the principles of jurisprudence, whether from the early or later generations, then that is not the case. For discussion of the foundations of jurisprudence and their division into the Book, the Sunnah, consensus, and the exercise of independent judgment, as well as discussion of how legal proofs indicate rulings, has been known since the time of Muhammad’s Companions—may Allah bless him and grant him peace—and those who followed them in righteousness, and the Muslim imams who came after them. They were more firmly grounded in this discipline and the other religious sciences than those who came later. ‘Umar ibn al-Khattāb—may Allah be pleased with him—wrote to Shurayh:

“Judge according to what is in Allah’s Book. If nothing is found there, then according to what is in the Sunnah of Allah’s Messenger—may Allah bless him and grant him peace. If nothing is found there, then according to what the people have agreed upon—or, in another wording, ‘according to what the righteous have ruled.’ If you find nothing, then, if you wish, exercise your own judgment.”

Ibn Mas‘ūd and Ibn ‘Abbās likewise said this, and the hadith of Mu‘ādh is among the best-known hadiths among scholars of legal theory.

If, however, by a legal theorist he means someone who knows “the principles of jurisprudence”—namely, the proofs of the rulings of Islamic law considered in general terms—such that he distinguishes a legal proof from what is not, knows the relative ranks of proofs, and gives precedence to the stronger among them—this being the subject matter of the principles of jurisprudence: knowledge of legal proofs and their relative ranks—then every scholar exercising independent legal judgment in Islam is a legal theorist. For knowledge of legal proofs and their relative ranks is part of what such a scholar knows. Merely knowing the general categories of proofs does not suffice to qualify him to exercise independent legal judgment; he must also know the specific proofs. Whoever knows these specific proofs and distinguishes between the particular instances of