Summa Theologica, by St. Thomas Aquinas, [1947], at sacred-texts.com
We next consider what belongs to the bodily state of the first man: first, as regards the preservation of the individual; secondly, as regards the preservation of the species.
Under the first head there are four points of inquiry:
(1) Whether man in the state of innocence was immortal?
(2) Whether he was impassible?
(3) Whether he stood in need of food?
(4) Whether he would have obtained immortality by the tree of life?
Objection 1: It would seem that in the state of innocence man was not immortal. For the term "mortal" belongs to the definition of man. But if you take away the definition, you take away the thing defined. Therefore as long as man was man he could not be immortal.
Objection 2: Further, corruptible and incorruptible are generically distinct, as the Philosopher says (Metaph. x, Did. ix, 10). But there can be no passing from one genus to another. Therefore if the first man was incorruptible, man could not be corruptible in the present state.
Objection 3: Further, if man were immortal in the state of innocence, this would have been due either to nature or to grace. Not to nature, for since nature does not change within the same species, he would also have been immortal now. Likewise neither would this be owing to grace; for the first man recovered grace by repentance, according to Wis. 10:2: "He brought him out of his sins." Hence he would have regained his immortality; which is clearly not the case. Therefore man was not immortal in the state of innocence.
Objection 4: Further, immortality is promised to man as a reward, according to Apoc. 21:4: "Death shall be no more." But man was not created in the state of reward, but that he might deserve the reward. Therefore man was not immortal in the state of innocence.
On the contrary, It is written (Rom. 5:12): "By sin death came into the world." Therefore man was immortal before sin.
I answer that, A thing may be incorruptible in three ways. First, on the part of matter---that is to say, either because it possesses no matter, like an angel; or because it possesses matter that is in potentiality to one form only, like the heavenly bodies. Such things as these are incorruptible by their very nature. Secondly, a thing is incorruptible in its form, inasmuch as being by nature corruptible, yet it has an inherent disposition which preserves it wholly from corruption; and this is called incorruptibility of glory; because as Augustine says (Ep. ad Dioscor.): "God made man's soul of such a powerful nature, that from its fulness of beatitude, there redounds to the body a fulness of health, with the vigor of incorruption." Thirdly, a thing may be incorruptible on the part of its efficient cause; in this sense man was incorruptible and immortal in the state of innocence. For, as Augustine says (QQ. Vet. et Nov. Test. qu. 19 [*Work of an anonymous author, among the supposititious works of St. Augustine]): "God made man immortal as long as he did not sin; so that he might achieve for himself life or death." For man's body was indissoluble not by reason of any intrinsic vigor of immortality, but by reason of a supernatural force given by God to the soul, whereby it was enabled to preserve the body from all corruption so long as it remained itself subject to God. This entirely agrees with reason; for since the rational soul surpasses the capacity of corporeal matter, as above explained (Q[76], A[1]), it was most properly endowed at the beginning with the power of preserving the body in a manner surpassing the capacity of corporeal matter.
Reply OBJ 1 and 2: These objections are founded on natural incorruptibility and immortality.
Reply to Objection 3: This power of preserving the body was not natural to the soul, but was the gift of grace. And though man recovered grace as regards remission of guilt and the merit of glory; yet he did not recover immortality, the loss of which was an effect of sin; for this was reserved for Christ to accomplish, by Whom the defect of nature was to be restored into something better, as we shall explain further on (TP, Q[14] , A[4], ad 1).
Reply to Objection 4: The promised reward of the immortality of glory differs from the immortality which was bestowed on man in the state of innocence.
Objection 1: It would seem that in the state of innocence man was passible. For "sensation is a kind of passion." But in the state of innocence man would have been sensitive. Therefore he would have been passible.
Objection 2: Further, sleep is a kind of passion. Now, man slept in the state of innocence, according to Gn. 2:21, "God cast a deep sleep upon Adam." Therefore he would have been passible.
Objection 3: Further, the same passage goes on to say that "He took a rib out of Adam." Therefore he was passible even to the degree of the cutting out of part of his body.
