Evaluating the Subject of the Principles of Jurisprudence according to the Logical Rule "The Subject of Every Field of Knowledge Is That Whose Essential Properties Are Discussed in That Field"

The rule "the subject of every field of knowledge is that whose essential properties are discussed in that field" is stated by logicians in logic and discussed in more detail in the discussion of the subject of a field of knowledge and its essential properties, and finally it is used in other fields, such as philosophy and medicine. The question is whether this rule embraces all fields, including the principles of jurisprudence. What is certain is that with the expansion of disciplines, there have emerged branches of knowledge that are not included in the scope of this rule because they discuss topics that are -logically speaking- beyond the essential properties of the subject of that branch. One of these disciplines is the principles of jurisprudence. According to this rule, the scholars of this filed hold mixed opinions in determining its subject and have presented different ideas such as: considering the unity of issues based on the unity of the goal, denying that the issues are the essential properties of the subject, and offering a new reading of the essential properties. In this article, we are going to explain the origin of this confusion of opinions and we argue that ignoring the scope of this rule and other discussions related to this rule in logic, has doubled the effort of the experts of the principles of jurisprudence in justifying their opinion.