 There are, however, two major complications that hinder any direct assessment of the Divine Comedy’s treatment of the nature of philosophy. First, there is the question of the how to interpret the explicit doctrinal claims of the various speakers in the Divine Comedy. Purgatorio 16, for instance, introduces Marco the Lombard on the terrace of wrath. Marco’s speech to Dante’s pilgrim touches on a variety of philosophical subjects, including a refutation of astral determinism. But the culminating lines of his speech do little more than offer a brief summary of the political philosophy espoused in Convivio 4 and Monarchia. Specifically, Marco offers the following diagnosis of the cause of civil strife in the Italy of Dante’s day (Purg., 16.106–12):