What was Dante's interpretation of the third Aristotelian disposition of Nicomachean Ethics 7, which he calls ‘la matta bestialitade’ and how does it function in the structure of the Inferno? Correlatively, what range of meaning did Dante assign the second disposition, ‘malizia’? The problem is difficult at best and, from a modern point of view, apparently literarily unrewarding. What is more, after a long tradition of scholarly discussion and dispute a kind of consensus has emerged. With the solution which it proposes most are willing to rest content and indeed many simply take its correctness for granted. It is the thesis of this study that the consensus is based on an improvisation and that the high probability of an alternative solution can be effectively demonstrated. Underlying this is the conviction that this is not a scholarly quibble, of interest only to the ‘experts’ or merely a matter of interest for the history of ideas. Rather it is a problem with profound significance for the total structure of the Inferno both intellectual and literary.