my judgment, really pursue, neither aspires to dogma, nor is drowned in the waves of politics, but analyzes truth by prompt and reasonable probability.” iv. _Dialectica_, moreover, is the art of effective debate. v-viii. _Logica_ has for its distinctive function to serve as effective instrument. It is not an end in itself. So perverted, it becomes the absurd and deplorable occupation of senility. ix-xi. (866 C) “_Dialectica_, which among the servants of eloquence is most alert and prompt, avails each man according to the measure of his knowledge.... Deprived of the strength of the other disciplines, it is maimed and almost useless; thriving with their vigor, it is strong to overthrow all falsehood, and always suffices at least to reach a probable conclusion.” From my own teachers, to whom I returned years after they had schooled me, I conclude that “as _dialectica_ advances other disciplines, so if it remain alone, it lies bloodless and sterile, and does not engender the fruit of philosophy in a soul not impregnated from other sources.” Of itself it can only despatch issues, not rise to others. xii. _Dialectica_ operates in all disciplines wherever the issue is abstract.[36] It leaves to _rhetorica_ whatever is hypothesis, i.e., whatever involves concrete circumstances: who, what, when, why, how. It makes no address to the public, expects no legal decision. xiii-xv. Though each division of philosophy has its own field of inquiry and its own principles, yet _logica_ supplies methods common to all, as it were theory in a nutshell. A problem in _dialectica_ considers choice and avoidance, truth and knowledge, whether for itself or as aiding inquiry where opinion divides. xvi-xvii. Review of the value and place of Aristotle, of the right use of Porphyry’s Introduction, and of other typical cases in teaching. Bernard (875 D) of Chartres and his followers took great pains to heal the breach between Plato and Aristotle; “but in my opinion they came late and labored in vain to reconcile in death those who differed as long as they lived.” xviii-xix. Certain errors of those who profess Aristotle can hardly be overlooked: the burdening of tender shoulders, the making of Porphyry cover the whole ground, the misinterpretation that simplifies Aristotle by substituting Plato or something remote from both. xx. The last chapter, much the longest, presents Aristotle on genus and species. BOOK III. _TOPICA_