Hence, we talk about the logic of common knowledge, but also talk about some of the dialectical logic of knowledge, which is an unavoidable problem must be told the students, an important form of reasoning, but only form of reasoning is not enough, in the form of reasoning can not be resolved place, need to use dialectical reasoning so that students analyze the case that knowledge is not simply a logical application, not prone to "the law of justice is a variable" and other negative views. Law without logic, the rapid development of the legal requirements of each legal person of logic, application logic, to find legal logic. Legal logic, or a mature discipline, it requires a mature legal logic scholars and academics work together, this is also a legal development.