New on SSRN: Ariadne's Thread, a measurement-theoretic method for legal openness. Read the paper
Determinacy and Gray Areas

Legal openness

The degree to which the disposition of a legal question depends on who decides it rather than on the legal materials, measured as the instability of a ruling when the law is held fixed and only judicial posture varies.

First used in Ariadne's Thread

Legal openness is the construct that Posture Dispersion (Z) operationalizes. It turns the old dispute over legal determinacy into a measurement problem. Rather than assume, with Dworkin, that right answers exist, or with the strong indeterminacy thesis that they pervasively do not, the method measures how open each question is and lets the distribution speak.

The number is jurisprudentially ecumenical. A positivist reads high openness as a zone where the legal materials leave discretion to the judge; a Dworkinian may read it as a place where the instrument has not yet found the best interpretation. The number is the same; the gloss differs.

Openness is distinct from textual ambiguity, which is a property of words, and from outcome unpredictability, which mixes the openness of the law with the quality of features and training data.

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Used in

18 Jul 2026Ariadne's ThreadLegal Determinacy as Measured Dispersion across Posture-Instantiated AdjudicatorsRoss Brodskiy and Nathan Pokov · 8 min readPaperDeterminacy18 Jul 2026Before You FileWhat a Measured Openness Score Would Change About Budget, Settlement and Motion Strategy, and What to Ask Before You Trust OneTom Brennan · 7 min readField GuideDeterminacy18 Jul 2026From Hercules to AriadneHow a Half-Century Quarrel in Jurisprudence Became a Quantity, and What the Quantity Cannot SettleJulian Fenwick · 10 min readEssayMachine Jurisprudence18 Jul 2026Monday Morning with ZA review of Brodskiy and Pokov, Ariadne's ThreadMarcus Hale · 6 min readReviewDeterminacy18 Jul 2026Posture, Standard, and the Shape of DiscretionA review of Brodskiy and Pokov, Ariadne's ThreadEleanor Voss · 6 min readReviewDeterminacy18 Jul 2026The Thread in the CourtroomSome Cases Have One Path and Some Have Many. What Would It Mean to Measure the Difference?Elena Voss · 9 min readEssayDeterminacy18 Jul 2026Three Questions and One NumberA review of Brodskiy and Pokov, Ariadne's ThreadPriya Raman · 6 min readReviewDeterminacy18 Jul 2026Who Holds the Thread?A review of Brodskiy and Pokov, Ariadne's ThreadNora Kestrel · 6 min readReviewDeterminacy18 Jul 2026Z, FormallyInputs, Rules, Inference Procedure, Outputs: What Ariadne's Metric Measures and What Its Theorems ProveAda Mercer · 9 min readEssayDeterminacy21 Jun 2026From the Supreme Court Machine to Ariadne's ThreadRoss Brodskiy · 3 min readEssayDeterminacy