The first man did not see the Essence of God. For an intellectual being who saw God by Essence would be placed as man is with regard to Beatitude, which compels the will: for all fly from suffering and desire Beatitude; thus if the first man had seen the Essence of God he could not have sinned. His knowledge was, therefore, midway between that of the Blessed and that which is proper to our present state; for the higher a creature is, the more clearly it sees God. Hence God is seen in a more eminent manner through intelligible effects than through sensible ones; and since, in a state of innocence, the inferior faculties were subject to the superior, so that the superior part was not impeded by the inferior (as in our present state), the first man was not prevented by exterior things from a clear and constant contemplation of intelligible effects; but perceived the splendour of primordial truth by a knowledge natural or gratuitous.
Nor did the first man see the angels in their essence, for even before the Fall, when soul and body were perfectly adapted to each other, he understood by turning to phantasms. This inability to apprehend Spiritual substances did not proceed from the weight of the body, as after the Fall, but from the fact that the object which is con-natural to man's intelligence has not the perfection of immaterial substances. His knowledge of such was, however, superior to ours, for his apprehension of intelligible things had a clearness and certitude which are wanting to us. Hence Gregory says that man, in a state of innocence, conversed with the angels. Since God instituted all things in a perfect state, not only as they existed in themselves but also as they were to be the principle of others, man, who was to be a principle, not only by physical generation but also in regard of instruction and government, for which knowledge is required, had from the first an infused knowledge of all things in which mankind was intended to receive instruction. And since he required, for the government of his own life and that of others, not only natural knowledge but also supernatural, concerning the things of faith, he possessed of the latter whatever was requisite for his state; but things which exceeded his state or were unnecessary he did not know; such as the thoughts of men, future contingencies, etc.
Man, in his original condition, could not be deceived; for as truth is the good of the intellect, falsehood is its evil; hence as long as man preserved his innocence it was impossible that he should accept a false statement as true, although there might be ignorance of a particular truth. For as long as the soul is subject to God so long the inferior part of man is subject to the superior; and since the intellect is always true in regard of its proper object, in itself it is never deceived. Thus the integrity of man's original state was incompatible with intellectual deception, and if the seduction of the woman was not already preceded by the act of sin there must, as Saint Augustine says, have existed the internal sin of pride.
- text taken from Compendium of the Summa Theologica of Saint Thomas Aquinas, by Bishop Berardus Bongiovanni