Talking About Logical Consequence And Logical Truth

From the view of philosophy of logic,logic is studying the relation of consequence and valid inference. The centre of valid inference is that a certain statement is able to follow (from) other statement or statements. In other words, if we accept that some statement or statements is (are) true, then we assert that other statements are true too. This relation about the following is taken as relation of consequence. Particularly if this relation can be guaranteed by the forms in which these statements are put and be the logical necessity, then we say that the conclusion is the logical consequence of the premises.As T.Reid says, it is an important concept in the logic, especially in modern logic. And only when you totally understand and master the problem of logical consequence and its related questions, can you truly learn modern logic well. Therefore, it is important to study it.The article, based on development of history of logical consequence, systemically discusses the problem of logical consequence and other problems related by comparatively researching other basic concept of logic closely related to logical consequence. Firstly, it reviews the different definitions of logical consequence in detail, sums up all ways in researching logical consequence and points out some falsity in all ways. And then by analyzing the extension and intension of logical consequence, it indicates the fundamental character of logical consequence is preserving truth.Based on this, this article deeply analyzes other two logical concept closely related to logical consequence: logical validity and implication. And it points out that varied understanding of logical validity and implication results in different theories of logical consequence.And the article discusses logical truth, as a special example of logical consequence. By historically studying logical truth, it summarizes some theories about"true"and points out that logical truth is necessary and relative.Finally, this article illustrates the basic character of logical consequence in classical logic, expounds that some logicians criticize the classical view of logical consequence, and points out this dissatisfaction arises from logicians'discussion to the theory of logical consequence and makes them put forward many new logical consequence theories, and promotes the development of the logical consequence theory and makes logical consequence theory perfectly.