Thesis VI

Fornication, whether wandering, or of one with one, and this whether transitory or constant, is prohibited by the law of nature; and even if to this there is added an agreement for nourishing and educating offspring, the condition of the thing is not substantially changed.

I. In marriage copulation takes place between those mutually obligated. We have already proved that this is good. In fornication, on the contrary, copulation takes place between those of whom the one does not have power over the other, and who therefore are not obligated, but unbound. It is asked what the law of nature establishes concerning this.

In the thesis we distinguish three things. For fornication is, first, wandering, that is, access now to this woman, now to that one, or to this man and that one, as happens in prostitution; second, it is of one man to one woman and conversely, and that in two ways: for such conjunction either is transitory, or it is constant, and this is called by the special name concubinage (whether the concubine is kept at home or outside, it is all the same to theologians). Moreover, to concubinage, and indeed to simple fornication, there can be superadded an agreement for nourishing and educating offspring, if offspring should supervene; but intercourse can also take place and be repeated without such an agreement.

We say, first: that any fornication whatever is illicit by positive divine law is manifest, since it is both prohibited by divine law and is numbered by the Apostle among those sins which exclude from the Kingdom of God. But it has been called into doubt by some whether, by the law of nature at least, it is always illicit. There exists the proposition condemned by Innocent XI, March 2, 1679: "It seems so clear that fornication according to itself involves no malice and is evil only because it is forbidden, that the contrary seems altogether discordant with reason."

II. Therefore we say, secondly, that fornication of any kind whatever (we now set aside the superadded agreement for nourishing and educating offspring) is opposed to the law of nature. The first argument can be sought from the common sense, not indeed of all men, but of men rightly using reason and having a more or less sound moral sense, such as Christians are. Now men of this sort abhor fornication not for this cause alone, that they know it has been prohibited by God, but because they regard it according to itself as indecent, dishonorable, pernicious, and contrary to the law of nature. A judgment of this sort, therefore, is indeed the judgment of reason healed by faith; but it is not a judgment which rests upon faith, which manifests the positive law of God, but rests upon the light of reason, which shows what is repugnant to nature. For a positive prohibition alone cannot be the reason why we flee from something as dishonorable in itself and repugnant to nature; for even something indifferent in itself can be prohibited. But the consensus of all who rightly use reason in those matters which are necessary for human and social life is a testimony of truth. Therefore.

Second argument. That is opposed to the law of nature which is repugnant to human nature itself. But human nature, at once sensitive and rational, requires this: that reason rule, and sense be subject to reason; and therefore those things are repugnant to the law of nature and are prohibited by it in which, the ordination of reason having been disregarded, sense alone dominates. But the ordination of reason is disregarded, indeed one goes against that very ordination of reason and sense alone dominates, when of some action or manner of acting there is no end of itself fitting to reason; indeed, when the end intended by nature of itself is excluded, and the end remains pleasure alone.

This, however, must be observed: that in order that a judgment be made concerning the natural honesty or dishonesty of some action, that must be considered which the action itself is of itself, or which belongs to it by reason of itself, not what is or can be accidentally, namely by reason of contingent circumstances or of the intention of the freely acting agent, unless through these it happens that the essence of the thing is changed, or that another moral essence succeeds. For the law of nature commands that which is good by its essence and prohibits that which is evil by its essence; therefore it looks at things or actions according to that which they are of themselves.

