Definition
Fungibiles res (Latin: "fungible things") is a civil law term designating a class of goods or commodities that are interchangeable by their nature — meaning one unit is the equivalent of any other unit of the same kind, quality, and quantity. Because individual items within the class are indistinguishable from one another, any one item can substitute for, or represent, another without loss of value or identity to the parties involved.
The concept is foundational to understanding how ownership, obligation, and risk transfer operate in transactions involving bulk or undifferentiated goods. A bushel of wheat, a gallon of oil, a sum of money, or a quantity of grain are classic examples: no particular bushel is unique; any bushel of the same grade satisfies an obligation calling for a bushel. By contrast, a specific named horse, a named painting, or an identified parcel of land is non-fungible — it cannot be substituted, because its particular identity is part of what is bargained for.
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Common Confusion
FUNGIBILES RES vs. FUNGIBLE THINGS (modern usage): The Latin form fungibiles res appears primarily in civil law treatises and early common law dictionaries. Modern American legal writing almost universally uses the English equivalent "fungible goods" or "fungible things." Researchers encountering fungibiles res in historical texts should treat it as the direct antecedent of the modern term. The underlying legal concept is unchanged; only the nomenclature has shifted. Do not confuse the Latin phrase with any procedural or evidentiary doctrine — it is a property and contract classification, not a rule of court.
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Why It Matters in Research
The Latin phrase is essentially a period marker. Its appearance in a source signals civil law influence — Roman law, Louisiana civil law, or early American treatise writing drawing on Continental sources. Researchers using the Law Mind corpus should expect to encounter fungibiles res in works on obligations, sale of goods, bailment, mutuum (the loan for consumption), and property classification, not in common law procedural texts.
Several research traps arise here:
First, the phrase does not appear consistently. Some sources use fungibiles res, others fungibles, others simply "things consumable by use" — all pointing at the same concept. A word search limited to the Latin form will miss substantial relevant material.
Second, the civil law treatment of fungibility is tighter and more categorical than modern common law or UCC usage. Under the civil law framework, fungibility is an objective property of the thing itself, determined by its nature. Under the modern UCC, fungibility can be contractually defined or contextually determined — a subtler and more flexible standard. Historical civil law sources will not capture this evolution.
Third, the classification matters practically in historical sources discussing mutuum (a loan of fungibles, where ownership transfers and an equivalent must be returned) versus commodatum (a loan of non-fungibles, where the specific item must be returned). Confusing the two distorts the analysis of early commercial and banking law.
For researchers tracing the concept into American law, the path runs through civilian-influenced treatises (Story, Pothier in translation, and Louisiana civil law materials) before arriving at the modern Uniform Commercial Code's treatment of fungible goods.
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Historical Dictionary Support
Both editions of Black's Law Dictionary agree on the core substance, though the second edition simply redirects to the English title "Fungible Things" rather than restating the definition — an editorial choice that signals the Latinism was already receding from active legal vocabulary by the early twentieth century.
The first edition's entry is the more instructive of the two. It quotes the operative Latin rationale directly: mutua vice funguntur — "they replace and represent each other" — which captures the essential logic of the classification more precisely than a plain English gloss alone would. The entry also draws on Sanders's edition of Justinian's Institutes, correctly grounding the concept in Roman civil law rather than common law sources.
What the historical dictionary entries do not address: the relationship between fungibility and risk of loss, the role of fungibility in distinguishing mutuum from commodatum, or the concept's migration into equity (tracing commingled fungible property in trust disputes). Researchers needing that material must look beyond the dictionary entries to treatise literature.
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Jurisdictional Note
The term and its underlying doctrine carry greatest weight in Louisiana, where the civil law tradition directly incorporates Roman classifications of things. In common law jurisdictions, the concept survives in modern statutory form under the Uniform Commercial Code's definition of fungible goods, but the Latin terminology is absent from American statutory and most modern case law.
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