FORNICATION. - From the Latin fornix, which designated a vaulted chamber or corridor, generally resulting from a supporting construction for stairways (stadiums, theatres, amphitheatres), and which was adapted for public use and also for the gathering of prostitutes. Christianity coined from it the terms fornicari fornicatio, which became customary to designate any carnal intercourse outside lawful marriage. In this sense they occur frequently in the Vulgate as equivalents of the Hebrew term zēnūnîm, which properly means sexual impurity, especially adultery, and metaphorically idolatry, insofar as it violates the nuptial bond between Israel and God.
An example of the first sense is found in the Gospel of Matthew (5, 32; 19, 9), where the term fornicatio in the clause excepta fornicationis causa means adultery; an example of the second sense is found in the Gospel of John (8, 41). The word acquired a technical meaning, whereby among medieval scholastics the term fornicatio designates that particular species of lust consisting in sexual union between two persons free from matrimonial bonds or other ties that would confer upon their sin the character of sacrilege or incest. This meaning has remained in the technical vocabulary of Catholic moral theology.
The principal question raised concerning f. in moral theology regards its unlawfulness. Greco-Roman civilization, while condemning adultery and incest, was not concerned with simple f. as a moral fault, except where it involved shameful licentiousness. Christianity immediately regarded f. as unlawful; the Apostolic Council of Jerusalem expressly forbade it to Christians newly converted from paganism (Act. 15, 20); Paul declares that fornicators, together with adulterers, are excluded from the Kingdom of God (I Cor. 6, 9). Patristic thought remained unanimous along the lines of apostolic teaching. Medieval theological speculation sought to determine the intrinsic reason for, and degree of, the immorality of f.: with very rare exceptions (Durando, Caranuele, and a few others), theologians agree in holding f. to be intrinsically and gravely unlawful, basing themselves both on revealed data and on arguments deduced from an analysis of the objective content of f.
These reasons, repeatedly set forth by s. Tommaso in his works (Sum. Theol., 2ᵃ-2ᵃ, q. 154, s. 2; C. Gent., I. III, cap. 122; De Malo, q. 15, ss. 1-2), locate the intrinsic unlawfulness of f. in its being devoid of the legal stability required by the end of human marital intercourse, which includes not only procreation but also the upbringing of offspring. The Aquinate’s exact words are reported: « Already in the animal kingdom it may be observed that, wherever the rearing of offspring requires the cooperation of male and female, the two are united in a definite and stable manner, as, for example, is observed among birds... Now it is evident that for the upbringing of the human being not only is the mother’s work required, to nourish him, but still more the father’s work, to instruct and protect him, and furthermore to develop him both spiritually and materially. It is therefore contrary to nature that marital intercourse should take place independently of every bond; rather, it is necessary that it take place between definite persons who are stably bound to one another. Moreover, the natural need felt by the male in the human species to know with certainty which are his children is intimately connected with the duty incumbent upon him to educate them. Now such certainty would not be possible if marital intercourse were free from every bond. Nature itself, therefore, demands that marital intercourse take place between two definite and identifiable persons; that is, the marital act requires the state of marriage. And since the state of marriage, having procreation as its end, most deeply concerns the common good, it is subject to law. F., therefore, as extramarital intercourse outside the law, is intrinsically sinful. Nor does it avail to object that someone might be willing to undertake the upbringing of offspring conceived in fornication; for the natural necessity of binding marital intercourse to the legally established married state, arising from reasons of a universal character, precedes and embraces all particular cases» (Sum. Theol., loc. cit.). S. Tommaso, and with him unanimously all Catholic moralists, declare f. to be a grave sin from the objective point of view, while recognizing how widespread and easy is the contrary erroneous subjective assessment in environments ignorant of and hostile to Christianity. The intrinsic reason advanced is deduced from the grave harm caused, on the universal plane, though not always in every particular case, to offspring born of a fornicatory union. The ecclesiastical magisterium has expressly pronounced on the intrinsic unlawfulness of f. by condemning, through pope Innocenzo XI, the following proposition: Tam clarum videtur fornicationem secundum se nullam involvere malitiam et ablum esse malum quia interdicta, ut contrarium omnino rationi dissonum videatur (Denz-U, 1198). The encyclicals of Leone XIII (Arcanum) and Pio XI (Casti connubii) on Christian marriage authoritatively reaffirm the traditional doctrine set forth above concerning the unlawfulness of all extramarital sexual intercourse (v. AMORE LIBERO; CONGUBINATO; MATRIMONIO; PROSTITUZIONE).
BIBLI: P. Godet, Fornication, in DThC, VI, cols. 600-11; H. Leshtr, Fornicatio, in DB. II, cols. 2314-17; A. Verneersch, De rasitate et de vitis contraris, 2ᵃ ed., Roma 1921; V. BIBLICA. delle voci connesse. Gaetano Corti