The subject under consideration here is the knowledge of the principles of jurisprudence, usul ul fiqh. The two studies of jurisprudence and its principles are interconnected. They are interconnected in the same way, as will become clear, as the two studies of logic and philosophy are interconnected. The study of the principles is tantamount to a preparation to the study of jurisprudence, and it is for this reason that it has been named the principles of jurisprudence, for the word usul means roots or principles.