Plato suggests powers exercised by a ruler are governed by customary and community rules. Decisions are made by the minds of the rulers and their delegates. Humans have some innate knowledge of what is important and good in human life and because of this, we should not be constrained by laws and rules but by what our minds tell us what is right and just in the circumstances.
The laws do not expressly provide on how to deal with this specific situation and judgment must then be made on moral principles. Permanent laws are incompatible with changing demographics and technology. Laws must change at the same pace with the rest of society to maintain society's current perspective of justice and righteousness, but time delays in passing laws precludes this. Still now, the public waits for tougher dog laws to be passed on pit bulls and others alike. Even worse, there is no guarantee administration will be efficient. Here, Plato argues, rules fail to meet the differences of time and there is a need for rulers to exercise discretion as it encourages efficiency.
Where rules fail to take into account of specific, exceptional cases, Aristotle claims, equity should apply. Judges should correct errors of the law, rising from oversight by the lawmakers, given there are rules to be corrected in the first place. This is therefore, an argument to being ruled by laws. He favours rule by democracy where government by a collective of good men is better than being ruled by an absolute king. Decisions ought to be made by a democratically-elected assembly. Unlike Plato's idea of 'permanence', offices and positions will be rotated; enforcing the idea that everyone is equal and everyone should both rule and be ruled.
The practice of using legal precepts to decide disputes was criticized by American Legal Realists as either redundant or pernicious. Disputes, it is said, should be decided justly. Where legal precepts dictate the same outcome as that of justice, and then legal precepts are redundant--acting justly will achieve the same results as following the precept. Where legal precepts recommend a different result than that recommended by justice then following the rules are pernicious. The result is, in the words of Jerome Frank, "injustice is according to law." (Frank, 1936) Most people are of a similar opinion when confronted with what appears to be the "unjust" application of a rule to a particular situation.
One assumption underlying this objection is that, because they are formulated before a dispute arises, legal precepts cannot take into account the specific facts of a dispute that may argue in favour of a different "just" result than that recommended by the legal precept. Only after the fact can we know enough about the actual dispute to do real justice between the parties. As Frank argued,
The judge, at his best is an arbitrator, a "sound man" who strives to do justice to the parties by exercising a wise discretion with reference to the peculiar circumstances of the case. He does not merely "find" or invent some generalized rule which he "applies" to the facts presented to him. He does "equity" in the sense in which Aristotle--when thinking most clearly--described it. "It is equity," he wrote in his Rhetoric, "to