2. Scotus’ own Opinion

65. As concerns this article [n.56], therefore, a distinction can be drawn about the medium; for just as - between an agent and its action or effect - something can be posited to be medium either as the ‘what’ (as the proximate agent between the remote agent and the effect) or as the ‘by what’ (as the form of the agent), so between the recipient and the received a double medium can be posited, a ‘what’ and a ‘by what’. For just as something can be the reason of acting for something, so can something be the reason of receiving for something; and the medium with respect to the reception of an accident can sometimes be the proper form of the receiver, just as a subject first receives its proper accident through its proper form (as through its proper reason of receiving).

66. As to the issue at hand it can be said that, in the passive assumption of human nature into the Word, there was no medium as ‘what’ between the Word and the whole human nature, but the whole human nature was assumed immediately.

67. The proof is as follows, that what, if left to itself, has first the capacity to be a person in itself, is first a person in another when it is assumed, because the divine personhood supplies the place of the thing’s own personhood; the whole human nature, if left to itself, and not a part or parts of it, is in this way first and immediately able to be a person; therefore etc.

68. The proof of the major is that the whole human nature is a person in another or by another in the same instant of nature in which, if left to itself, it would be a person in itself; for it is not of a nature to be assumed before that instant (because it was not a singular nature before that instant), and it is not assumed after that instant (because after that instant it would be person by itself).

69. The proof of the minor is that in the same instant of nature in which the matter or the form precedes the whole, neither the matter nor the form is of a nature to be a person; but when the whole nature exists from these united parts, then first is the thus united whole a person, if it is not impeded by the assumer.

70. Speaking of medium in the second way [n.65], namely as ‘by what’, one can concede that the soul is the medium in the assumption by the Word - and this with respect to the whole nature, because the soul is the formal idea of this nature, whereby the nature is capable of being united (just as the soul is the formal idea whereby a man, not only as efficient principle but also as proximate subject, is formally capable of laughter); and just as the soul is the form of the subject, so it can be the form that constitutes the nature, and yet it is the proper reason for the whole nature of receiving this union, because it is the proper reason constituting the whole that is receptive of the union. Nor on this account need the soul be first assumed as the ‘what’, just as neither is the soul capable of laughter as the ‘what’, although it is the ‘by what’ a man is capable of laughter.

71. And by reason of this idea of being medium can the whole nature truly be said to be assumed through the soul, such that the ‘through’ states with respect to the predicate the circumstance of quasi material cause, although, with respect to what is determined through the soul, it states the formal cause -just as also in the statement, ‘man is capable of laughter through the rational soul’, the form of the soul is indicated to be quasi material with respect to the predicate. In this way too the soul can be conceded to be the medium between the flesh and the Word, because the soul is the total form of the nature assumed first and is, for this reason, the medium ‘by which’ the whole nature is what it is and is assumable and is assumed; and the soul is hereby itself assumed, because it is part of the nature assumed first. Thus too is the flesh in its own way assumable and assumed.