Definition
A Latin term from the civil and common law meaning "an instant" — the present moment in time, conceived not as a duration but as a point: the indivisible boundary between one period and the next. In legal reasoning, instans carries formal significance beyond its apparent simplicity. It names the theoretical moment at which one legal state ends and another begins — the conceptual hinge on which questions of simultaneity, succession, and vesting turn.
The governing maxim is: Instans est finis unius temporis et principium alterius — an instant is the end of one period of time and the beginning of another. This formulation, drawn from Coke on Littleton, captures the term's core function: instans is not a slice of time with measurable length, but a point of legal transition.
Common Confusion
INSTANS is sometimes encountered as a near-synonym for "instant" in older legal texts, and the two are easily conflated. The English word "instant" in historical legal usage (as in "the instant case" or "the instant in which an act takes effect") derives from the same Latin root and shares the same conceptual core. However, instans as a formal Latin term appears specifically in doctrinal arguments about the legal moment of transition — vesting, death, merger, relation back — where the question is not merely "now" but "at precisely which conceptual point does one legal condition end and another begin." The English "instant" in modern usage has largely shed this philosophical precision.
Why It Matters in Research
Researchers will encounter instans primarily in two contexts: first, in older common law treatises and commentaries where Latin maxims are invoked to resolve problems of simultaneity — most classically, whether two events can be deemed to occur "at the same instant" for purposes of inheritance, vesting of title, or the effect of a condition; second, in civil law sources where the term carries equivalent doctrinal weight.
The maxim attached to instans — that it is simultaneously the end of one period and the beginning of another — was not rhetorical decoration. Courts and commentators used it to reason through hard cases: if a grantor and grantee were deemed to hold title at the same instans, which interest governed? If two persons died simultaneously, at what instans did each estate vest? The term thus connects to the doctrine of commorientes (simultaneous death), to the law of remainders and vesting, and to questions of relation back.
The chief trap for researchers in historical sources is treating instans as merely a Latin flourish for "moment" or "now." When Burrill cross-references "See Instant," he is pointing to the English doctrinal usage — but the Latin form instans signals a more precise, philosophically loaded argument is being made, typically in a Coke-derived or civilian-influenced text. The presence of the term is often a marker that the author is invoking scholastic or Roman law reasoning about the indivisibility of time.
Modern legal research tools rarely index instans as a standalone concept; researchers should search the maxim directly (instans est finis unius temporis) or trace through the Coke on Littleton apparatus, particularly the commentary surrounding questions of seisin, entry, and the moment of legal effect.
Historical Dictionary Support
Burrill's entry is characteristically economical: a one-line definition, the governing maxim, a citation to Coke on Littleton at folio 185, and a cross-reference to the English form. This is sufficient to locate the term's doctrinal home but gives no guidance on the range of problems to which the concept was applied.
Burrill does not attempt a philosophical elaboration, nor does he canvas the civil law sources. Researchers working in civilian or mixed-jurisdiction materials should not rely on Burrill alone; the concept of the legal instant has a more developed treatment in Roman law commentary and in the continental natural law tradition, where questions about the simultaneity of legal acts received sustained attention.
No other source dictionaries in the current corpus carry entries for instans. The term is not common enough in modern legal writing to appear in contemporary dictionaries, which makes Burrill's cross-reference to the maxim and to Coke the primary access point for English-language legal research.