Definition
A Latin maxim term meaning "like" or "similar." In legal usage, *similis* appears primarily as a component of the brocard *de similibus idem est judicium* — "as to like cases, the judgment is the same" — which expresses the foundational common law principle that analogous facts warrant analogous legal outcomes. The term itself is rarely used as a standalone legal noun or descriptor; its significance lies almost entirely in its role within this and related maxims of analogical reasoning.
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Common Confusion
*Similis* is sometimes loosely equated with *quasi*, and Anderson's entry explicitly directs the reader to compare the two. They are not synonyms. *Quasi* denotes something that resembles or approximates another legal category without fully being it — "as if" or "almost." *Similis* denotes straightforward likeness or similarity, used in the context of applying precedent or analogical rules to comparable fact patterns. A *quasi*-contract is not simply a similar contract; it is a legal construct that operates *as though* a contract existed. The distinction matters when researching how courts apply analogical reasoning versus how they invoke legal fictions.
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Why It Matters in Research
Researchers encountering *similis* in historical legal texts should treat it as a signal that the source is invoking analogical reasoning — the author is arguing that because the instant case resembles a prior case or established category, the same rule should apply. This is a common rhetorical and doctrinal move in pre-modern legal writing, where explicit statutory authority was scarce and maxims carried substantial authority.
The practical research trap is treating *de similibus idem est judicium* as a rule of decision rather than a principle of interpretive method. Historical courts and commentators cited it as persuasive framing, not as an independently operative legal standard. Modern researchers reading older equity or common law opinions should understand that invocations of *similis* or the *de similibus* brocard reflect the court's effort to justify extension of existing doctrine, not citation to a discrete legal rule.
In the Law Mind corpus, *similis* and the *de similibus* maxim will appear most frequently in: (1) treatises and digests organizing case law by analogy; (2) equity opinions justifying novel relief by comparison to established categories; and (3) collections of legal maxims used as secondary authority. Cross-referencing entries on *quasi*, analogy in legal reasoning, and the role of maxims in common law argument will yield the most productive results.
Jurisdictional variation is minimal for this term because it functions as a maxim of general reasoning rather than a term of art tied to a specific body of substantive law. Its force was recognized across English and American common law traditions.
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Historical Dictionary Support
Anderson's entry is minimal: it defines *similis* as "like," cross-references *quasi*, and reproduces the *de similibus idem est judicium* maxim without elaboration. This brevity is typical of how historical law dictionaries treated foundational Latin terms — the maxim was presumed to be known to the reader, and the entry functioned more as a locator than an explanation.
Historical dictionaries generally do not distinguish between *similis* as a term of art and *similis* as ordinary Latin. This is a gap researchers should note: the appearance of the word in a Latin text does not always signal legal-technical usage. Context — particularly whether it appears within a recognized brocard or maxim — determines whether the legal or merely descriptive sense is intended.
No significant divergence among historical sources on this term; the definition and associated maxim are consistent across the tradition.
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