The post-classical (or post-Avicennan, post-Rāzian) genre of the “protocols for dialectical inquiry and disputation” (ādāb al-baḥth wa-l-munāẓara) has its more proximate origins in the famed Risāla of Shams al-Dīn al-Samarqandī (d. 722/1322). The greater part of his conceptions and methodology, however, consists in a streamlining and universalizing of the more strictly juristic dialectic (jadal / khilāf) of his teacher Burhān al-Dīn al-Nasafī (d. 687/1288); and this in turn draws on the highly logicized dialectic of Rukn al-Dīn al-ʿAmīdī (d. 615/1218) and (...) his teacher Raḍī al-Dīn al-Nīsābūrī (d. 617/1220). At the heart of methods in this lineage, and carried forward by al-Samarqandī into the universal ādāb al-baḥth, are three truth-preserving logical relationships critical to the truth-seeking enterprise of dialectic: entailment (talāzum / mulāzama), mutual negation or exclusion (tanāfin / munāfā), and causal concomitance (dawarān). The practical elaboration of these relations reveals a logic in action—a premodern dialogical logic for living disputation praxis. In fact, so critical were these to the dialectical enterprise that al-Samarqandī devoted a specialized treatise entirely to summarizing their defining features and rules, aptly naming it the ʿAyn al-Naẓar, or “Wellspring of Rational Investigation.” In this article, and drawing upon a recently published digital critical edition, I will present an analytical outline of these core logical relations as presented in the ʿAyn al-Naẓar. Then I will address a number of points of interest in this text, grouped under six themes: the potential for cross-disciplinary advancement; notions in discursive development; significant or uniquely contributive formulations; peculiarities of content; signs of an evolving, universalist agenda; and evidence that the ʿAyn al-Naẓar was designed as an aide-mémoire for the active disputant. (shrink)