A recurring question in the philosophy of law is the relationship between law and morals. The Hart/Fuller debate famously illustrated this: Hart thought that law and morals were conceptually separate, and that a “bad” law was just as much of a law as a good one. Fuller disagreed, and thought truly bad law could not be seen as law at all.
With that background, a friend passes along a recent exchange between his sons that well encapsulates Hart’s positivist position:
William: Daddy, why didn’t we have lunch today?
Henry: We did have lunch, William. Remember we had that chicken?
William: But I didn’t like it.
Henry: But it’s still lunch.
William: Oh. Yeah.