Abstract

Based on the strict definitions of concepts, such as deduction, the deduction rule and the deduction system, the form axiom, the substantive axiom, this article clearly shows the essence of the deductive reasoning, namely “Related attribute and the related restriction relations, which are conveyed in what the main concept of the deduction refers to, must be contained in those conveyed in what the premise proposition refers to”。Then puts forward the theorem “contradiction can not be derived from the strict deduction system”, and gives the proofs.