This dissertation explores how antiquity and some of its early modern admirers understand the notion of certainty, especially as it is theorized in Quintilian's Institutio Oratoria, a first-century educational manual for the aspiring orator that defines certainty in terms of consensus. As part of a larger discussion of argumentative strategies, Quintilian turns to the “nature of all arguments,” which he defines as “reasoning which lends credence to what is doubtful by means of what is certain” (ratio per ea quae certa (...) sunt fidem dubiis adferens: quae natura est omnium argumentorum, V.10.8). These certainties, he later specifies, include not matters of scientific demonstration or objective fact, but the agreements of various communities: the laws of cities, local customs, and other forms of consensus. As the foundation of persuasive rhetoric, these consensus-based certainties situate argumentation as the practice of crafting agreements rather than demonstrating necessary conclusions. Taking as its point of departure Quintilian's novel understanding of certainty, this study looks to some of Quintilian's intellectual forebears as well as his later readers to show how his work is both a nexus of earlier intellectual developments as well as an important inspiration for later accounts of certainty, even into the early modern period. After illustrating in the first chapters of this dissertation how Quintilian's manual incorporates elements from Aristotelian notions of dialectic and rhetoric as well as from Ciceronian skeptical approaches to epistemology, I show how Quintilian's curriculum for the orator shapes the thought of Italian humanists, especially that of Lorenzo Valla (1406–1457), a reformer of scholastic logic and dialectic, and Giambattista Vico (1668–1744), an influential Neapolitan jurist. Adopting Quintilian's rendering of certainty as a matter of agreements and conventions, these later authors elaborate their own novel approaches to various fields—including law, language, and logic—through this ancient understanding of certum. Contrary to modern notions of certainty as objective or scientific fact, Quintilian's humanist readers continue to root this concept in consensus, both within the courtroom and without. (shrink)

Negotiation research primarily focuses on negotiators? interests in order to understand negotiation and offer advice about the prospective outcome. Win-win outcomes, i.e., outcomes that serve the interests of all negotiating parties, have been established and promoted as the ultimate goal for any negotiation situation. We offer a perspective that draws on Aristotle's philosophical program and discuss how the outcome is not defined by the parties? interests, but by the intersubjective validity of claims, which can essentially be treated as representative of (...) the ?truth.? (shrink)

Aristotle's conception and use of ta endoxa are key points to our understanding of Aristotelian dialectic. But, nowadays, they are not of historical or hermeneutic importance alone, as, in Aristotle's treatment of endoxa, we still see a relevant contribution to the modern study of argumentation. I propose here an interpretation of endoxa to that effect: namely, as plausible propositions. This version is not only defensible in the Aristotelian context, it may also shed new light on some of his assumptions and (...) methodological shortcomings – e.g. concerning the 'plausible/implausible' pair –; finally, it will even enable us to show certain basic hints and guidelines, advanced by Aristotle's study of endoxa, which still serve nowadays to orientate our studies of argumentation from the angle of a theory of plausible argument currently under construction. These hints and guidelines suggest a pragmatic, gradual and comparative discursive concept of plausibility, and point, in particular, towards the reasonable dealing with, and weighing up of, differences of opinion within this frame of reference. (shrink)