If there's no known offence either in directly citable case law, or explicitly defined in legislature-ratified statute, then where can a judge gain the power to define a novel offence on which to condemn someone's conduct?

Before the tort of trover existed, ie before it was defined in common law by a judge, how could the first judged perpetrator have known that it was illegal before they did it?

I mean it seems like that is actually a lot more leeway than judges now have to introduce novel concepts as axioms into their common law canons. Nowadays judges don't have a power to "create law" other than in case of an ambiguity or lacuna if there's no such offence defined in statutes or precisely citable precedents. Why did judges in the past have the power to arbitrarily define new torts and coin/make up words to name them, but seemingly not judges today? What gave them the power to do so and then what took away that power? Doesn't that remove the principle of legal certainty?

  • What is the source of the quote here, please? Jul 8, 2022 at 15:34
  • A comment I wrote in another thread that was the inspiration for this question. Jul 8, 2022 at 16:07
  • then please link to it.. right-0clicking on the timestamp of a comment provides a link Jul 8, 2022 at 16:09
  • Okay I'll try to find it again. Jul 8, 2022 at 16:12

2 Answers 2


Judges never had the power to create law

When a judge refines a law, they are discovering a law that already existed in contemporary society. That is, someone has transgressed a social norm and caused injury to another, a suit or prosecution is brought and the judge “discovers” that the social norm has the force of law. This creates a precedent for other judges. If this is frequently used it becomes an established part of the common law. If it isn’t then the law falls into disuse.

Common law judges can still do this. The scope for “discovering” law is more narrow today than it was 500 years ago for several reasons:

  • Communication technology: pre 15th century judges didn’t have a printing press, pre 19th century judges didn’t have a railway, pre-20th century judges didn’t have photocopiers and pre-21st century judges didn’t have the internet. Each of these developments has meant that cases can more easily be fitted to known precedent.
  • More active legislatures: more and longer laws are passed each passing decade. More statute law means less common law.
  • more creative legal reasoning: it’s far more likely for a judge to expand an existing category than to create a new one.
  • On what basis do they discover that a given social norm either does or doesn't have the force of law? Jul 9, 2022 at 3:08
  • I mean doesn't this completely negate the distinction between uncouth and illegal? Since when is it illegal to violate social norms? If I'm not mistaken I'm legally entitled in the US to wear a swastika lapel around town but it would also certainly violate social norms and get me dirty looks. Jul 9, 2022 at 3:10
  • 1
    @JosephP. I don’t understand your question- there is no new law there, freedom of speech is a well established legal right with long standing precedent
    – Dale M
    Jul 9, 2022 at 3:34
  • Yes but before it was, the judge would have a chance to had "discovered" that this person's lapel was very offensive to people and his mother and father and pastor and teacher should have taught this young man on school that it's wrong to wear stuff that's offensive and thus define the tort (or even criminal common law offence) of "troller" or to "discover" that, despite being offensive to people, everyone has a right in the interests of justice and halting the slippery slope toward authoritarianism and restricting criticism of the powerful of "free speech" including when others don't like it. Jul 9, 2022 at 7:31
  • If according to the legal fiction of stare decisis the law precedes its discovery by judges, then how is it determined by judges? You have suggested that they do it simply by describing social norms. But that cannot be so because having free speech protections enshrined we have clear conflicts between behaviour that is legally protected and permitted, but socially sanctioned by norms. Jul 9, 2022 at 7:32

Judges don't now have the power to create law in the sense that you seem to be talking about, and I don't think they ever did, it's just that they relied on other authorities in the past.

"Substantial due process" is a legal doctrine that is law-like in that it refers to something that judges use to make rulings. The concept was created by the courts via the usual common-law rule "stare decisis" whereby announced rules are generally applied to analogous cases. This one is rooted in a specific text, the US Constitution, which refers to due process of law – that is the starter. Other ideas (a feeling of what constitutes justice for example) are mixed in, and we derive a specific rule which is used to guide the decision-making process.

The booklet An introduction to legal reasoning by Edwin Levi follows the historical development of the concept of "negligence" over a couple hundred years, with emphasis on how one court may "announce a rule" that refines a previously-existing rule, starting with Dixon v. Bell, referring to existing doctrines (dating back to Roman times, applied to dogs) about "dangerous objects".

In the past, one would learn of your social obligations in church, school, from your parents... same as today. A "reasonable man" would know that it is forbidden to steal, because everybody says so. Same with killing, maiming; also taking the money to do a job and then not doing the job. If you think that "I changed my mind, I don't want to do the work" is a good reason to not do the work and yet still keep the money – if you don't feel bound by your agreements, or if you don't understand the concept of "property" – they you may indeed be surprised when the court tells you that you are wrong, and forces you to compensate your victim.

  • What other authorities did the previously rely on? Jul 8, 2022 at 16:08
  • Well obviously in such a caricaturely clear cut scenario, yes. But in more complex ones morality is not so clear cut. For example many feel legally justified to shoplift from billionaires to feed their families and many great philosophers and even many parents teachers and clergymen would concur with them but probably not many courts. However I think this begins as a really great answer. 👍 Jul 8, 2022 at 16:11
  • Isn't it substantive due process, though? Jul 9, 2022 at 3:07

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