In 1828, in the first edition of his dictionary, Noah Webster defined incest as “the crime of cohabitation or sexual commerce between persons related within the degrees wherein marriage is prohibited by the law of a country.”¹ As definitions go, this one seems rather straightforward. Yet, as far as incest goes, it presents numerous questions. The one thing we think we know about incest is that its prohibition is universal and has been in existence since humans organized themselves into something resembling families. Of course, this one thing is an illusion, and Webster’s definition gets at some the problems with...

Beginning in the mid-eighteenth century and reaching its apex in the mid-nineteenth century, a discourse of the private family came to dominate visions of social and political life in the United States. Where previously the family had been conceived as the central institution of social and economic life, serving as a “little commonwealth” analogous to the state, by the mid-nineteenth century, at least in prescriptive literature and sentimental novels, the family was private, increasingly cut off from economic production and political life. It did, however, retain a political function: the production and dissemination of virtue, morality, and chastity that ensured...

In 1843 the Dutch Reformed minister Philip Milledoler asked, “Is it lawful for a man to marry his deceased wife’s sister?” Noting this was “a question which may appear at first sight to be of minor importance,” Milledoler argued that “the minor importance of this subject . . . is . . . not real; for if we view it in its bearing upon the happiness of individuals—upon the purity of the church and upon the best interests of the community at large, we shall see that it involves consequences of deep, if not of vital importance to mankind...

In 1851, in response to a query concerning incestuous marriage from the London-based Marriage Law Reform Association (MLRA), Charles Mason, an Iowa Supreme Court justice, wrote, “our laws make no prohibitions what ever as to inter-marriages between kindred, nor has the crime of incest a place on our statute books.”¹ This was likely more than the MLRA was looking for when they circulated a query to jurists, theologians, and other public figures in the United States, “where law and public opinion concur in making no distinction between a marriage [with a deceased wife’s sister] and any other not prohibited in...

As theologians and jurists multiplied novel justifications and explanations of the incest prohibition, one remained mostly submerged: incestuous reproduction and its hereditary consequences. To be sure, on occasion a jurist or theologian invoked its potential for degenerative hereditary consequences, but this was usually a minority voice. Indeed, even when it was invoked, it tended to bear little scrutiny and was often at odds with other explications. For example, in 1810 Benjamin Trumbull, pastor of North Haven Congregation in Connecticut, included a reference to reproduction at the end of his contribution to the “marriage question.” “One view of the divine lawgiver...

In the 1860 novelAdela, the Octoroon, H. L. Hosmer, an antislavery minister and supporter of colonization, painted a picture of the depravity of plantation life based in the incestuous actions of slaveholders. When George Tidbald, a southern patriarch and congressman, returned to his plantation from Washington, D.C., he found one of his slaves on her deathbed. Crissy, the slave, was also Tidbald’s daughter, his lover, and the mother of his child. Disavowing this vexed web of relations, Tidbald assumed that it was the recent birth of a child and the physical difficulties of nursing that were at the root...

By the middle of the nineteenth century, the link between incest and the liberal subject had been fully established. Indeed, to think about the modernity of the liberal subject was to think about his relation to the incest prohibition, and his penchant for incest. The incest prohibition had been remade across the nineteenth century in order to both produce and regulate that liberal individual and the bourgeois, sentimental family. What had been primarily a theological, biblical prohibition had found a new foundation in natural law. That natural law, which made the nuclear family the only universal family formation by making...