The correct answer is "is the philosophy of law."
is a noun that means: The science or philosophy of law. A body or system of laws.
1620s, "systematic knowledge of law," from French jurisprudence (17c.) and directly from Late Latin iurisprudentia "the science of law," from iuris "of right, of law" (genitive of ius; see jurist) + prudentia "knowledge, a foreseeing" (see prudence). Meaning "the philosophy of law" is first attested 1756. Related: Jurisprudent; jurisprudential.
The science of jurisprudence regards the state and power as the ancients regarded fire--namely, as something existing absolutely. But for history, the state and power are merely phenomena, just as for modern physics fire is not an element but a phenomenon.
-- Leo Tolstoy, War and Peace, translated by Nathan Haskell Dole, 1899