But here’s the secret most 1Ls discover around 2 AM:
Every time you say, “That’s not fair” (Natural Law), “That’s not the rule” (Positivism), or “That’s not how this judge rules” (Realism), you are doing legal theory. The only choice is whether you do it (consciously, rigorously) or badly (by instinct, with contradictions).
At first glance, the answer seems simple. Jurisprudence is the philosophy of law. Legal theory, then, is the set of frameworks we use to ask why we have law, what makes a law valid, and how judges should decide cases.