrigou-Lagrange explains:

The subject of apologetics is God as revealed by himself, or God who reveals himself. Hence, apologetics is called “On Divine Revelation” or “On God Who Reveals.” ^[7]

This first treatise of Fundamental Theology is part of Apologetics because it proceeds by the natural light of reason.

2. “The Church of Christ”

In this second treatise of Fundamental Theology:

(I)t is demonstrated that Christ instituted a Church that truly merits the name “Church,” namely, a visible society, and that He entrusted to that Church His doctrine and bestowed upon her His own divine mission of saving souls.” ^[8]

And:

After studying the structure and characteristics of this Church founded by Christ, fundamental theology goes on to identify it with the Roman Catholic Church.

This study also forms of part of Apologetics, in that it demonstrates by the natural light of reason, the identity, authority, and infallibility of the Catholic Church, which must be known prior to the act of faith in the doctrine proposed by the Church.

Many authors then proceed to examine the same truths in the light of divine revelation, especially “the different hierarchical ranks within the Church, the Church’s infallible magisterium, and the Church viewed as Christ’s Mystical Body.” ^[9]

This second part of the treatise is theological, not apologetical.

3. “The Sources of Revelation”

The third treatise “deals with the two streams from which the Church draws her doctrine and her theologians their arguments, namely, inspired Scripture and sacred Tradition.” ^[10]

This treatise belongs to Fundamental Theology because it deals with the sources of revelation, knowledge of which is a prerequisite for the study of Sacred Theology.

This whole treatise is theological not apologetical.

4. “Divine Faith”

Finally, we have the fourth treatise, which “is concerned with the act whereby men believe, or the assent with which men embrace the truths revealed by God.” ^[11]

This is considered part of Fundamental Theology because Sacred Theology “essentially presupposes the faith.” ^[12] The study of the data of Divine Revelation from a perspective other than that of divine faith is not Sacred Theology.

This treatise also is theological rather than apologetical.

Conclusion

We now have our roadmap through the science of Fundamental Theology. In the next article, we will begin our study of the treatise on the “True Religion.”