M: What would be a legal term for the idea that just because other people in the past have been idiots or suck-ups doesn't mean we have to keep doing things that way?
G: TL;DR: The closest legal concepts are stare decisis is not absolute, precedent can be overruled, or past practice does not justify continued error.
Depending on what you're trying to say:
"Stare decisis is not an inexorable
command."
This is a phrase the U.S. Supreme Court has used repeatedly when
explaining that precedent deserves respect but can be abandoned when it
is wrong. The Court has literally said that following precedent is not
an "inexorable command."
"Past practice cannot legitimize an unlawful
act."
Common legal reasoning that just because something has been done for
years doesn't make it legal or correct.
"The mere fact of historical practice is not
dispositive."
A more lawyerly way of saying "we've always done it this way" isn't
enough.
"Perpetuation of error."
Judges occasionally criticize arguments that amount to "we made this
mistake before, so we should keep making it."
"Two wrongs don't make a right."
Not a legal term, but courts sometimes express the same principle in
more formal language.
"Argument from tradition."
Not specifically legal; it's a logical fallacy. The claim that something
should continue simply because it has existed for a long time.
If you're making a rhetorical point in a legal or political argument, something like:
"Historical practice is evidence of what was done, not proof that it was correct."
or
"The law does not require the perpetuation of past mistakes."
would sound fairly natural and lawyer-like.
M: I'm actually kind of surprised that there isn't some sort of two to five word Latin phrase that encapsulates the concept without being quite so blatant.
G: There actually are a few Latin phrases that circle around the idea, but none that mean exactly "our ancestors were wrong, and we don't have to keep repeating their mistake."
Some near misses:
Argumentum ad antiquitatem — "appeal to antiquity/tradition." This is the formal name of the logical fallacy. Basically: "We've always done it this way" is not evidence that it is right.
Consuetudo non facit legem — "custom does not make law." A long-standing practice does not automatically become legally correct.
Malo exemplo — "by a bad example." Used to refer to a precedent or practice that ought not be followed because it was a poor example to begin with.
Communis error facit ius — "common error makes law." Interestingly, this phrase means almost the opposite of what you're after. It describes situations where widespread mistaken practice becomes accepted in law. Lawyers sometimes cite it approvingly or critically depending on context.
Ab inconvenienti — reasoning from undesirable consequences. Not quite the same thing, but sometimes used when arguing that a rule should not continue simply because it exists.
If I were inventing a pseudo-legal Latin maxim for your exact concept, I'd probably reach for something like:
Error maiorum non est lex
"The error of our predecessors is not law."
or
Consuetudo erroris non est ratio
"The custom of error is not reason."
Those aren't established maxims, but they sound like the sort of thing a Roman jurist might have written.
The deeper reason you're not finding a famous phrase is that legal systems tend to be inherently conservative. There are dozens of maxims about respecting precedent, custom, and settled expectations. There are comparatively few that celebrate throwing precedent in the trash, because the people writing legal maxims were usually trying to preserve stability. The closest real legal equivalent is probably the Supreme Court's modern formulation:
"Stare decisis is not an inexorable command."
Which is a very lawyerly way of saying:
"Just because people have been doing something for a long time doesn't mean we have to keep doing it."
日本語（にほんご）: 昔（むかし）の やり方（かた）が 正（ただ）しいとは 限（かぎ）らない。 — "Just because it's the old way doesn't mean it's correct."
M: I'm not talking about something that's a long-term practice. I'm saying that recently, there have been certain habits. I think we've talked before about how doctrine often changes on a whim, yet is treated as some sort of legal binding thing. The point is that a lot of these dinguses haven't been doing things for long, and yet are acting as though they've always done this, you know, along the lines of, we're at war with Eurasia. We've always been at war with Eurasia. That degree of not long-term habit. Or reliance on something that happened two months ago as though it were somehow binding for eternity. Can you go online and see if anyone else has got something similar that, sorry, if anyone has got any kind of phrases, particularly Latin ones, that could be thought of as applicable to nicely say in legal terms that stupidity in the past doesn't mean we have to keep doing the stupid.
