In the previous part we have focused on common-law reasoning by judges and have concluded that there is nothing special about it. In cases unconstrained by precedent, judges use ordinary moral reasoning – the method of reflective equilibrium – and ordinary empirical reasoning to decide controversies and to craft precedent rules for future cases. In cases that are constrained by precedential rules, judges use ordinary deductive reasoning. Reasoning from results in precedent cases rather than from rules, reasoning by analogy from precedent cases, and reasoning from legal principles that emerge from precedent cases have all been shown to be illusory as forms of legal reasoning. The results of such special forms of “reasoning” – special in that they are deemed uniquely emblematic of the legal craft – lack rational force. They are some combination of indeterminate, incoherent, and normatively unattractive. In a limited sense, what appear to be such types of “reasoning” may reflect some useful heuristics for judicial decision making in certain kinds of cases. But they do not qualify as forms of reasoning themselves. Legal reasoning in common-law cases, to the extent it is reasoning at all, is nothing more than ordinary moral, empirical, and deductive reasoning. Legal training is not required to do it, or to do it well.

In this part we turn our attention to another precinct of legal reasoning, that of interpreting canonical authoritative rules promulgated by lawmakers of various types.