INCEST. — I. Concept.
Incest is the carnal sin between blood relatives or in-laws who, according to natural and ecclesiastical law, cannot validly contract marriage (v. AFFINITY; CONSANGUINITY).
St. Augustine rightly observes that, while at the beginning of the human race the union between brothers and sisters was a necessary condition for the propagation of the human race, once this necessity ceased, such a union was condemned by religion (De civit. Dei, XV.16.1: PL 41, 457-58). Consequently, at the beginning of the human race, the union between brothers and sisters should not be considered incestuous, since the Creator so disposed it for the propagation and preservation of the human race.
II. History.
1. Among primitive peoples
For a long time, considering the totemistic culture of Australia as the most ancient, it was held that the most ancient form of the prohibition of incest is that of the totemic clan, defined by Durkheim as «a group of individuals who consider themselves related to one another, but who recognize this relationship exclusively by this particular sign, namely that they are borne by the same totem» (v. TOTEMISM). In short, it was assumed that the most ancient humanity, not knowing marriage, lived under a prohibition of sexual relations and then, to remedy this, divided the clan first into two and later into more marriage classes with the law of exogamy. Hence the prohibition of incest is that of the totemic clan: «In brief, the two-class system has the effect of prohibiting marriage between brothers and sisters, but not always between parents and children, nor between the children of a man and those of his sister. The four-class system has the effect of prohibiting marriage between brothers and sisters and between parents and children, but not between the children of a man and those of his sister. Every subsequent dichotomy thus results in erasing a new class of relatives from the list of persons with whom marriage may be contracted, i.e., in adding one more to the list of prohibited degrees». This purely evolutionist theory has been superseded by modern ethnology through broader and more precise research, which shows that the most ancient form of marriage, as the great student of the psychology of peoples W. Wundt already recognized in 1912, is monogamy, and the social organization of Australian totemists with the prohibition of incest that accompanies it is not the most ancient.Among these ancestors, only the last, the closest one and his offspring are subject to the most rigorous prohibition of incest, and this is truly universal. Similarly universal is the prohibition of consanguineous kinship in relation to universal human brotherhood and that arising from different ancestors. Affinity is judged in a similar way to consanguinity.
How is the prohibition of incest explained? A distinction is made between the explanation of the particular forms of this prohibition, linked to different types of kinship, and that of the universal prohibition. The explanation of the particular forms is found in the formation of the type of civilization to which they belong; the universal prohibition, on the other hand, reduces to the question of why marriage and any sexual relations between parents and children and between brothers and sisters are prohibited.
Setting aside Durkheim’s explanation, according to which totemism gave rise to the belief that blood, especially menstrual blood, is the seat of magical virtues—a belief he considers the primary cause of exogamy, especially since the prohibition of incest appears to precede magical beliefs and since the evolutionist theory of primitive sexual promiscuity is unsustainable—there also fall McLennan’s explanation, based on the infanticide of female children, and Lord Avebury’s, based on the capture of women, etc.
Westermarck, Darwin, Havelock Ellis, and Crawley have advanced a psychological reason, according to which among persons, especially relatives, who live and grow up together from earliest childhood, those stimuli that lead to the passion of love and marriage do not develop at all or only with difficulty. This explanation, as Fr. Schmidt rightly observed, can at most justify the prohibition of incest between persons of the same age or generation, not that between parents and children, which is the gravest and most universally condemned. There may be some truth in it; the lack of sexual attraction that can lead to marriage is even more pronounced in the age difference between ascendants and descendants. But the most profound reason is in fact moral: the fact that parents must exercise their authority prevents them from contracting marriage with their children; the reverential fear that children have for their parents does not allow them to feel the desire to unite in marriage with their parents. The ethnologist knows well how much importance elders have in primitive societies, so that the young count for little or nothing and must learn and receive everything from the elders.
The ethical nature of exogamy among close relatives is then made perfectly clear by the prohibition of incest among close affines.
The reason given by primitive peoples for the prohibition of incest is a religious one. Thus the Semang of the Malay Peninsula, when an incest is committed, an adultery, say: *Lavaid Karé*, that is, sin against *Karé* (God). Similarly, among the Tungus, when it is necessary to form a new exogamous unit by dividing the clan, counting five generations, a sacrifice is made to *Buga*, the Supreme Being, the author of moral order, to announce to him the fact of the exogamous division.
