18 D. How judges reason

Judicial reasoning is the model of legal reasoning for the whole profession. Its standard moves:1. Deduction — applying the rule to the facts (see 2.4).2. Analogy — "this case is like that case; the reason of that case applies here."3. Distinction — "this case is unlike that one in a legally material respect."4. A fortiori argument — "if the weaker case is true, the stronger is a fortiori true" (if a small harm is actionable, a greater harm is too).5. A contrario reasoning — the opposite of the stated rule implies its negative (a statute authorising X for A implies it denies X to non-A, where the enumeration is exclusive).6. Policy reasoning — choosing the outcome that better serves justice, certainty or welfare, and justifying it as principle.