The common law is created by human judges, and that they decide those cases according to the legal values they hold.
“Formal” judges decide cases the way earlier judges decided them, just because those judges decided them that way. These judges value stability and certainty in the law. They don’t care whether the law is right or good; they want it to be predictable. The most formal of these judges think of law as a system of narrow and consistent rules from which they construct rules they hope can be mechanically applied by the judges ruling after them.
This demands the impossible, for no two cases are, or can ever be, identical. Every case is infinitely similar and infinitely different from every case that has ever been decided or ever will be decided, and so a judge must decide which of the infinite similarities and differences that exist between any two cases actually matter to how she makes her decision in the case before her. That requires judgment.
Other formal judges might also look backwards for their answers to how to decide a case, but to a past that produced not narrow legal rules, but broad legal principles, such as liberty and equality.
On the other hand, “Substantive” judges care about creating law that is right or good, whether that law is stable or not. They don’t value the past because they think law ought to express a community’s present sense of justice. They believe that judges must keep law in step with contemporary public values, prevailing understandings of justice, morality, and new scientific discoveries. They don’t want issues settled; they want them settled to produce moral law or good public policy.
Substantive “policy” judges who try to predict the future impact of their rulings think law should achieve important social goals, such as economic growth, national unity, or the health or welfare of a community. Substantive “principle” judges supremely value morality. They want to do what’s right, and they may derive what’s right from almost any source, including religion, ethics, economics, politics, and what their mothers told them.
Next: The Capacity to Have a Legal Right
