Book Four — Salvation, Chapter 83 — Summa Contra Gentiles
[1] From what has been set down it follows that aummg those who rise there will be no use of sexual activity or of food.
[2] For, when the corruptible life is taken away, those things must be taken away which serve the corruptible life. But clearly, the use of food serves the corruptible life, for we take
food to avoid the corruption which can follow on the consumption of natural moisture. At present, moreover, the use of food is necessary for growth; after the resurrection there will be no growth in men, since all will rise in their due quantity, as has been made clear. In the same way, the intimate union of man and woman serves the corruptible life, for it is ordered to that generation by which what cannot be perpetually preserved in the individual is preserved in the species. Now, it was shown that the life of those who rise will be incorruptible. Therefore, among those who rise there will be use neither for food nor for sexual activity.
[3] Again, the life of those who rise will not be less ordered than the present life, but better ordered. For man will reach that life only through God’s action, but he leads this life with nature co-operating. In this life the use of food is ordered to an end, for one takes food to convert it into the body by digestion. If, then, there is to be food at that time, it will be for the purpose of converting it into the body. Therefore, since nothing will be resolved from the body, because it will be an incorruptible body, we will have to say that everything converted into the body from nourishment must be devoted to its growth. However, man will rise in his due quantify, as was said above. Therefore, he will achieve a size beyond moderation, for an immoderate size is that which exceeds the quantity due.
[4] The man who rises, furthermore, will live forever. Therefore, either he will use food always, or not always but during a fixed time. But let him use food always: since the food will be converted into a body in which no dissolution takes place, it necessarily will cause an increase in some dimension and we will have to say that the body of the man who rises will be increased to infinity. And this cannot be, because increase is a natural motion and the intention of a natural moving power is never infinity, but is always something fixed. For, as the De anima [II, 4] says, “in everything established by nature there is a term of size and increase.” If the man who rises will not always use food, but will always live, one must grant a time in which he does not use food. Accordingly, this must be done from the beginning. Therefore, the man who rises will not use food.
[5] But if he will not use food, it follows that neither will he have sexual union for which the separation of the seed is required. Of course, the seed will not be separable from the body of the one who rises, nor from his substance. There is this reason: It is contrary to the seed in its essentials, for it would be seed as corrupted and as withdrawing from nature, and so it could not be the principle of a natural action, which the Philosopher makes clear in his De generatione animalium [I, 18]. And there is this reason as well: Out of the substance of those existing incorruptible bodies nothing will be able to be resolved. Finally, the seed cannot be the superfluity of nutriment if those who rise do not use food, as was shown. Therefore, among those who rise there will be no sexual union.
[6] Again, sexual union is ordered to generation. If, then, after the resurrection there is to be sexual union, it follows—unless it is to be in vain—that there will be human generation then just as there is now. Therefore, there will be many men after the resurrection who were not before the resurrection. In vain, then, does the resurrection effect this great difference: that all who have the same nature receive life at the same time.
[7] And again, if after the resurrection there is to be human generation, those who are generated will either be once again corrupted or they will be incorruptible and immortal. But, if they are to be incorruptible and immortal, the awkward consequences are many. First, indeed, one will have to hold that those men are born without original sin, since the necessity of dying is a punishment that follows on original sin. This is contrary to the Apostle’s word: “By one man came sin to all and by sin death” (Rom. 5:12). Next, it follows that not all would require the redemption which is from Christ, and so Christ will not be the bead of all men. And this is contrary to the Apostle’s teaching: “As in Adam all die so also in Christ all will live again” (1 Cor. 15:22). There would also be this awkward result: Men whose generation is the same would not have the same term of generation, for by generation from seed they achieve a corruptible life now, but then they would achieve an immortal one. Allow, on the other hand, that the men who will then be born will be corruptible and will die: if they do not rise again, it will follow that their souls will remain forever separated from their bodies. And this is awkward, since they are of the same species as the souls of the men who do rise. But if they, too, are to rise, their resurrection has to be waited for, by the others, that all who share the same nature may simultaneously receive that benefit of resurrection which is proper to the restoration of that nature (as is clear from what has been said). And, what is more, there does not seem to be a reason for waiting for the simultaneous resurrection of some, if one does not wait for the resurrection of all.