Definition
A Latin maxim meaning "by consequence" or "consequently." In legal usage, *per consequens* signals that a conclusion, right, obligation, or liability follows as a logical or legal inference from an established fact, prior ruling, or legal principle — rather than being stated expressly. It is a term of legal reasoning rather than a term of art with a defined substantive content of its own. When a court or pleader invokes *per consequens*, the argument is that the result being urged is not merely asserted but compelled by what has already been determined or admitted.
The phrase appears most frequently in older common law pleading and judicial reasoning, where chains of logical deduction governed both argument and judgment. It is less a rule than a marker — indicating the step from premise to conclusion in a legal syllogism.
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Common Confusion
*Per consequens* is sometimes loosely conflated with *ex consequenti* (from the consequence) or treated as interchangeable with *a fortiori* (with even stronger reason). These are related but distinct moves in legal argument. *A fortiori* signals that a conclusion follows with greater force from the premise; *per consequens* signals only that the conclusion follows as a matter of logical or legal necessity. Researchers working in Year Book materials or early common law reports should not assume these phrases are synonymous.
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Why It Matters in Research
*Per consequens* is primarily a phrase of legal method, not substantive doctrine, which means researchers will encounter it in argument and judicial reasoning rather than in statutory or doctrinal headings. Its importance is navigational: when you see *per consequens* in a historical source, you are watching a court or advocate work through a chain of legal inference — establishing that a particular consequence is legally compelled, not merely convenient.
The phrase appears in Year Book materials (the earliest citation in the source dictionaries is Yearb. M. 9 Edw. III), placing its practical use squarely in the medieval common law period. Researchers working in pre-modern English law will encounter it regularly in pleading records, abridgments, and early treatises. By the time of Blackstone and the later common law tradition, the explicit invocation of Latin maxims like *per consequens* recedes in favor of English phrasing, but the underlying logical structure — that consequence A flows necessarily from premise B — persists throughout legal reasoning to the present day.
For researchers using the Law Mind corpus, the significance of *per consequens* extends forward in time through its doctrinal descendants. Modern "per se" rules in tort and constitutional law are functional successors to consequence-based reasoning: once a predicate is established (violation of a statute, a physical taking), certain legal conclusions follow automatically — *per consequens*. Researchers tracing the intellectual genealogy of per se liability or automatic legal consequences will find the older Latin reasoning tradition a useful backdrop.
The Burrill entry contains an apparent transcription anomaly — the phrase "By the lawful judgment of his peers. Mag. Cart. 9 Hen. III. c. 29" appears appended to the *per consequens* entry, which is the definition of *per pares* or *per legale judicium parium* from Magna Carta. Researchers consulting Burrill directly should be alert to this editorial irregularity.
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Historical Dictionary Support
All three source dictionaries agree on the core translation — "by consequence; consequently" — and the earliest citation traces to Yearb. M. 9 Edw. III. Neither Black's first nor second edition elaborates beyond the translation and citation; this brevity reflects the phrase's status as a term of reasoning rather than a term with independent substantive content requiring extended definition.
Burrill's entry is anomalous. Following the standard definition and citation, it appends language from Magna Carta (9 Hen. III, c. 29) relating to judgment by peers — which belongs to an entirely different term. This appears to be a printing or compilation error in the source. Researchers should not treat the Magna Carta language as part of the definition of *per consequens*.
None of the historical dictionaries address the phrase's role within the broader structure of common law argument or its relationship to later per se doctrine. That connection must be drawn analytically, not from the dictionary record.
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Encyclopedia Cross-Reference
The logical structure underlying *per consequens* — that certain legal consequences follow automatically from established predicates — animates several modern doctrines discussed in the Law Mind Encyclopedia:
The Law Mind Torts & Personal Injury Encyclopedia: Negligence Per Se (Violation of Statute as Negligence) (torts_8)
The Law Mind Constitutional Law Encyclopedia: The Takings Clause — Physical Takings and Per Se Rules (constitutional_66)
The Law Mind Torts & Personal Injury Encyclopedia: Defamation Per Se Categories (torts_123)
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