ARGUMENTUM - The Law Mind Legal Dictionary

ARGUMENTUMAuthored

The Law Mind • 1008 words

Definition

Latin. Literally, "that which makes clear or proves." In legal usage, argumentum means argument, reasoning, or inference — particularly of the presumptive or inferential kind. The term appears almost exclusively in Latin maxims and phrases embedded in legal opinions, treatises, and briefs, each encoding a principle about the weight or character of a particular mode of legal reasoning.

The most frequently encountered phrases include:

(1) Argumentum ab authoritate est fortissimum in lege — "An argument from authority is the strongest in the law." Reflects the traditional common law deference to precedent and established legal opinion.

(2) Argumentum a simile valet in lege — "An argument from analogy is valid in law." The foundation for analogical reasoning from like cases, central to common law method.

(3) Argumentum a divisione est fortissimum in jure — "An argument from division is the most forcible in law." Used to demonstrate that a thing cannot be what it is claimed to be if it possesses none of the necessary constituent parts.

(4) Argumentum a communi accidente in jure frequens est — "An argument based on common occurrences is frequent in law." Acknowledges that courts regularly reason from what ordinarily happens.

In its broadest classical legal sense, argumentum also carried the meaning of evidence, presumption, or inferential proof — not merely oral or written advocacy. This secondary sense appears in civil law sources and influenced how the term was used in treatise literature.

Common Language

Modern common usage (Wiktionary): Used in numerous Latin phrases, occasionally alone, in the sense of "appeal" or "argument."

Historical common usage (Webster's 1913): Not separately defined; treated as part of the Latin vocabulary of logic and rhetoric, meaning a proof or demonstration, or the subject matter of a discourse.

Editorial note: The gap matters for corpus research. In ordinary English, "argument" means a dispute or a line of reasoning offered in advocacy. In legal Latin, argumentum carries a third meaning — presumptive inference or evidence — that is closer to "proof" than to "argument" in the modern sense. A researcher encountering argumentum in a civil law or treatise context should not assume the term refers only to advocacy.

Common Confusion

Argumentum is sometimes read as a synonym for dictum when judges invoke Latin phrases in opinions. The two are distinct. Dictum is an incidental judicial statement not necessary to the holding; an argumentum phrase cited by a judge is a maxim about the nature of legal reasoning itself, invoked to justify or characterize the method of argument being used. Anderson's Dictionary of Law notes that arguendo — a related but different term — refers to an observation made in reasoning through an opinion that is incidental to the point at issue and therefore not authoritative. Argumentum and arguendo share a Latin root but function differently: argumentum names the type or mode of argument; arguendo flags that something is said hypothetically or in the course of reasoning rather than as a holding.

Why It Matters in Research

Argumentum entries are primarily encountered in three research contexts: (1) Latin maxim research, where the phrase itself carries substantive legal weight; (2) civil law and Roman law sources, where argumentum meaning "presumptive inference" or "evidence" appears in technical discussion of proof; and (3) judicial opinions and briefs citing maxims to legitimize a mode of reasoning.

Researchers in the Law Mind corpus should be alert to the following:

Phrase variation. The same underlying maxim sometimes appears with minor textual differences across treatises and reporters — communi accidente vs. communitur accidentibus, for example. Historical dictionaries do not always reconcile these variants, and the difference occasionally reflects different manuscript traditions rather than different legal propositions.

Civil law vs. common law weight. In common law sources, argumentum phrases are invoked as persuasive authority — rhetorical touchstones rather than binding rules. In civil law and Romanist treatise literature (the Digest citations in Burrill reflect this tradition), argumentum in the sense of inferential proof carries closer to evidentiary weight. The same phrase in a Civilian treatise and a common law opinion may be doing very different work.

Historical source gaps. The historical dictionaries cover the major Latin maxims but do not exhaustively catalog all argumentum phrases. Specialized collections of Latin legal maxims — Broom's Legal Maxims is the standard reference — will surface variants the dictionaries omit.

The arguendo connection. Searches on argumentum may surface arguendo hits and vice versa. Filter carefully; the two terms appear in different analytical registers.

Historical Dictionary Support

The three source dictionaries approach argumentum from complementary angles, together giving a fuller picture than any one provides alone.

Burrill offers the most substantive treatment, reaching back to civilian sources (Struvius, Matthaeus de Criminibus, Calvin's Lexicon Juridicum) to establish that argumentum in Roman law carried the senses of inference, deduction, presumption, and presumptive evidence — not merely argument in the advocacy sense. Burrill's citation to the Digest (48.18 and 49.16) anchors this reading in primary Roman law authority.

Rapalje & Lawrence catalog the major maxims with English translations, providing the practical phrase-by-phrase reference most useful for common law researchers. Their entry is efficient but does not engage with the civilian meaning.

Anderson's Dictionary of Law is the most etymologically minded, tracing arguere ("to argue") and noting the literal meaning — "that which makes clear or proves" — which helpfully bridges the advocacy and evidentiary senses. Anderson also provides the clearest treatment of arguendo as a distinct term, which aids in keeping the two separate.

All three dictionaries agree that the term is primarily a vehicle for the Latin maxims rather than a standalone legal concept. None of the three addresses the textual variant problem or the divergence between civilian and common law uses in any depth.

Encyclopedia Cross-Reference

See Law Mind Encyclopedia: Legal Maxims; Presumptions; Analogical Reasoning in Law.

