Definition
Latin: "law not written." The body of law that derives its authority not from legislative enactment but from custom, long usage, and judicial recognition. In English and American legal tradition, lex non scripta is functionally synonymous with the common law — the accumulated body of judicial decisions, general customs, and particular local laws that govern conduct without having been reduced to a formal statute.
The term operates in deliberate contrast to lex scripta (written law), which encompasses statutes, codes, constitutions, and other formally enacted instruments. The distinction does not mean that common law is literally unrecorded or oral; centuries of reported decisions and treatises have committed it to writing. Rather, the term signals that common law rules derive force from recognition and usage rather than from a legislature's express command.
Common Confusion
The term is frequently understood as denoting law that is literally unwritten or oral — surviving only in memory and tradition. This was the root meaning, and some historical sources use the term that way. But the more precise legal sense, well established by Blackstone and carried forward through English and American jurisprudence, is narrower: lex non scripta designates law not enacted by a legislature, regardless of whether it has been written down. The common law fills volumes of reporters and treatises, yet it remains lex non scripta in the technical sense. Researchers encountering the phrase in historical sources should determine which sense the author intends before drawing conclusions.
Recognized Forms
/SUBTYPES
Historical usage recognized two principal components of lex non scripta:
General customs — rules of conduct observed uniformly throughout the realm and forming the core of the common law.
Particular customs — local or regional usages that deviated from the general rule in specific localities, trades, or communities, and which were legally binding in those limited spheres when sufficiently proven.
Particular local laws — statutory or quasi-statutory rules of limited geographic application, such as the customs of particular cities or boroughs, which occupied a middle ground between enacted law and pure custom.
Why It Matters in Research
Researchers encounter lex non scripta most often in foundational common law texts, constitutional arguments about judicial versus legislative authority, and debates over codification. Several navigational points matter:
The term is a period marker. Heavy use of lex non scripta (rather than "common law") signals English and early American legal writing, particularly pre-nineteenth century. When you see it in a source, you are almost certainly in a document engaging with the classical English legal tradition — Blackstone, Coke, or their American inheritors.
The codification debates amplify the term. Throughout the nineteenth century, reformers (Jeremy Bentham most forcefully, David Dudley Field in the United States) attacked lex non scripta as irrational and undemocratic. Opponents of codification defended it as the repository of organic legal wisdom. Encountering the term in this period often means you are inside that argument, and the author's use of the phrase may itself be polemical.
The term recedes but does not disappear. By the late nineteenth and twentieth centuries, "common law" displaced lex non scripta as the standard term in American practice. Finding lex non scripta in a relatively modern source usually means the author is engaging self-consciously with historical or comparative legal theory, or is writing in an academic register.
Jurisdictional and conflict-of-laws research. The lex scripta / lex non scripta distinction carried weight in early choice-of-law analysis, where courts and writers distinguished between applying enacted foreign statutes (lex scripta, more readily recognized) and extending the unwritten common law of another jurisdiction (lex non scripta, treated with more caution).
Historical Dictionary Support
The four source dictionaries are in close agreement on the core definition: lex non scripta is the unwritten or common law, comprising general customs, particular customs, and particular local laws. All four point toward Stephens' Commentaries (1 Steph. Com. 40–68) as the supporting authority, and several track language that originates in Blackstone's Commentaries, Book I.
Burrill's entry is the most analytically useful of the four. It correctly identifies the critical clarification — that the term is applied to common law "not in the literal sense of an unwritten or oral law, but in that of a law not derived from express legislation." This distinction between the literal and technical sense is precisely the point most likely to mislead modern researchers, and Burrill flags it explicitly where the other dictionaries do not. Burrill also notes the term's application to the Salic law, a useful reminder that lex non scripta was not used exclusively in the English common law context; civilian and continental writers applied it more broadly.
Black's, Rapalje & Lawrence, and Bouvier's all offer essentially identical three-element definitions (general customs, particular customs, particular local laws) without elaboration. They are reliable for identifying the term but do not help the researcher understand the conceptual stakes.
None of the four dictionaries engage seriously with the codification debates that defined the term's political valence in the nineteenth century — a significant gap for researchers working in that period.
Jurisdictional Note
The term originates in English law and is most at home in the common law tradition. Civil law jurisdictions use analogous concepts but not this terminology. In the United States, the distinction between lex scripta and lex non scripta appeared frequently in early constitutional debates and in arguments over whether federal courts possessed a general common law jurisdiction — a question ultimately answered in Erie Railroad Co. v. Tompkins (1938).
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Common Law — Origins and Development; Codification and Law Reform Movements; Lex Scripta.