Research On The Existential Presupposition In The Reasoning Process Of The Categorical Proposition

This paper is to investigate the existential presupposition in the reasoning process of the categorical proposition.The existential presupposition in the reasoning process of the categorical proposition can reflect the obvious difference between traditional logic and modern logic.When the traditional logic deals with the equivalence reasoning,judgment deformation reasoning,categorical syllogism reasoning of four kinds of categorical propositions,the subject and predicate of a proposition are non-empty,that is,the object referred to by the term in the proposition is assumed to exist.The existential presupposition is the default premise for traditional logicians to deal with the reasoning of the categorical proposition.Modern logic can more accurately depict the formal structure of categorical proposition with the introduction of logical quantifiers,it thus can clearly distinguish the existential import of proposition from the presupposition of existence behind the reasoning process of the proposition user.The main contents and contributions of this paper are fourfold:(1)Focusing on the various misunderstandings and confusions about the existential import and existential presupposition in the domestic and foreign works of literature,this research defines and clarifies two key concepts of existential import and existential presupposition of the categorical proposition,which also distinguishes the semantic and pragmatic aspects of the two on the basis it.It is found that the existential import is the logical meaning of the proposition determined by the propositional form,which directly reflects the relationship between propositional expression and its meaning in formal logic.While existential presupposition is the pragmatic meaning of proposition appended by the proposition user,which is actually a concept of logical pragmatics that is closely related to the subject.So,these two have different properties.(2)Through the investigation and deductive proof of differential equivalence reasoning,contrariety relationship reasoning,subcontrariety relationship reasoning,conversion peraccidens reasoning,conversion contraposition reasoning and weak reason ing of nine categorical syllogisms,it is concluded that universal propositions have no existential meaning,while particular propositions are of it.In the reasoning process of the categorical proposition,it is necessary to introduce proper existential presupposition when it comes to deducing corresponding particular proposition from universal proposition to ensure the validity of reasoning.And there is no need to introduce presupposition of existence in the reasoning form of categorical proposition except for it.(3)In addition,this study clarifies the confusions of the existential presupposition in prior research by distinguishing between the existential import and the existential presupposition.Because of the absence of clarifying the semantic concept and the pragmatic concept,prior studies in the reasoning process of the categorical proposition mixed the existential import of propositions and the existential presupposition appended by users.This paper proposes a solution to this problem.(4)Finally,this paper studies the related problems in the basic teaching of logic and discusses the problems in the logical textbooks dealing with the existential presupposition.When referring to the existential presupposition of the categorical proposition,large amounts of logic textbooks mistaken the existential import of propositions as the existential presupposition appended by users,which resulted in various improper interpretations and theoretical inconsistencies.This paper has clarified this problem.