This makes clear the reply to the first objection.
Reply to Objection 2: That the soul of the first man fell short of the knowledge regarding separate substances, was not owing to the fact that the body was a load upon it; but to the fact that its connatural object fell short of the excellence of separate substances. We, in our present state, fall short on account of both these reasons.
Reply to Objection 3: The soul of the first man was not able to arrive at knowledge of separate substances by means of its self-knowledge, as we have shown above; for even each separate substance knows others in its own measure.
Whether the first man knew all things?
Objection 1: It would seem that the first man did not know all things. For if he had such knowledge it would be either by acquired species, or by connatural species, or by infused species. Not, however, by acquired species; for this kind of knowledge is acquired by experience, as stated in Metaph. i, 1; and the first man had not then gained experience of all things. Nor through connatural species, because he was of the same nature as we are; and our soul, as Aristotle says (De Anima iii, 4), is "like a clean tablet on which nothing is written." And if his knowledge came by infused species, it would have been of a different kind from ours, which we acquire from things themselves.
Objection 2: Further, individuals of the same species have the same way of arriving at perfection. Now other men have not, from the beginning, knowledge of all things, but they acquire it in the course of time according to their capacity. Therefore neither did Adam know all things when he was first created.
Objection 3: Further, the present state of life is given to man in order that his soul may advance in knowledge and merit; indeed, the soul seems to be united to the body for that purpose. Now man would have advanced in merit in that state of life; therefore also in knowledge. Therefore he was not endowed with knowledge of all things.
On the contrary, Man named the animals ( Gn. 2:20 ). But names should be adapted to the nature of things. Therefore Adam knew the animals' natures; and in like manner he was possessed of the knowledge of all other things.
I answer that, In the natural order, perfection comes before imperfection, as act precedes potentiality; for whatever is in potentiality is made actual only by something actual. And since God created things not only for their own existence, but also that they might be the principles of other things; so creatures were produced in their perfect state to be the principles as regards others. Now man can be the principle of another man, not only by generation of the body, but also by instruction and government. Hence, as the first man was produced in his perfect state, as regards his body, for the work of generation, so also was his soul established in a perfect state to instruct and govern others.
Now no one can instruct others unless he has knowledge, and so the first man was established by God in such a manner as to have knowledge of all those things for which man has a natural aptitude. And such are whatever are virtually contained in the first self-evident principles, that is, whatever truths man is naturally able to know. Moreover, in order to direct his own life and that of others, man needs to know not only those things which can be naturally known, but also things surpassing natural knowledge; because the life of man is directed to a supernatural end: just as it is necessary for us to know the truths of faith in order to direct our own lives. Wherefore the first man was endowed with such a knowledge of these supernatural truths as was necessary for the direction of human life in that state. But those things which cannot be known by merely human effort, and which are not necessary for the direction of human life, were not known by the first man; such as the thoughts of men, future contingent events, and some individual facts, as for instance the number of pebbles in a stream; and the like.
Reply to Objection 1: The first man had knowledge of all things by divinely infused species. Yet his knowledge was not different from ours; as the eyes which Christ gave to the man born blind were not different from those given by nature.
Reply to Objection 2: To Adam, as being the first man, was due to a degree of perfection which was not due to other men, as is clear from what is above explained.
Reply to Objection 3: Adam would have advanced in natural knowledge, not in the number of things known, but in the manner of knowing; because what he knew speculatively he would subsequently have known by experience. But as regards supernatural knowledge, he would also have advanced as regards the number of things known, by further revelation; as the angels advance by further enlightenment. Moreover there is no comparison between advance in knowledge and advance in merit; since one man cannot be a principle of merit to another, although he can be to another a principle of knowledge.
Whether man in his first state could be deceived?
Objection 1: It would seem that man in his primitive state could have been deceived. For the Apostle says ( 1 Tim. 2:14 ) that "the woman being seduced was in the transgression."
Objection 2: Further, the Master says (Sent. ii, D, xxi) that, "the woman was not frightened at the serpent speaking, because she thought that he had received the faculty of speech from God." But this was untrue. Therefore before sin the woman was deceived.
Objection 3: Further, it is natural that the farther off anything is from us, the smaller it seems to be. Now, the nature of the eyes is not changed by sin. Therefore this would have been the case in the state of innocence. Wherefore man would have been deceived in the size of what he saw, just as he is deceived now.
Objection 4: Further, Augustine says (Gen. ad lit. xii, 2) that, in sleep the soul adheres to the images of things as if they were the things themselves. But in the state of innocence man would have eaten and consequently have slept and dreamed. Therefore he would have been deceived, adhering to images as to realities.
Objection 5: Further, the first man would have been ignorant of other men's thoughts, and of future contingent events, as stated above (A[3]). So if anyone had told him what was false about these things, he would have been deceived.
On the contrary, Augustine says (De Lib. Arb. iii, 18): "To regard what is true as false, is not natural to man as created; but is a punishment of man condemned."
I answer that, in the opinion of some, deception may mean two things; namely, any slight surmise, in which one adheres to what is false, as though it were true, but without the assent of belief---or it may mean a firm belief. Thus before sin Adam could not be deceived in either of these ways as regards those things to which his knowledge extended; but as regards things to which his knowledge did not extend, he might have been deceived, if we take deception in the wide sense of the term for any surmise without assent of belief. This opinion was held with the idea that it is not derogatory to man to entertain a false opinion in such matters, and that provided he does not assent rashly, he is not to be blamed.
Such an opinion, however, is not fitting as regards the integrity of the primitive state of life; because, as Augustine says (De Civ. Dei xiv, 10), in that state of life "sin was avoided without struggle, and while it remained so, no evil could exist." Now it is clear that as truth is the good of the intellect, so falsehood is its evil, as the Philosopher says (Ethic. vi, 2). So that, as long as the state of innocence continued, it was impossible for the human intellect to assent to falsehood as if it were truth. For as some perfections, such as clarity, were lacking in the bodily members of the first man, though no evil could be therein; so there could be in his intellect the absence of some knowledge, but no false opinion.
This is clear also from the very rectitude of the primitive state, by virtue of which, while the soul remained subject to God, the lower faculties in man were subject to the higher, and were no impediment to their action. And from what has preceded (Q[85], A[6]), it is clear that as regards its proper object the intellect is ever true; and hence it is never deceived of itself; but whatever deception occurs must be ascribed to some lower faculty, such as the imagination or the like. Hence we see that when the natural power of judgment is free we are not deceived by such images, but only when it is not free, as is the case in sleep. Therefore it is clear that the rectitude of the primitive state was incompatible with deception of the intellect.
Reply to Objection 1: Though the woman was deceived before she sinned in deed, still it was not till she had already sinned by interior pride. For Augustine says (Gen. ad lit. xi, 30) that "the woman could not have believed the words of the serpent, had she not already acquiesced in the love of her own power, and in a presumption of self-conceit."
Reply to Objection 2: The woman thought that the serpent had received this faculty, not as acting in accordance with nature, but by virtue of some supernatural operation. We need not, however, follow the Master of the Sentences in this point.