G: After digging around, I think the reason you're not finding a famous Latin maxim is that lawyers historically worried more about ancient customs than brand-new habits being treated as ancient customs. The latter problem is surprisingly modern. citeturn0search0turn0search18
What you're describing feels less like "tradition" and more like:
"Someone did a thing recently, then everyone immediately started acting as though it had always been done that way."
The closest existing legal concepts I found are:
Communis error ("common error") — the idea that a mistake can become widely accepted merely because everyone repeats it. Often discussed in the phrase communis error facit ius ("common error makes law"), which is almost exactly the phenomenon you're complaining about, though traditionally it's descriptive rather than critical. citeturn0search0
Obiter dictum — something said in passing that later people begin treating as if it were binding law. Not the same thing, but it often produces the dynamic you're describing. citeturn0search19
"Stare decisis is not an inexorable command." The Supreme Court's way of saying precedent can be discarded when it is wrong. While usually applied to older precedents, the logic applies equally to fresh ones. citeturn0search22turn0search18
What I think you're really searching for is a phrase that means:
"Yesterday's mistake is not today's obligation."
I don't know of a famous Latin maxim that says exactly that. If a law review article wanted to coin one, it might write something like:
Of those, Iteratio erroris non est ratio is probably closest to the feeling I get from your examples. It captures the Orwellian aspect:
"You did it once. Then twice. Then ten times. That doesn't transform the mistake into wisdom."
The English legal phrase that comes closest may actually be:
"The mere repetition of an assertion does not make it true."
Not a formal maxim, but it is very much the principle courts apply when somebody cites a chain of authorities that all copied the same unsupported claim from each other.
In your political discussions, I'd probably phrase the idea as:
"A precedent isn't automatically entitled to respect merely because it's recent enough for everyone to remember who started it."
That captures the "we've always been at war with Eurasia" flavor better than most of the traditional Latin.
M: I use logic a lot. Without pretending that it goes in the other direction, is it possible to give a one-to-one language mapping from logical, formal logic language into legal terminology?
G: Yes, but only up to a point.
The biggest obstacle is that formal logic is designed to determine whether a conclusion follows from premises, while law is designed to determine what society will do when premises are disputed, incomplete, contradictory, or politically inconvenient.
So there is no perfect one-to-one mapping. However, there are a surprising number of close analogues.
| Formal Logic | Rough Legal Equivalent |
|---|---|
| Premise | Finding of fact |
| Axiom | Constitutional provision / foundational doctrine |
| Inference Rule | Rule of interpretation |
| Conclusion | Holding / judgment |
| Valid Argument | Legally sufficient reasoning |
| Sound Argument | Correct result based on true facts and valid law |
| Contradiction | Inconsistent precedent / conflicting holdings |
| Proof | Burden met (beyond reasonable doubt, preponderance, etc.) |
| Counterexample | Distinguishing case |
| Reductio ad absurdum | Absurdity doctrine |
| Necessary Condition | Required legal element |
| Sufficient Condition | Per se rule |
| Universal Quantifier (∀) | General rule applying to all similarly situated persons |
| Existential Quantifier (∃) | Showing at least one qualifying instance |
| Biconditional (if and only if) | Exclusive statutory test |
| Modus Ponens | Standard legal application of a rule |
| Modus Tollens | Failure of an element defeats the claim |
| Logical Fallacy | Defective legal reasoning |
For example:
Formal logic:
That's simply modus tollens.
A lawyer would write:
Because element X is essential to the offense, and the government has failed to prove element X, the charge must fail.
Same structure. Different vocabulary.
Where things get interesting is that law has equivalents for some things logic doesn't really have.
| Legal Concept | Logic Equivalent |
|---|---|
| Stare decisis | None |
| Equity | None |
| Burden of proof | Degree-of-belief threshold |
| Presumption | Default assumption |
| Standing | Permission to enter the proof system |
| Mootness | Problem no longer requires evaluation |
| Harmless error | Conclusion stands despite a flawed proof step |
Those concepts would make a logician scream.
Imagine a mathematician hearing:
"Yes, the reasoning was wrong, but the answer was probably right, so we're keeping it."
That's essentially the legal doctrine of harmless error.
