Defeasible Reasoning in the New Essays

VARGAS, EVELYN

Hannover

Congreso; X. Internationaler Leibniz-Kongress / X International Leibniz Congress ?? ad felicitatem nostram alienamve; 2016

Leibniz Gessellshaft

Thescholastic goal of demonstrative scientiain the natural sciences was gradually abandoned in favor of the experimentalknowledge that was being generated by scientific practice. In short, a radicalrevaluation of knowledge claims that do not aim at achieving absolute certaintytook place throughout the seventeenth century. Indeed, Leibniz was not alien tothese reconfigurations of what counts as knowledge. But the scope and nature ofhis commitment to admit the less than certain may be difficult to specify. Onthe one hand, early modern rationalists are usually characterized as therepresentative figures of infallibilist and foundationalist positions, whilethe new conception knowledge as warranted belief is intrinsically fallibilistsince justification does not entail truth (i.e., a belief can be justified andfalse). Also, although historians of probability have been inclined to includeLeibniz in their accounts, these scholars often emphasize the similarities ofLeibniz?s attempts to estimate the uncertain with what is now regarded as theclassical interpretation of probability, according to which probability is anepistemic notion rather than a character of phenomena and natural processes.But to locate Leibniz in the role of precursor of ideas that only later becamerigorously formulated may be of little interest or, as I expect to show,misleading. Furthermore, the meaning of probability in the seventeenth centuryis problematic by itself and combines inherited traditions and conceptualnovelty, subverting any attempt to reduce the various uses of the term into onesingle notion. A better understanding of Leibniz?s views on the less than certainrequires an examination of his uses of the term in connection to thedisciplinary realms within which they were discussed and defined. Byconsidering the different disciplinary contexts, and their specific aims, wewill be in a better position to identify the distinctive features of Leibniz?sconception in contrast, but also in connection to, the received views onprobability and opinion. In the following sections, I will hold that forLeibniz, ?probable? qualifies a type of arguments that must be distinguishedfrom deductive reasoning. Also, by criticizing Locke?s views in the Nouveaux Essais, the imaginary dialogueoffers the opportunity to understand Leibniz?s long-term reflections on theissue in contrast to more traditional approaches.  One important point of disagreement is Locke?sview that probable inferences only have the appearance of an inferentiallinkage; their resulting consequence is not certain and therefore the object ofthe belief remains unknown. For Leibniz, if the foundation of probableinference is its ?vraisemblance? or conformity with truth, probablebelief may be regarded as a form of knowledge.