Objection 4: Further, man's body was soft. But a soft body is naturally passible as regards a hard body; therefore if a hard body had come in contact with the soft body of the first man, the latter would have suffered from the impact. Therefore the first man was passible.
On the contrary, Had man been passible, he would have been also corruptible, because, as the Philosopher says (Top. vi, 3): "Excessive suffering wastes the very substance."
I answer that, "Passion" may be taken in two senses. First, in its proper sense, and thus a thing is said to suffer when changed from its natural disposition. For passion is the effect of action; and in nature contraries are mutually active or passive, according as one thing changes another from its natural disposition. Secondly, "passion" can be taken in a general sense for any kind of change, even if belonging to the perfecting process of nature. Thus understanding and sensation are said to be passions. In this second sense, man was passible in the state of innocence, and was passive both in soul and body. In the first sense, man was impassible, both in soul and body, as he was likewise immortal; for he could curb his passion, as he could avoid death, so long as he refrained from sin.
Thus it is clear how to reply to the first two objections; since sensation and sleep do not remove from man his natural disposition, but are ordered to his natural welfare.
Reply to Objection 3: As already explained (Q[92], A[3], ad 2), the rib was in Adam as the principle of the human race, as the semen in man, who is a principle through generation. Hence as man does not suffer any natural deterioration by seminal issue; so neither did he through the separation of the rib.
Reply to Objection 4: Man's body in the state of innocence could be preserved from suffering injury from a hard body; partly by the use of his reason, whereby he could avoid what was harmful; and partly also by Divine Providence, so preserving him, that nothing of a harmful nature could come upon him unawares.
Objection 1: It would seem that in the state of innocence man did not require food. For food is necessary for man to restore what he has lost. But Adam's body suffered no loss, as being incorruptible. Therefore he had no need of food.
Objection 2: Further, food is needed for nourishment. But nourishment involves passibility. Since, then, man's body was impassible; it does not appear how food could be needful to him.
Objection 3: Further, we need food for the preservation of life. But Adam could preserve his life otherwise; for had he not sinned, he would not have died. Therefore he did not require food.
Objection 4: Further, the consumption of food involves voiding of the surplus, which seems unsuitable to the state of innocence. Therefore it seems that man did not take food in the primitive state.
On the contrary, It is written (Gn. 2:16): "Of every tree in paradise ye shall [Vulg. 'thou shalt'] eat."
I answer that, In the state of innocence man had an animal life requiring food; but after the resurrection he will have a spiritual life needing no food. In order to make this clear, we must observe that the rational soul is both soul and spirit. It is called a soul by reason of what it possesses in common with other souls---that is, as giving life to the body; whence it is written (Gn. 2:7): "Man was made into a living soul"; that is, a soul giving life to the body. But the soul is called a spirit according to what properly belongs to itself, and not to other souls, as possessing an intellectual immaterial power.
Thus in the primitive state, the rational soul communicated to the body what belonged to itself as a soul; and so the body was called "animal" [*From 'anima', a soul; Cf. 1 Cor. 15:44 seqq.], through having its life from the soul. Now the first principle of life in these inferior creatures as the Philosopher says (De Anima ii, 4) is the vegetative soul: the operations of which are the use of food, generation, and growth. Wherefore such operations befitted man in the state of innocence. But in the final state, after the resurrection, the soul will, to a certain extent, communicate to the body what properly belongs to itself as a spirit; immortality to everyone; impassibility, glory, and power to the good, whose bodies will be called "spiritual." So, after the resurrection, man will not require food; whereas he required it in the state of innocence.
Reply to Objection 1: As Augustine says (QQ. Vet. et Nov. Test. qu. 19 [*Works of an anonymous author, among the supposititious works of St. Augustine]): "How could man have an immortal body, which was sustained by food? Since an immortal being needs neither food nor drink." For we have explained (A[1]) that the immortality of the primitive state was based on a supernatural force in the soul, and not on any intrinsic disposition of the body: so that by the action of heat, the body might lose part of its humid qualities; and to prevent the entire consumption of the humor, man was obliged to take food.