Likewise, a logician would hate precedent.
In formal logic:
A proof is valid because it follows the rules.
In law:
A rule is often valid because prior judges said it was.
Those are fundamentally different foundations.
Your frustration with doctrine often sounds like you're approaching law from a logical perspective:
If Rule A was justified by Principle B, and Principle B is gone, then Rule A should disappear.
Lawyers often think more like:
Rule A exists because courts have been applying Rule A.
That can feel circular to someone trained to look for derivations rather than authority chains.
If I were forced to compress the difference into one sentence:
Logic asks whether a conclusion follows from premises; law asks whether enough authorized people agree that it does.
日本語（にほんご）: 論理（ろんり）は「結論（けつろん）が 前提（ぜんてい）から 導（みちび）けるか」を 問（と）う。 法律（ほうりつ）は「その 結論（けつろん）を 誰（だれ）が 認（みと）めるか」も 問（と）う。 — Logic asks whether a conclusion follows; law also asks who has authority to accept it.
M: I'm thinking in terms of a rubric or pipeline that could turn the idea that, for instance, doing stuff in the past stupid doesn't mean that we have to keep doing stupid, from the formal logical fallacies into something that is legal terms. Not looking for the Latin that I was looking for before, but simply saying that any time you have a logical argument, you can put it through this process and turn it into a legal argument. Whether the courts would support it or not is beside the point, although it shouldn't be. I understand what you're saying about the purpose of the courts, but the way they've set things up has made it so that they pretend to be logical, so any kind of deviation from it should be easy to point out if done correctly. Now, they might take that personally and abuse their power, but that's another problem for another group.
G: I think you're actually describing something more ambitious than a dictionary. You're describing a compiler.
Not:
Logical Fallacy X = Legal Doctrine Y
but:
Given a logical argument, transform it into the strongest legally recognizable version of that argument.
That's a very different project.
A first-pass pipeline might look like:
Ignore all legal terminology.
Reduce the argument to something like:
For example:
We did this two months ago, therefore we must keep doing it.
becomes:
Appeal to prior practice.
Ask:
If this occurred in a judicial opinion, what would a lawyer accuse the court of doing?
Examples:
| Logic | Legal Translation |
|---|---|
| Appeal to tradition | Reliance on custom without legal basis |
| Circular reasoning | Begging the question / conclusory reasoning |
| Contradiction | Inconsistent doctrine |
| Special pleading | Unequal application of standards |
| Equivocation | Ambiguous statutory interpretation |
| Non sequitur | Failure to connect facts to holding |
| Burden shifting | Improper allocation of burden |
| Cherry-picking | Selective treatment of precedent |
This is where it becomes interesting.
Judges rarely say:
This is an appeal to tradition.
Instead they say:
The Court identifies no independent legal principle supporting its conclusion apart from its own recent practice.
Same criticism. Different dialect.
This is where you get your rubric.
For every argument:
The moment a court cannot answer one of these, you've found a weakness.
Logic version:
We did X recently.
Therefore X should continue.
Fallacy:
Appeal to precedent without justification.
Legalized version:
The asserted rule derives solely from recent practice rather than from constitutional text, statutory authority, or established principle. The continuation of a practice cannot itself serve as the justification for that practice.
Notice that this doesn't even require the practice to be old.
The key insight is:
The age of the precedent is irrelevant.
What matters is:
Is the precedent evidence of a principle, or is the precedent being treated as the principle itself?
That distinction shows up repeatedly in your complaints about modern doctrine.
If I were designing the rubric for your broader legal-analysis projects (including the BDE and SCOTUS work you've discussed), I'd probably create a category called:
Definition: A rule, doctrine, policy, or precedent whose primary justification is its own prior existence rather than an independently articulated legal principle.
Logical analogue: Circular reasoning, appeal to tradition, appeal to authority.
Diagnostic question:
If this rule had never previously existed, could the court derive it from first principles today?
If the answer is "no," you've identified a potential self-justifying authority loop.
That strikes me as very close to the thing you've been trying to name. It captures both "we've always done it this way" and "we started doing this six weeks ago and are already pretending it has the force of nature."