This paper deals with the two fields of philosophical logic and philosophy of logic The author holds that although there are different meanings of the term of philosophical logic in Anglo--American philosophy and logic,in the normal and common meaning it refers to modern logical branches which are different from classical logic or standard logic.
It come from the combination of the scienceof error and classical logic theories and contemporary logic theories. It look for reasonsof errors , influence scope of errors and approaches of avoiding and eliminating errors.
This paper, in accordance with the theory of contemporary logic as well as the nature of formal logic, makes an analysis of some aspects in several definitions for deductive reasoning, and presents a relatively comprehensive and accurate definition capable of generalizing the essence of deductive reasoning: (1) deductive reasoning is one in which the determinative scope of the concision does not go beyond that of the premise;
Based on many years' experience in teaching, the author suggests some concrete methods of readjusting the contents of traditional and modem logic courses. Two pieces of advice are also mentioned on the practical issues in connection with students' study.