THE TERM “POSITIVE LAW”
When used with respect to the United States Code—as in positive law codification or a positive law title of the Code–the term “positive law” has a special and particular meaning. In general, however, especially in legal philosophy, the term “positive law” is used more broadly. There is overlap to be sure. But the meaning of the term as used generally is not identical to the meaning of the term as used with respect to the Code, and the distinction must be understood to avoid confusion. 
In general, the term “positive law” connotes statutes, i.e., law that has been enacted by a duly authorized legislature.  As used in this sense, positive law is distinguishable from natural law. The term “natural law”, especially as used generally in legal philosophy, refers to a set of universal principles and rules that properly govern moral human conduct. Unlike a statute, natural law is not created by human beings. Rather, natural law is thought to be the preexisting law of nature, which human beings can discover through their capacity for rational analysis.
Within the context of the Code, the term “positive law” is used in a more limited sense. A positive law title of the Code is a title that has been enacted as a statute. To enact the title, a positive law codification bill is introduced in Congress. The bill repeals existing laws on a certain subject and restates those laws in a new form–a positive law title of the Code. The titles of the Code that have not been enacted through this process are called non-positive law titles.
Non-positive law titles of the Code are compilations of statutes
The Office of the Law Revision Counsel is charged with making editorial decisions regarding the selection and arrangement of provisions from statutes into the non-positive law titles of the Code. Non-positive law titles, as such, have not been enacted by Congress, but the laws assembled in the non-positive law titles have been enacted by Congress.
In both positive law titles and non-positive law titles of the Code, all of the law set forth is positive law (in the general sense of the term) because the entire Code is a codification of Federal statutes enacted by Congress, and not of preexisting natural law principles.
 Why is there a specialized meaning for the term “positive law” with respect to the United States Code, and why is this term used despite the potential for confusion with the broader meaning given to the identical term in legal philosophy?
The answer involves a historical solution to a statutory drafting problem. For generations, Congress has used the term “positive law” when it enacts a title of the Code, as such, into statutory law. For example, section 1 of the Act of July 30, 1947 (1 U.S.C. note prec. 1), provides in relevant part: “Title 1 of the United States Code entitled ‘General Provisions’, is codified and enacted into positive law . . . .” (emphasis added). Earlier legislative drafters chose the term “positive law” in order to capture the abstract distinction between a title of the Code that has been enacted, as such, versus a title of the Code that has not been enacted, as such, but that sets forth enacted statutes. More literally, this distinction might be expressed as “enacted title” versus “non-enacted title”, but those literal terms are problematic since they incorrectly suggest that provisions set forth in a “non-enacted title” of the Code have not been enacted. Those provisions have been enacted, but as part of a number of freestanding statutes rather than as part of an enacted (positive law) title. The specialized use of the term “positive law” in this situation captures the abstract distinction between the two types of titles in the Code, and the use of the term in this way is now well established.
 “Positive law typically consists of enacted law—the codes, statutes, and regulations that are applied and enforced in the courts. The term derives from the medieval use of positum (Latin “established”) so that the phrase positive law literally means law established by human authority.” Black’s Law Dictionary 1200 (8th ed. 2004).
Source: Office of Law Revision Counsel