Two Heads Two Souls? Conjoined Twins in Theological Quodlibeta (1270-c.1310)

Abstract: This article focuses on the case of conjoined twins in a selection of quodlibetal questions by John Peckham, Henry of Ghent, Remigius dei Girolami and John of Naples, in a period of time between the last three decades of the 13th century and the first decade of the 14th. The theological and philosophical starting assumptions appear rather different: if for Peckham all the weight falls on the question of the correctness of the baptismal formulas, Henry is interested in the question of the uniqueness or plurality of the substantial forms in the human compound, Remigius in the hierarchy of the organs, and John in the correspondence between the organs on one side, and between body and soul (as a consequence) on the other. Analogously, as for the conclusions, Peckham, Henry and John of Naples believe – albeit in different ways – that where there are two heads we must presuppose two souls; Remigius has a few more hesitations, granting the possibility that two heads (of unequal capacity and perfection) may correspond to one heart, and therefore to one soul, and above all assuming that where there are two heads, two hearts and two distinct rational souls, one cannot speak of a single body that is truly continuous, but of two bodies welded in an extrinsic way. Particularly worthy of attention is Henry of Ghent’s approach, in which the exception of conjoined twins serves as a kind of anthropological experiment to confirm a doctrine – that of dimorphism – which applies to all human beings and represents the standard condition of humanity. Subverting at least partially the rules of medieval teratology, the monstra cease, at least in this case, to be simply anomalies or exceptions, and become instead explanatory phenomena indicating what is necessary in all other ‘normal’ human beings.