Skip navigation

At the heart of all legal reasoning lie two methods of argument. The first, and paramount, method is the argument from authority. The second is the application of first principles, wielded as a yardstick to measure the diktats of authority and mitigate its harshness.

The form of an argument from authority is simple: (a) Source A (e.g. a decision the Hong Kong Court of Final Appeal) says that the Proposition P is true, (b) Source A is a binding source for Proposition P or, if not binding, is a highly authoritative and persuasive source and (c) therefore Proposition P is true.

There are two significant refinements made in practice. The first refinement focuses on comparing the facts before Source A and the case being decided to see if they are similar or can they be distinguished.

The second refinement focuses on the nature of Proposition P to determine whether it was necessary for the court to reach its conclusion in Source A (i.e. Source A was speaking only hypothetically when it laid down Proposition P rather than in its decision making capacity. This second method is particular to the common law world, which divides case law into the rationes decidendi (the reason for the decision) and obiter dicta (things said ‘in passing’ on the way to reaching the rationes)).

To my mind there is a third refinement. The most common counter to any argument from authority is that the source was not an authority in the relevant area (e.g. whilst we accept Albert Einstein’s views on general relativity, we should not accept his views on quantum physics because Einstein is an expert on general relativity, not on quantum physics).

Applied to the legal sphere, this counter-argument is based on three premises: firstly that institutions, such as courts, have no inherent expertise, secondly that it is the decision of judges (not courts) that decide cases, and finally when a judge leaves the court his expertise is irretrievably lost. In this sense, any judicial decision is not the decision of a court; it is the decision of a particular judge or judges hearing the case.

This opens up a simple challenge to propositions laid down in any judgement: the judge was not an expert on the area of law in question.

In reality it would be a brave lawyer who suggested that the decision of a Chancery judge sitting in an Admiralty case should not be followed because the judge was far outside his own particular specialisation and knee deep in another equally intricate specialisation. Similarly the decision of a judge might be challenged on the basis that, even though the judge went on to become an expert in that field, he had no particular expertise in that field at the time when the decision was made.

It is instructive to note that almost no modern lawyers have the necessary knowledge of legal history to sustain such a challenge. We have long since forgotten whether a particular member of the bench plied his trade on the commercial list or the construction and arbitration list. The chance that a modern practitioner would know if a 19th Century member of the House of Lords specialised in criminal or civil work is miniscule. Law schools don’t teach these things because it is ‘irrelevant’ to the art of legal reasoning.

Why should this be the case? Why is the most commonly deployed argument against the argument from authority completely decried in the one field where authority is the primary mode of reasoning?

I believe the answer to this question comes down to certain beliefs entrenched in the legal profession.

The first belief is in the uniformity of expertise: a judge is neither recognised as out of his depth nor is he recognised as an expert in the field. It is considered vital to the perception that justice has been done that each judge is seen to be the equal of every other. The expertise of the judge is seen to be the particular application of fairness, integrity and even-handedness with which they carry out their duties.

The second belief is in the interchangeable nature of expertise: every judge is able to learn and apply a new aspect of law as if he were an able decision maker in the field because he has demonstrated that ability with regard to other areas of law. The belief is that the judge clever enough to master equity can be equally adept at criminal procedure.

At a deeper level, there is the belief that judges have no personal characteristics relevant to the decision making process. Within the field of legal reasoning, judges are seen as impersonal and apolitical, rather than as individuals engaged in a process that integrates the application of their personal views, opinions and convictions with the letter of the law. In a post-modern age, how much longer can we sustain this ideal?