Reply to Objection 2: A certain passion and alteration attends nutriment, on the part of the food changed into the substance of the thing nourished. So we cannot thence conclude that man's body was passible, but that the food taken was passible; although this kind of passion conduced to the perfection of the nature.
Reply to Objection 3: If man had not taken food he would have sinned; as he also sinned by taking the forbidden fruit. For he was told at the same time, to abstain from the tree of knowledge of good and evil, and to eat of every other tree of Paradise.
Reply to Objection 4: Some say that in the state of innocence man would not have taken more than necessary food, so that there would have been nothing superfluous; which, however, is unreasonable to suppose, as implying that there would have been no faecal matter. Wherefore there was need for voiding the surplus, yet so disposed by God as to be decorous and suitable to the state.
Objection 1: It would seem that the tree of life could not be the cause of immortality. For nothing can act beyond its own species; as an effect does not exceed its cause. But the tree of life was corruptible, otherwise it could not be taken as food; since food is changed into the substance of the thing nourished. Therefore the tree of life could not give incorruptibility or immortality.
Objection 2: Further, effects caused by the forces of plants and other natural agencies are natural. If therefore the tree of life caused immortality, this would have been natural immortality.
Objection 3: Further, this would seem to be reduced to the ancient fable, that the gods, by eating a certain food, became immortal; which the Philosopher ridicules (Metaph. iii, Did. ii, 4).
On the contrary, It is written (Gn. 3:22): "Lest perhaps he put forth his hand, and take of the tree of life, and eat, and live for ever." Further, Augustine says (QQ. Vet. et Nov. Test. qu. 19 [*Work of an anonymous author, among the supposititious works of St. Augustine]): "A taste of the tree of life warded off corruption of the body; and even after sin man would have remained immortal, had he been allowed to eat of the tree of life."
I answer that, The tree of life in a certain degree was the cause of immortality, but not absolutely. To understand this, we must observe that in the primitive state man possessed, for the preservation of life, two remedies, against two defects. One of these defects was the lost of humidity by the action of natural heat, which acts as the soul's instrument: as a remedy against such loss man was provided with food, taken from the other trees of paradise, as now we are provided with the food, which we take for the same purpose. The second defect, as the Philosopher says (De Gener. i, 5), arises from the fact that the humor which is caused from extraneous sources, being added to the humor already existing, lessens the specific active power: as water added to wine takes at first the taste of wine, then, as more water is added, the strength of the wine is diminished, till the wine becomes watery. In like manner, we may observe that at first the active force of the species is so strong that it is able to transform so much of the food as is required to replace the lost tissue, as well as what suffices for growth; later on, however, the assimilated food does not suffice for growth, but only replaces what is lost. Last of all, in old age, it does not suffice even for this purpose; whereupon the body declines, and finally dies from natural causes. Against this defect man was provided with a remedy in the tree of life; for its effect was to strengthen the force of the species against the weakness resulting from the admixture of extraneous nutriment. Wherefore Augustine says (De Civ. Dei xiv, 26): "Man had food to appease his hunger, drink to slake his thirst; and the tree of life to banish the breaking up of old age"; and (QQ. Vet. et Nov. Test. qu. 19 [*Work of an anonymous author, among the supposititious works of St. Augustine]) "The tree of life, like a drug, warded off all bodily corruption."
Yet it did not absolutely cause immortality; for neither was the soul's intrinsic power of preserving the body due to the tree of life, nor was it of such efficiency as to give the body a disposition to immortality, whereby it might become indissoluble; which is clear from the fact that every bodily power is finite; so the power of the tree of life could not go so far as to give the body the prerogative of living for an infinite time, but only for a definite time. For it is manifest that the greater a force is, the more durable is its effect; therefore, since the power of the tree of life was finite, man's life was to be preserved for a definite time by partaking of it once; and when that time had elapsed, man was to be either transferred to a spiritual life, or had need to eat once more of the tree of life.
From this the replies to the objections clearly appear. For the first proves that the tree of life did not absolutely cause immortality; while the others show that it caused incorruption by warding off corruption, according to the explanation above given.