The prohibition of incest must have existed from the very beginnings of humanity. Admitting the unity of origin of the human race from a first human couple, as most anthropologists, ethnologists, and linguists now hold, it must also necessarily be admitted that the first marriages were between brothers and sisters. This, however, not as understood by evolutionists who suppose a primitive sexual promiscuity, but as an exception to the rule, an exception required by necessity, because such marriages had soon to be prohibited. This is indicated by many reasons. The family, as Fr. Schmidt rightly observed, is in itself centripetal, tends inward, but society needs a centrifugal tendency to grow. Now, if at the beginning of humanity there had not been exogamy among close relatives, the source of the increase of the human race would have dried up physically in the long run, through the infertility of marriage. This is observed among peoples reduced to small numbers, such as, for example, the Ainu, among whom extreme nervous irritability develops and they are heading toward rapid extinction.
Even from a moral point of view, as has been said, the authority of parents would have been lacking. With this, the most powerful foundation of all true culture would have been destroyed; tradition, with the transmission of what previous generations have done, would have become impossible.
From a purely social point of view, the consequences of incest, as the same Fr. Schmidt observes, would have been fatal. It would never have been possible to have those great social groupings that are indispensable for the full development of all human faculties.
Ethnologically, from the uniform form of the prohibitive law of incest, which is said to be universal, its existence at the beginning of humanity is deduced. Indeed, if the prohibition of incest in this form had not existed from the very beginning of humanity, but had been devised after the separation from the common center, there would have been not one but many forms of the prohibition of incest, as is observed in different types of civilization.
2. Jews
In *Gen. 19:31-38*, incest is condemned in the story of Lot and his two daughters. Later, Mosaic legislation prohibited unions between a mother and son, a son and his father’s wife, a brother and sister (whether uterine or full), a grandfather and granddaughter, a grandson and his father’s or mother’s sister, on the grounds, as the law states, that they are of the same flesh (*Lev. 18:7-15*). Among affines, unions between a nephew and his uncle’s wife, and between a father-in-law and daughter-in-law were forbidden (*ibid.*, 18:14-15). The penalties established for incest were severe: thus, whoever had relations with a stepmother, daughter-in-law, or stepsister (full or uterine) was to suffer death along with the woman (*ibid.*, 20:11, 12, 14, 17). It is stated that a grandson who commits incest with his paternal or maternal aunt is to suffer the penalty for his crime together with the woman (the penalty is not specified). If one commits incest with his uncle’s (paternal or maternal) wife, both shall die childless (*ibid.*, 20:19-21). In Deuteronomy, curses are pronounced against incestuous persons, and the gravest forms of incest are recalled (*Deut. 27:20, 22-23*).Holy Scripture also recounts the incestuous relations of Amnon, son of David, with Tamar, Absalom’s sister (*II Sam. 13:11-22*), and of Absalom with David’s concubines (*ibid.*, 16:21-22), among others. St. John the Baptist was imprisoned for reproaching Herod Antipas, who had unlawfully taken as his wife the wife of his living brother Philip (*Mk. 6:17-18*).
3. Romans
In ancient Roman law, incest was considered not only as a union with a Vestal Virgin but also as any union between persons bound by a prohibition of marriage based on the complex of traditional and religious norms known as *fas*. Even in the *lex Iulia de adulteriis*, according to recent scholarship, the concept of cases of incest is traced back to the *veteres mores* (cf. *Dig.* 23.2.29.1). In the classical period, however, not all violations of marriage prohibitions constituted incest; some fell under the concept of *stuprum*. On this new understanding, incest included unions between ascendants and descendants, even if the relationship was only by adoption, unions between siblings, those with a paternal or maternal uncle or aunt, and unions between affines in the direct line, even after the dissolution of the marriage that had created the affinity. Alongside these clear cases, classical jurisprudence likely included others, such as, for example, the union of a stepmother with the children born to her husband from a subsequent marriage after divorce, or that of a son with his father’s concubine.Imperial legislation in the postclassical era established new marriage prohibitions that could be linked to the ancient ones established by *mores* and thus considered under the concept of incest. Thus, unions between affines in the collateral line up to the second degree were prohibited, as were those between cousins, and, under the influence of the new religion, those between Christians and Jews.
