Anselm’s Cur Deus Homo, part 6.
To Anselm’s list of the ways in which the Incarnation is fitting, Boso responds by invoking once again Anselm’s theology-as-art metaphor, stating that Anselm’s account amounts only to so many “beautiful pictures, as it were” (pulchra et quasi quaedam picturae suscipienda sunt), but that without “a solid foundation upon which they rest, they do not seem to unbelievers to suffice for showing why we ought to believe that God was willing to suffer these things of which we are speaking” (ch. 4). Instead, Boso insists that “first of all we must exhibit the truth’s firm rational foundation, i.e., the cogent reasoning which proves that God should or could have humbled Himself to undergo those things which we proclaim,” and only this has been done should such “considerations of fittingness … be set forth as pictures of this body-of-truth.” According to Boso, showing the aesthetic fittingness of a belief is one thing whereas demonstrating its rational necessity is something else entirely, a view that some scholars have interpreted Anselm to share in and therefore as determining the structure of the subsequent argument of the dialogue. As we have already seen, however, the aesthetic perspective of the Cur Deus Homo is one that Anselm commits himself to before the fictional framework of the dialogue even begins, and as I further argued, the whole criterion of aesthetic fittingness is one that is indissociably bound up with his view that such theological investigations can at best approximate an otherwise unfathomable truth and therefore only ever attain an at most provisional kind of necessity or certainty. Corroborating this interpretation, moreover, is that in his reply to Boso, Anselm says nothing that would concede to Boso the validity of his distinction between mere theological word-pictures on the one hand and putatively more “rational” considerations on the other. Instead, he merely reasserts his principle that fittingness comes with it its own form of necessity: “Do not the following considerations,” Anselm rejoins, “seem to constitute a very cogent argument for why God ought to have done those things about which we are speaking?: viz., that the human race—His very precious work—had utterly perished; and it was not fitting that God plan for man should be completely thwarted; and this plan of Gods’ could not be carried out unless the human race was set free by its very Creator.” In the following chapter, finally, it is not Anselm who yields to Boso’s distinction between necessity and fittingness, but in his plaintive question as to whether there was not a “much more tolerable” (multo tolerabilius) way in which this liberation might have been accomplished, it is Boso who yields to Anselm’s identify of necessity with fittingness (ch. 5).
 Sandra Visser and Thomas Williams express this view in their critique of Brian Leftow’s interpretation of the argument of the Cur Deus Homo along aesthetic lines when they argue that, for Anselm, “appeals to what is fitting are superfluous from a strictly philosophical point of view; Anselm does not use them to establish the truth of the Christian account of redemption, but to show the attractiveness of that truth once it has been established. Indeed, Boso insists from early on in Cur Deus Homo that Anselm not appeal to considerations of fittingness as though they could serve as independent philosophical considerations in favor of the Christian account of redemption. Anselm tries to use such considerations in response to Boso’s initial statemnt of unbelievers’ objections to the Christian account, but Boso immediately rejects them as unpersuasive… In deference to Boso’s complains, Anselm does not raise the ‘poetic parallels’ that Leftow cites from Cur Deus Homo until after he has established that it is necessary for God to become incarnate and lay down his life as recompense for human sin.” Visser and Williams, Anselm, 219. Counter to Visser and Williams’s latter claim, however, and in addition to the argument I make presently, Anselm continues to appeal to considerations of fittingness throughout the remainder of book one of the Cur Deus Homo.