The debate between Zhuangzi and Huizi has profound epistemological significance, however, the main body of their debate comprises logical inferences and refutations. Therefore, this paper mainly focuses on the logical aspects of the debate. Some scholars have suggested that Huizi’s argument is self-contradictory; however, in fact, based on such evaluations of Huizi’s argument, we can conclude that Zhuangzi’s logic is also self-contradictory. By utilizing modern logical analysis tools, this study reveals what and how the propositions and inferences contained in the (...) language of the debate are articulated accurately and strictly. Moreover, by elaborating on the implicit premises omitted by Zhuangzi and Huizi, the actual logical process of the debate can be restored, and the logical fallacy of clandestine change of argumentative issue are revealed. This study presents clear modern logic analysis of the debate; it can also provide a more reliable logical basis for the discussions of Zhuangzi and Huizi’s related philosophical thoughts. (shrink)

The non-alethic systems N1 of da Costa and A of Grana are both paraconsistent and paracomplete. Based on them, a multi-agent doxastic logic NADK can be obtained by logical expansion. The soundness and completeness of NADK are proved and its special theorems are also presented. In this logic, the belief version of the laws of contradiction and excluded middle, as well as the principle of explosion are all invalid. Therefore, it may provide a reliable logical basis for any theory which (...) has paraconsistent or paracomplete epistemic conflicts, such as true contradictions, true contrarieties, and belief paradoxes. We also explain in detail how a non-alethic doxastic logic provides a reliable logical basis for tolerating these three types of epistemic conflicts. The present paper is the deepening and development of system N1 and A. (shrink)

Aristotle discovered the law of contradiction more than 2000 years ago. Since then, this law has been regarded as one of the basic principles of logic. Aristotle considered this principle to be 'the most indisputable of all beliefs,' but nearly half a century ago, it began to be criticized. The voice of criticism came from a philosophical logic - paraconsistent logic. This study analyses in depth the specific properties of the positive logic plus approach, non-adjunctive approach, and relevant approach of (...) paraconsistent logic and presents three definitions of the law of contradiction. It also shows that there are two types of the law of contradiction in C-logics and that the law of contradiction with classical negation is valid in them. Furthermore, this study proves that the law of contradiction with classical negation is also valid in a non-adjunctive approach and explains the reason this law cannot be deduced in some relevant logic systems. Based on these, we can clarify what type of the law of contradiction is questioned by paraconsistent logics and thoroughly reveal the exact meaning of 'the law of contradiction is invalid' in paraconsistent logics. (shrink)