ARGUMENTUMmain

Rapalje & Lawrence • 1888

- An argument (q. v.) Used in some Latin phrases, such asArgumentum a communitur accidentibus in jure frequens est: An argument based on common occurrences is frequent in law. Argumentum a divisione est fortissimum in jure: An argument from division is most forcible in law. To show that a thing is not what it is asserted to be, it is enough to prove that it does not contain any of the parts or divisions into which such other thing is divisible. Argumentum a majori ad minus negative non valet; valet e converso: An argument from the greater to the less is not forcible negatively; conversely, it is forcible. Argumentum a similis valet in lege: An argument from analogy is strong in law. Argumentum ab auctoritate 'est fortissimum in lege: An argument from authority is strongest in law. Argumentum ab impossibili valet in lege: An argument deduced from an impossibility is forcible in law. Argumentum ab inconvenienti plurimum valet in lege: An argument deduced from inconvenience (or hardship) is of the greatest weight in law. A construction of a writing which will plainly work great inconvenience will not be made, but another construction will be adopted, the first one not being considered within the intention of the writer. So where a law is uncertain, that construction will be adopted which is attended with the least inconvenience. ARIBANNUM.-A fine formerly imposed upon one who failed to set out to join the army after notice from the king so to do.

ARGUMENTUMmain

Burrill's Law Dictionary • 1867

Lat. Argument or reasoning; especially that of the presumptive kind. Struvius, Jurispr. Rom. Germ. lib. 4, tit. 11, n. 3. Inference or deduction; presumption. Matthæus de Crim. in lib. 48, Dig. tit. 15, c. 6. Evidence; presumptive evidence. Calv. Lex. Dig. 48.18. 1. 1, 4. Id. 49. 16. 5. 6. Argumentum ab authoritate est fortissimum in lege. An argument from authority is the strongest in the law. Co. Litt. 254 a. "The book cases are the best proof of what the law is." Id. ibid. Argumentum ab impossibili valet in lege. An argument drawn from an impossibility is forcible in law. Co. Litt. 92 a. Argumentum ab inconvenienti plurimum valet [est validum] in lege. An argument drawn from inconvenience is of the greatest weight [is forcible] in law. Co. Litt. 66 a, 97 a, 152 b, 258 b. Broom's Max. 84, [139.] If there be in any deed or instrument equivocal expressions, and great inconvenience must necessarily follow from one construction, it is strong to show that such construction is not according to the true intention of the grantor; but where there is no equivocal expression in the instrument, and the words used admit only of one meaning, arguments of inconvenience prove only want of foresight in the grantor. 3 Madd. 540. 7 Taunt. 496. 3 Bing. 590. So, where the law is doubtful and not clear, the judges ought to interpret the law to be as is most consonant to equity and least inconvenient. But where the law is known and clear, though it be inequitable and inconvenient, the judges must determine as the law is. Vaugh. 37, 38. And see per Bayley, J. 4 M. & S. 531. Sir W. Scott, 1 Dods. 402. Lord Brougham, 6 Cl. & Fin. 671. Argumentum a divisione est fortissimum in jure. An argument from division is of the greatest force in law. Co. Litt. 213 b. 6 Co. 60. Wingate's Max. 260, max. 71. Thus, to show that a certain annual payment of money is not properly a rent, Littleton argues from a division of the subject, thus: For if it should be a rent, it must be rent service, rent charge, or a rent secke, and it is not any of these." Litt. sect. 345. Lord Coke applies the same kind of argument to commons. 6 Co. 60. Argumentum a majori ad minus negative Argumentum a simili valet in lege. An argument from a like case, (from analogy) is good in law. Co. Litt. 191. ARIBANNUM, Arribannum. L. Lat. In old European law. A fine for not joining the army, when called out by public summons. Spelman. The summons or proclamation itself. Id. Spelman thinks the proper form of this word was heribannum, unless it be considered a contraction of arrieribannum, (q. v.) See Herebannum.

ARGUMENTUMmain

Anderson's Dictionary of Law • 1890

L. Argument: literally, that which makes clear or proves. Arguere, to argue. Arguendo. In reasoning, arguing. Abbreviated arg. Applied to an observation made by a judge in rendering an opinion, incidental to the point under discussion and, therefore, not authoritative. Argumentum a simile. Argument from a like case-from analogy. Argumentum a simile valet in lege. An argument from an analogous case has weight in law. See SIMILIS. Argumentum ab inconvenienti. Argument from a hardship, q. v. Nullum simile est idem. No like thing is the same; likeness or similarity is not identity. Thus, while a partner is like a joint-tenant and a tenant in common, he is neither; ¹ a telegraph company is like, but is not the same as, a common carrier; 2 an award of arbitrators is not like a judgment in all respects; a check resembles a bill of exchange, yet it is not the same thing. In the patent and copyright laws, identity, not resemblance, is regarded. Similiter. Likewise; the like. A reply that as one party has put himself upon the country, the other does the same. The full sentence was et prædictus similiter, equivalent to "and he does the like." Expresses concurrence in referring a trial to the jury. In strictness, no part of the pleadings: it neither affirms nor denies any fact; is matter of form. Spoken of as the similiter.5

argumentumnoun

Wiktionary (English) • 2026

Wiktionary contributors • CC BY-SA 4.0 • via Kaikki
Extracted and formatted for display by Law Mind. Source link opens the current Wiktionary page and its contributor history; it is not a frozen copy of this extract.

Used in numerous Latin phrases (and occasionally alone) in the sense of “appeal” or “argument”.

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