Definition
Duration of life refers to the span of time a person is presumed or legally determined to be alive. In legal contexts, the term appears primarily in two connected settings:
1. Presumption of life. The law presumes a living person continues to live until evidence establishes otherwise. This presumption, however, is rebuttable and carries modest weight in most common law jurisdictions.
2. Presumption of death after absence. When a person has been absent and unheard from for a legally defined period — historically seven years in English and American common law — the presumption of continued life yields to a presumption of death. At that point, courts and legal instruments (wills, trusts, insurance contracts) may treat the person as legally dead for purposes such as inheritance, property transfer, or termination of marriage.
The phrase also appears in instruments creating life estates, annuities, and life insurance arrangements, where the duration of a person's life defines the operative period of a legal right or obligation.
Common Language
Modern common usage (Wiktionary): The length of time that a living being remains alive; the period from birth to death.
Historical common usage (Webster's 1913): "The time during which anything exists." Applied to persons, the natural life span from birth to death.
The common meaning and legal meaning largely converge on the bare idea of a life span, but the legal usage carries significant technical freight: duration of life in legal instruments is not simply a biographical fact but a legally constructed status. A person may be presumed dead — and their duration of life legally fixed — while they are still biologically alive, or presumed alive when the biological fact is unknown. The law does not merely observe the duration of life; it constructs it for defined legal purposes.
Why It Matters in Research
Researchers encounter this term most often in three overlapping areas of the Law Mind corpus: property law (life estates and future interests), probate and succession (death presumptions affecting inheritance), and insurance law (life insurance proceeds and beneficiary claims).
The seven-year absence rule is the central trap in historical sources. Earlier American cases applied the presumption inconsistently — some courts treated the seven-year period as establishing a presumption of death that shifted the burden of proof; others treated it as merely permissive evidence for the jury. Rapalje & Lawrence reflects the English rule that the presumption was "very slight" and readily rebutted, but American jurisdictions diverged on this point, and state statutes progressively codified and modified the common law rule. Researchers using pre-twentieth-century sources must check whether the jurisdiction treated the presumption as mandatory or merely evidentiary.
The Rapalje & Lawrence entry as it appears in the source material is fragmentary: it begins a substantive discussion of the presumption of continued life, then breaks into cross-references for an unrelated term (DURESS). This is a transcription artifact. Researchers should not treat the surviving text as a complete statement of the dictionary's entry on this subject.
In instruments, the phrase "for and during the natural life of X" or equivalent formulations creates a life estate or annuity measured by a life in being. Duration of life in this context connects directly to rules against perpetuities analysis, where lives in being anchor the perpetuities period.
For tax research, life insurance proceeds and the tax treatment of annuities depend on actuarial determinations of expected duration of life. The Law Mind Tax Encyclopedia entry on life insurance proceeds is relevant when researching the intersection of legal death presumptions and income exclusions.
Historical Dictionary Support
Rapalje & Lawrence is the sole historical dictionary source available for this entry, and the surviving text is incomplete as noted above. What the entry does establish is that English law placed relatively little weight on the presumption of continued life and that seven years' unheard absence was the operative threshold for rebuttal — consistent with the Statute of Frauds-era English rule and its American common law inheritance.
The surviving text does not address life estates, annuities, or insurance — major legal contexts where duration of life operates as a term of art. Researchers should not treat Rapalje & Lawrence as comprehensive on this subject. Older American treatises on real property (such as Kent's Commentaries) and on evidence (such as Greenleaf on Evidence) provide more complete treatments of the death presumption and its evidentiary status.
Jurisdictional Note
American states diverged significantly from the English common law baseline. Many states enacted statutes codifying the seven-year absence presumption, and some modified the period or created procedural mechanisms for a formal judicial declaration of death. These statutory schemes govern modern research; the common law presumption has largely been displaced in domestic contexts, though it may remain operative in cases falling outside statutory coverage.
Encyclopedia Cross-Reference
The Law Mind Tax Encyclopedia: Exclusions — Life Insurance Proceeds (tax_65) — relevant when duration of life intersects with insurance proceeds and income exclusion analysis.
The Law Mind Contracts & Commercial Law Encyclopedia: Contracts — Offer (Definition, Requirements, and Duration) (contracts_3) — tangential; relevant only when a contractual offer is measured by or conditioned on a party's life.