According to recent scholarship, little importance should be attached to the distinction between *incestum iure civili* (prohibited by laws) and *incestum iure gentium* (prohibited by custom), a distinction that is likely postclassical, originating from Caracalla’s constitution that extended citizenship to the entire Empire, including those eastern provinces where unions condemned by Roman custom were widespread.
III. DISCIPLINE IN CHRISTIANITY
4. Before the *Codex Iuris Canonici*
The Apostolic Council of Jerusalem prohibited fornication and thus all incestuous unions condemned in the Pentateuch (*Acts 15:19-21*). St. Paul excluded from the community in Corinth a man who had taken his stepmother as his wife (*I Cor. 5:1-8*). The councils of the 4th century imposed severe penalties on the incestuous. Thus, the Council of Elvira, at the beginning of the 4th century, in canon 61, decreed that if a man married a Christian sister of his wife, both were to be deprived of communion for five years, unless reconciliation was granted earlier in case of danger of death (*Mansi*, II, 15-16). The Council of Neocaesarea (314-25) in canon 12 excommunicated until death a woman who married two brothers in succession, and, in the event of the death of one party, the other was to continue penance (*ibid.*, 539). The Quinisext Council (692) in canon 54 annulled incestuous marriages, excommunicating the transgressors for seven years (*ibid.*, XI, 698). The Council of Worms (888) in canon 32 prohibited incestuous marriages but allowed marriage when there was doubt about the prohibited degree. The Fourth Lateran Council (1215) in canon 50 removed the prohibition for the 30th and 20th degrees of affinity and restricted consanguinity to the 4th degree due to the difficulty of observing the prohibition at higher degrees (*Mansi*, XI, 1035-38).5. Current canonical discipline
The *Codex Iuris Canonici* has restricted the notion of incest. Previously, affinity arose even from an illicit relationship; now, such affinity is excluded. However, whereas previously only a ratified but unconsummated marriage gave rise only to an impediment of public honesty but not of incest, today affinity arises from every validly contracted marriage, even if unconsummated, and thus in our case, there would be incest if two affines committed a carnal sin. There is no incest in a union between those joined by legal or spiritual kinship, however such an impediment may be regarded in individual places—whether as diriment or prohibiting—since the bond is merely legal or spiritual.6. Canonical Penalties
St Paul and the Councils punished incest with severe penalties such as perpetual or temporary excommunication, corporal punishment, prohibition from contracting a new marriage, and penance of several years, as may be inferred from the penitential books of the 8th and 9th centuries (H. Wasserschleben, *Die Bussordnung der abendländischen Kirche*, nebst einer rechtsgeschichtlichen Einleitung, Halle 1851, passim; M. Schmitz, *Die Bussbücher und die Bussdisziplin der Kirche*, I, Mainz 1883; II, Düsseldorf 1898, passim).The Decretals prescribed excommunication *latae sententiae* for anyone contracting marriages within prohibited degrees. Moreover, Clement V canonized civil penalties such as confiscation of goods, exile, and flogging. In 1869, Pius IX abolished excommunication. However, the prohibition against contracting a subsequent marriage, established by the councils for those guilty of incest, appears to have been abrogated by custom; certainly, it was no longer in force before the *Codex Iuris Canonici* (P. Gasparri, *Tractatus canonicus de Matrimonio*, Rome 1932, p. 436, n. 713).
The *Codex Iuris Canonici* in can. 2357 § 1 sanctions: “Lay persons lawfully convicted... of incest are ipso facto infamous, in addition to any other penalties which the Ordinary may deem fit to impose.” In can. 2358, minor clerics guilty of incest are not only declared infamous ipso facto but are also subject to punishment according to the gravity of their offence; indeed, if circumstances are particularly grave, they may be dismissed from the clerical state. Can. 2359 § 2 ordains that clerics in sacred orders who commit incest in the first degree of consanguinity or affinity must be suspended, declared infamous, and if they hold an office, benefice, or dignity, they must be deprived of them; in more serious cases, they must be deposed.
An incestuous union may become a legitimate marriage when the impediment (if of ecclesiastical law) is dispensed by the competent authority. It should be noted that in petitions for dispensation from matrimonial impediments, the fact of incest had previously to be declared; otherwise, the dispensation was null, until the Holy Congregation of the Inquisition abrogated this sanction of nullity and declared that it was not even necessary to disclose the incest. Today, however, incest constitutes one of the grounds for granting dispensation in cases of ecclesiastical impediment.