Apologeticae sive Theologiae Fundamentalis, Tomus I: Demonstratio Christiana

Supernatural revelation is specified by reason of the object that is manifested, by reason of the mode in which it is manifested, and by reason of the end for which it is manifested.

1. By reason of the object that is manifested, revelation is either formal or material. That revelation is called formal whose formal object alone (the motive of assent) is supernatural; that is called material whose material object (the argument) as well is supernatural.

Formal revelation, therefore, contains truths that are natural in themselves and on that account accessible to human reason (e.g. the existence of God, the immortality of the soul). For whatever things are natural are also capable of being perceived by natural light. There are, to be sure, countless things in the bowels of the earth or in the firmament of heaven that escape rational cognition, e.g. the number of stars, the essence of electricity, of light, of matter, of animal and vegetative life. Yet these truths remain hidden only per accidens, not per se. They escape the grasp of reason because of external difficulties, not because of their substance or matter itself. If, therefore, they are divinely revealed, they become supernatural with respect to the formal object (or motive or principle) by which they are made known to us; yet they remain natural with respect to the material object (or argument or substance) of the truth itself.

Material revelation, on the other hand, contains truths that are not natural in themselves and on that account are inaccessible to human reason. The very matter (substance or argument) of these truths is such that it cannot be known without revelation.

But a truth to be known can be inaccessible to reason in two ways: either absolutely (simpliciter) or only relatively (relative seu secundum quid).

That truth exceeds reason secundum quid whose existence reason cannot prove before revelation, but whose essence it is able to grasp after revelation, e.g. the institution of the Church, the infallibility of the Roman Pontiff. That these truths exist, reason cannot prove with certainty before revelation, although it can affirm their possibility or even their probability. After revelation, however, reason can understand what these truths are, how they are, and why they are. Hence they are rightly called praeterrational truths, or mysteries secundum quid (broadly so called, of the second degree).

That truth exceeds reason simpliciter whose existence reason in no way can prove without revelation, and whose essence it cannot grasp even after revelation has been made. For this reason truths of this sort are called suprarational truths, or mysteries simpliciter (strictly so called, of the first degree), e.g.¹ the mystery of the Trinity. Reason left to itself can prove the existence of the Trinity neither as certain, nor as probable, nor even as possible. Through revelation, however, it learns with certainty that the Trinity is; it also partly understands, i.e. by analogous notions, what the Trinity is; finally it shadows forth at least somewhat, by fitting similitudes, how and why there is a Trinity of persons in God.

2. By reason of the mode in which it takes place, revelation is either mediate or immediate.

It is immediate when God Himself communicates the truth with no legate interposed; it is mediate when God manifests the truth through a legate. The revelation that Moses, the prophets, and the apostles received was immediate; the revelation that the Israelites received through Moses, and Christians through the apostles, is mediate.²

In immediate revelation God must so affect the cognitive faculties that man clearly perceives the truth that is communicated, and knows with certainty that it is communicated to him by God. Since, however, the cognitive faculty is threefold, immediate revelation is likewise distinguished into a threefold kind: sensitive, imaginative, and intellective.

It is sensitive when God speaks to the external senses by voices and other sensible signs. To this belong not only audible voices, but also theophanies (God appearing in the flame of the bush; Daniel seeing the writing on the wall), symbolic visions (Peter seeing unclean animals), and types (the paschal lamb; the bronze serpent; the sacrifice of Melchisedech). Imaginative revelation is present when God opens the truth through a power or influence upon the internal senses. This He can indeed do either by impressing imaginary forms not received through the senses (for instance, if likenesses of colors were impressed in the imagination of one born blind) or even by forms divinely ordered from those that have been received from the senses (Jeremiah 1, 13 seeing a boiling pot; Amos 8, 1 a basket of summer fruit). Intellective revelation consists in this, that God produces intelligible species in the mind itself, as in an internal vision, in prophetic illumination, very often in ecstasy, and likewise in those men who receive infused knowledge and wisdom.³

In mediate revelation God must make men certain that the immediate revelation from which the mediate one is derived is true and divine; in other words: the preacher of revelation must prove that he is sent by God and is a legate for communicating the truth to men. But this divine mission He can render certain by divine signs, especially by miracles and by fulfilled prophecies.⁴

3. By reason of the end for which it takes place, revelation is either private or public.

Private revelation is that which is given for the benefit of one man alone, or at least not of all men. The persons to whom private revelation has been made are bound to believe it with divine faith; the rest, however, neither ought nor can believe it with divine faith, since such a revelation does not pertain to them. Moreover, certainty of its divine origin is had only most rarely; indeed, even the Church in approving private revelations does not declare them truly to be divine, but only that they contain nothing contrary to faith and morals. It is not lawful, however, to despise them, since they are probably divine and certainly useful.

Public revelation is that which is given for the common benefit of all men, namely to found, to develop, and to complete the true religion for the whole human race. It is of this revelation alone that we shall treat.