See also the collected essays in Thornhill (1993) and the succinct summaries of scholarship on inbreeding by Blouin & Blouin (1988) and Harvey and Ralls (1986). I am grateful to biologists Susan Alberts and David Haig for directing my attention to these publications.
 Incisive criticisms presented by Judith Butler (1990) of Freudian and post-Freudian models of incest locate problems these binarisms pose for conceptualizations of sexuality and identity formation. See in particular chapter 2.
 While this is not the place to provide a sweeping survey of the vast literature on incest, I would like to note several of the most distinguished contributions, each of which participates in a larger mythology correlating incest avoidance with the emergence of culture: Durkheim (1963 [org.1898]); Kroeber (1939); Lévi-Strauss (1949); Mead (1963). See also the important study by Fox (1980), who re-examines the incest prohibition as a marker of the emergence of culture and society.
 The means of cultural transmission, its differing technologies and evolving modes of communication generate specific problems and may appear to offer up immediately and in their own rights, as if through their very novelties, new ontological fields within which culture could become radically redefined. But as Derrida's examination of Condillac's Essai sur l'origine des connaissances humaines demonstrates, "the representative structure which marks the first stage of expressive communication, the idea/sign relationship, will never be suppressed or transformed" (313) as a result of the evolution of technologies of representation alone.
 See Jakobson's study entitled "What is Poetry?" (368-378).
 Kristeva develops a correlation between poetic language and incest through a Lacanian reading of the role of language in subject-formation: "Language as symbolic function constitutes itself at the cost of repressing instinctual drive and continuous relation to the mother. On the contrary, the unsettled and questionable subject of poetic language (for whom the word is never uniquely sign) maintains itself at the cost of reactivating this repressed instinctual, maternal element. If it is true that the prohibition of incest constitutes, at the same time, language as communicative code and women as exchange objects in order for a society to be established, poetic language would be for its questionable subject-in-process the equivalent of incest: it is within the economy of signification itself that the questionable subject-in-process appropriates to itself this archaic, instinctual and maternal territory; thus it simultaneously prevents the word from becoming mere sign and the mother from becoming an object like any other -- forbidden" (136). What is unclear, here, is how we go about distinguishing Lacanian language as such (the space of the paternal and symbolic) from Kristeva's notion of (maternal) poetic language. I would prefer to emphasize that even 'language' (everyday language, referential language, and so on) only functions insofar as it employs figuration. It is perhaps more useful to understand these kinds of languages in terms of a spectrum of degrees of figuration (and incestuousness) rather than attempt to polarize language in terms of gendered paternity/maternity.
 Aquinas's exception is not made without a certain nervousness. For one, he refers to this special case of incest obliquely and abstractly: "The same unseemliness is not present when the parties are not related to one another directly, but through their parents. This varies according to customs and laws, whether human or divine, for, as we have noted, intercourse [usus venereorum] being directed to the common good is subject to law" (241). After allowing that the problem involves the relativity of law, Aquinas cites Augustine (De civitate Dei 15.16): "The union [commixtio] of brothers and sisters goes back to olden times, when necessity compelled it; all the same so much the more damnable did it later become when religion forbade it" (241), who transforms the necessity of Adam and Eve's children to commit incest into a measure of the necessity to avoid incest subsequently.
 This phenomenon participates in a broad-scale European and Christian cultural pattern: of assigning authority and priority to the East while at the same time representing the Orient as the stage on which to remake the old new again. "It is as if, having once settled on the Orient as a locale suitable for incarnating the infinite in a finite shape, Europe could not stop the practice; the Orient and Oriental, Arab, Islamic, Indian, Chinese, or whatever, become repetitious pseudo-incarnations of some great original (Christ, Europe, the West) they were supposed to have been imitating. Only the source of these rather narcissistic Western ideas about the Orient changed in time, not their character" (Said 1978:62). See also Said (1984).