By comparing the non-demonstrative inference as discussed in Relevance Theory and abductive inference, this article applies the later Peircean logic of abduction and Hobbs Interpretation as Abduction to demonstrate that pragmatic reasoning is actually the specific application of abductive inference in utterance.

By examining vivid examples in daily communications, the thesis aims at expounding the speaker s communicative strategies by using PA and focuses more attention on how the hearer applies non-demonstrative inferences to grasp the speaker s communicative intentions from the perspective of relevance theory.

The text first values logically whether argument is valid by deductive and inductive standard, and sets forth the validity of formal argument in system and the validity of extra-systematic informal argument, in order to provide discriminating criterion for discussing the validity of formal argument in system and the extra-systematic .

With a method of regulation-gap analysis, the paper analyzes the purpose description on the policy feasibility study.

Listed companies should attach great importance to the feasibility study of new issues,and the authorities should strengthen the regulation of new issues by listed companies and establish and perfect the restraint mechanism.