III. Let us now speak specifically of wandering fornication, that is, taken in its breadth so that it is the access of an unbound male to any unbound female whatever, and conversely of a female to any male whatever. Here a manifest disorder appears. For this conjunction has no end fitting to reason; indeed it is opposed to the end intended of itself by nature in the concubitus of man and woman. For the end of concubitus intended by nature itself (for those contracting can intend another end) is the procreation of offspring, but of offspring to be educated, so that man may exist in that mode which his own nature requires. But α) insofar as it is a woman who prostitutes herself to several men, procreation itself is impeded; β) insofar as it is a man who mingles with several women, or again a woman with men, the procreation of offspring intended by rational nature is not had; for offspring, which is a human being, must not only be begotten but nourished and educated by the parents. But fornicatory concubitus of itself lacks the due order to an end of this sort. For when two persons copulate fornicarily, their conjunction a) is transitory; from which it follows of itself that, from the very account of the act or union, provision is not made for the education of future offspring, and therefore this conjunction lacks the due order which it ought to have toward the end intended by nature; b) insofar as a man mingles with several women and the same women mingle with several men, certain offspring is not had, or this promiscuous use of itself brings in uncertainty of offspring; but that is wholly opposed to its due education. Besides, this fornicatory conjunction does not have as an end fitting to reason the mutual service and assistance of man and woman, or the family; indeed it excludes that very thing by the fact that it is a transitory copulation short of mutual obligation. It does not have as its end the repression of concupiscence; indeed it is altogether opposed to this end, because it indulges concupiscence at will. Nor d) can any other rational end, fitting of itself to this union, be devised. But the only end is the satisfaction of lust or of sensual pleasure; and wandering concubitus, insofar as it is such, of itself looks to this, that lust be satisfied. Therefore the intercourse of an unbound man with any unbound woman whatever, and conversely, is repugnant of itself to rational nature.

IV. But, secondly, is only this wandering concubitus with several persons repugnant to the law of nature, or also the concubitus of one with one, such as is also found in concubinage? Certainly it is; for if that which is of itself, not accidentally, is considered, in fornication even with one woman, the same disorder according to species appears in it as in manifold fornicatory intercourse. For it too is not ordered to the due education of offspring, but, this being excluded, to pleasure alone. For in the intercourse of man and woman, which by nature is ordered to the procreation and education of offspring, the conjunction of each must be such that of itself, or from the nature of the thing, there is certain mutual provision and care for offspring, and for that reason they obligate themselves mutually to common life. But in fornicatory intercourse there is of itself no such certainty of provision; rather of itself provision is altogether uncertain, because the mutual obligation of the man and the woman is excluded, which is the natural foundation of that certainty.

V. But what if to fornication or concubinage there is added an agreement for nourishing and educating offspring? Would satisfaction not thus be made to the exigency of nature? I do not think so. For, first, the first and second arguments which we gave under n. II would still have force; then, through an agreement of this sort, the condition of the thing, as regards the primary end of the work from the institution of nature (Thesis II, VI), is not substantially changed. Namely, the obligation of nourishing and educating offspring ought to inhere in the very conjunction of man and woman; for this is the end assigned by nature to the work toward which it tends. But that agreement is extrinsic to fornication or concubinage, and, no otherwise than other agreements entered into by choice, can be dissolved. Concubinage itself also can, indeed ought, to be dissolved at the will of those coming together; but once it has been dissolved, the observance of that superadded agreement will by that very fact totter. Therefore there is nothing which, in this hypothesis, makes the sustenance and education of offspring certain and secure. Certainly even fornicators and concubinarians are bound by the law of nature to nourish and educate offspring; but because nature demands this from all, therefore those coming together are bound to place themselves in that state which is suited to attaining this end. A state, I say; for there is question of a stable obligation. But such a state is not concubinage, which of itself is changeable and dissoluble at will; nor does the added agreement sufficiently contribute, since it does not change the essence of the conjunction, can be dissolved at the will of both, and, when concubinage ceases, is very probably in danger of ceasing. Therefore, before the intercourse of man and woman, there must precede the power of the one over the other and a mutual permanent obligation; in this thing the matrimonial union is situated.

And indeed the very law of nature dictates that common offspring is to be nourished and educated in common by its progenitors. Either, therefore, each seriously obligates himself or herself to this from the beginning, and by this very fact will obligate himself or herself to a stable mutual union, and there will be had, what nature requires, a matrimonial union; or each does not obligate himself or herself to this, and thus the observance of the law of nature will not be placed in safety.