 The study of the nature of law is distinct from these. It can be divided into two principal inquiries, corresponding to the division between the “constituents” and “sources” discussed in sections  3  and  4.  The first inquiry examines what determines or grounds the content of laws in general, within a legal system. For instance, is the content of a law exhaustively determined by the statutes recorded in the legal code? Or is that only a part of what determines the content of a law? Other candidate contributors to the content of a law are historical judicial interpretations, jury decisions, patterns of practices, legislative actions and intentions, executive statements, general legal principles, and moral principles. Hart (1961) casts this question as the inquiry into the “rule of recognition” in a legal system: that is, what conditions a proposition needs to satisfy in order for it to be a law (see also Dworkin 1967, 1978, 1986; Greenawalt 1986; Shapiro 2007, 2009).