Abstract: That a fact judgment "Being" does not lead to a value judgment "Ought" is called Hume's rule.Later,Hare divided value judgment into moral judgment and normative judgment;Milne then divided facts into non-hypothetical facts and hypothetical facts,and argued that the hypothetical facts contain normativity;Searle further divided fact judgment into brute fact judgment and institutional fact judgment,and proposed that two kinds of value judgment can be derived from institutional fact judgment:evaluative and normative,so as to partially complete the deduction from "Being" to "Ought".Under the influence of Hume's rule and its evolution,there exist a pattern from "Ought" to "Ought",a pattern from "Being" to "Being",a pattern from "Being" to "Ought",and a derivation of negative "Being" and "Ought" in natural law and legal positivism.The evolution of Hume's rule and the exploration of "Being" and "Ought" by natural law and legal positivism reveal the following conclusions:(1) The pure fact judgment completely independent of man is a transcendental existence.(2) A value judgment is a subjective judgment,which only evaluates or normalizes the objective elements that may be involved in the judgment,but does not describe them.(3) There are descriptive fact judgments excluding the subjective factors such as approval,preference,evaluation,acceptance,norm and command,from which value judgments cannot be derived.(4) There are institutional realities transformed by practice,from which value judgments can be derived.(5) In practical reason,fact judgment and value judgment are not completely divided and can be accommodated.

Key words: Hume's problem, natural law, legal positivism, moral judgment, normative judgment, institutional fact