Immanuel Kant 
The Science of Right 

The Science of Right has for its object the principles of all the laws which it is possible to promulgate by external legislation. Where there is such a legislation, it becomes, in actual application to it, a system of positive right and law; and he who is versed in the knowledge of this system is called a jurist or jurisconsult (jurisconsultus). A practical jurisconsult (jurisperitus), or a professional lawyer, is one who is skilled in the knowledge of positive external laws, and who can apply them to cases that may occur in experience.