D. About the Baptism of a Receiver whose Unicity is in Doubt

52. About the fourth member of the distinction [n.31] I say that if time can be had for discerning whether the monstrous birth is simply one person or two, diligent investigation should first be made about this before it is baptized. And investigation can be made either from the parts of the body (for example if there be two heads or two spines in the back), or there is the more principal indication of hearts.

53. But this [indication of hearts] cannot easily be clear while it is alive.

54. But neither can the sign about two heads be altogether certain, because it would be possible for some chamber of the womb to be divided through the whole of it, besides at the top, and then the parts of the seed, falling through the womb’s diverse openings, would come together in the whole lower part and be distinct in the top part; and two heads would be formed there although, however, the rest of the matter would only be sufficient for the formation of one person.Scotus seems to be following an example discussed more fully by Henry of Ghent, Quodlibet VI q. 14. ³⁵

55. Briefly, the clearest sign for discrimination is through act of intellect and will: for, if there are two souls, it is not necessary that one know whatever the other knows, nor that one wants what the other wants; yet rarely or never does it happen that there are two souls without two heads or two principal parts of the head, though not conversely.

56. And if in any way a diversity of intellects in understanding can be detected (for example, that by some sign it were detected that the same thing was known and not known), or if a diversity of wills could be detected (for example, that there was a willing there and a refusing of the same thing), without doubt should one hold that there were two souls there.

57. But this can only be judged about an adult monstrous birth, of the sort posited to have existed in France, possessing two heads, one of which expressed a refusal of that for which the other expressed a willingness; for one wanted to be continent and live soberly and the other to be lascivious and to feast; and when one would go to extremes in eating through its mouth, the other would exclaim it was bloated.The story is in Henry of Ghent, ibid. ³⁶

58. About this monstrous case I say that if certitude can be had, and if there are parts about which it is plain that they belong to distinct persons, each part should have water poured on it separately, with repetition of the form [of baptism] in the singular on each of them. If certitude cannot be had, it is to be baptized, at least on those parts that belong principally to one of them, with the form in the singular; and second those parts are to be washed that do not seem principally to belong to that first one, and this with the form to be observed in those cases where there is doubt, which is set down in Decretals III tit.42 ch.2, Gregory IX [“Where there is doubt if they have been baptized, let them be baptized with these words, ‘If you are baptized I do not baptize you; but if you are not yet baptized, I baptize you etc.’”].