Penumbra (law)

Umbra, penumbra, and antumbra formed through windows and shutters. Jurists have used the term "penumbra" as a metaphor for rights implied in the constitution.^[1]

In United States constitutional law, the penumbra includes a group of rights derived, by implication, from other rights explicitly protected in the Bill of Rights.^[2] These rights have been identified through a process of "reasoning-by-interpolation", where specific principles are recognized from "general idea[s]" that are explicitly expressed in other constitutional provisions.^[3] Although researchers have traced the origin of the term to the nineteenth century, the term first gained significant popular attention in 1965, when Justice William O. Douglas's majority opinion in Griswold v. Connecticut identified a right to privacy in the penumbra of the constitution.^[4]

^ Burr Henly, "Penumbra": The Roots of a Legal Metaphor, 15 Hastings Const. L. Q. 81, 83–84 (1987) (discussing origin of term from its original scientific meaning); Glenn H. Reynolds, Penumbral Reasoning on the Right, 140 U. Pa. L. Rev. 1333, 1336 (1992) (discussing how the Supreme Court has found "a right of privacy implicit in the logic and structure of the Bill of Rights").
^ Merriam-Webster, Dictionary, Penumbra: Definition; see also Brannon P. Denning & Glenn Harlan Reynolds, Comfortably Penumbral, 77 B.U. L. Rev. 1089, 1092 (1997) (discussing definition of "Penumbral Reasoning").
^ Glenn H. Reynolds, Penumbral Reasoning on the Right, 140 U. Pa. L. Rev. 1333, 1334–36 (1992); see also J. Christopher Rideout, Penumbral Thinking Revisited: Metaphor in Legal Argumentation, 7 J. ALWD 155, 155–56 (2010).
^ See Griswold v. Connecticut, 381 U.S. 479, 484 (1965) ; Burr Henly, "Penumbra": The Roots of a Legal Metaphor, 15 Hastings Const. L. Q. 81, 83–84 (1987) (discussing origins of the term).

[1] Burr Henly, "Penumbra": The Roots of a Legal Metaphor, 15 Hastings Const. L. Q. 81, 83–84 (1987) (discussing origin of term from its original scientific meaning); Glenn H. Reynolds, Penumbral Reasoning on the Right, 140 U. Pa. L. Rev. 1333, 1336 (1992) (discussing how the Supreme Court has found "a right of privacy implicit in the logic and structure of the Bill of Rights").

[2] Merriam-Webster, Dictionary, Penumbra: Definition; see also Brannon P. Denning & Glenn Harlan Reynolds, Comfortably Penumbral, 77 B.U. L. Rev. 1089, 1092 (1997) (discussing definition of "Penumbral Reasoning").

[3] Glenn H. Reynolds, Penumbral Reasoning on the Right, 140 U. Pa. L. Rev. 1333, 1334–36 (1992); see also J. Christopher Rideout, Penumbral Thinking Revisited: Metaphor in Legal Argumentation, 7 J. ALWD 155, 155–56 (2010).

[4] See Griswold v. Connecticut, 381 U.S. 479, 484 (1965) ; Burr Henly, "Penumbra": The Roots of a Legal Metaphor, 15 Hastings Const. L. Q. 81, 83–84 (1987) (discussing origins of the term).

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