反对逻辑多元论:来自规范性的论证

Review of Logical Pluralism:An Argument from Normativity

根据毕奥和雷斯托尔的逻辑多元论,有多少种后承关系就有多少种逻辑。除了从形式性和元语言地位发起的诸多反驳外,这种逻辑多元论还面临来自规范性的两个反驳论证。第一个论证涉及后承与真理之间的关系:如果从真理的角度来理解后承,那么逻辑多元论必然蕴涵真理多元论。这种看法尽管有许多支持者,但也为与真理相关的规范性带来有问题的后果。第二个论证也涉及规范性。逻辑多元论必然蕴涵关于规范性的多元论,它使得逻辑的规范力变得无能为力。宣称逻辑不具有规范性并不能成功反击上述规范性反驳,因为有效推理相关的规范性主张是关于有效性的主张所预设的,对使用逻辑而言是必不可少的。此外,如果关于逻辑的纯粹描述性的主张意味着逻辑与推理无关,那么相当于承认逻辑虚无主义。规范性论证也可以扩展到反对逻辑多元论的知识论证,逻辑多元论将得出我们从演绎中获得的知识是碎片化的,如果一个人不是知识的相对主义者,那么他就必须拒绝导致这一后果的逻辑多元论。

According to Beall and Restall’s logical pluralism,there are as many logics as there are consequence relations.In addition to various objections from formality and the status of the metalanguage,this kind of logical pluralism faces two objections from normativity.The first has to do with the relation between consequences and truth:if consequence is understood in terms of truth,then logical pluralism entails truth pluralism,which has a number of partisans,but which has problematic consequences for the normativity associated to truth.The second argument also bears on normativity:logical pluralism entails pluralism about normativity,which renders the normative force of logic powerless.Claiming that logic is not normative does not successfully refute argument from nomativity,because normative claims related to valid reasoning are presupposed by claims about validity and are essential to the use of logic.Moreover,if purely descriptive claims about logic imply that logic is irrelevant to reasoning,they amount to an admission of logical nihilism.The normativity argument could also be extended to knowledge argument against logical pluralism,which could entail the knowledge we obtain from deduction is fragmented,and if one is not a relativist of knowledge,then one must reject the logical pluralism leads to this consequence.