More Determinate and Less Settled

A computational test of principled positivism
David G. Kamper
University of California, Los Angeles · University of Chicago Law School
This site hosts the replication package: the ten notebooks, the shared engine, and the saved outputs behind every reported number. The manuscript is under review and is available from the author at davidgkamper@ucla.edu.
Archived on Zenodo: 10.5281/zenodo.24121883.

The question

Mitchell Berman's principled positivism holds that legal content is fixed by a weighted balance of legal principles, each contributing force in proportion to its weight and to how strongly the facts of a case activate it.

F = Σi wi · ai

A principle's weight is how much it counts in the legal system generally. Its activation is how strongly it bears on the case at hand. The theory says the weights are grounded in legal practice, but it does not say what practice is, or how a pattern of practice fixes a number. This project gives the account its first systematic computational test, implementing it faithfully, varying its parameters across ranges no thought experiment could canvass, and measuring the results against what the theory itself requires.

Two findings

The formal apparatus is sound

Given faithful weights, the weighted sum does what Berman says it does. Its sharpest result holds before any weight is tuned: where a Hartian validation rule contradicts itself, certifying both sides of a genuine conflict at once, the weighted sum returns a single verdict, because summing weighted forces yields one net force with one sign. It also tolerates rough weights, weighs magnitude rather than ranking by fixed priority, and leaves less law unsettled than a tiered Hartian hierarchy. Several of these properties hold as theorems rather than as artifacts of a particular run.

That soundness rests on an appeal to practice the theory leaves underspecified

Four mechanisms by which practice might confer weight all clear every requirement the theory imposes. Yet they ground the principles into three distinct weight structures, and those structures decide about a third of cases differently. Practice is not unitary, and which construal of it governs can change what the law is.

Principled positivism therefore does not resolve the indeterminacy it inherited from Hart and Dworkin. It relocates it, from how principles combine, which it handles well, to which practice grounds the weights, and to the prior question of how legal grounds themselves change.

The four requirements

Every mechanism and every aggregation rule is held to the same four requirements, each drawn from something Berman claims or commits to, and each scored seed by seed across thirty random seeds.

RequirementOperational testBasis
Well-definedAt least two principles carry weight above a small cutoff The theory's plurality of weighted principles
Noise-tolerantCritical uncertainty σ* ≥ 0.07 "Rough weights suffice," his answer to Perry
Magnitude-weighingOn a magnitude-only perturbation, the sum changes its verdict more than five times as often as a lexicographic rule Principles weigh; they do not rank
More law than HartA positive determinacy advantage over the hierarchical Hart baselineHis answer to the "too little law" worry

Weight gradation and correlation benefit are measured but are not requirements. Berman's account, unlike Dworkin's, permits principles to carry equal weight, so no pass-or-fail verdict may depend on them.

The four mechanisms

MechanismWeight is conferred byWhere the weights lean
UptakeHow often the bench invokes a principle Textual and structural, with the moral principles at zero
RelianceEmbedding in the holdings that go on relying on it Moral
StrategicJudges adapting to which arguments move their colleagues Structural
AppointmentBench turnover, read out through surviving holding-support Moral

Reliance and appointment correlate at +0.93, closely enough that the two are in effect one structure. Uptake opposes both, at −0.78 and −0.75. So the four dynamics realize three distinct structures, not four.

Three Harts, kept distinct

The argument runs three separate Hartian comparisons, and they are never conflated.

Results

Every figure below is computed on synthetic cases with independent activations, the conservative baseline, so each should be read as a floor. Correlation only improves the model's performance. The one exception is the margin over Hart, which reverses under category-correlated activations and is reported as such.

FindingValue
Determinacy, general86.2%
Determinacy, conflict cases79.2%
Validation rule contradicts itself on directly opposed cases100%
Weighted sum contradicts itself0%
Critical uncertainty σ*, mean0.090
σ* under category correlation0.069 → 0.156
Margin over the hierarchical Hart+0.272
Magnitude probe, sum against a lexical rule9.7×
Equal weights against a vote-count15.4%
Four mechanisms, different verdicts36.1%
Four mechanisms, opposite determinate verdicts27.2%
Static model results
Figure 1. The static model. Determinacy against the threshold, the tolerance for weight error, and the comparison against the Hartian baselines.
Four mechanisms, three structures
Figure 2. Practice is not unitary. Each column is one mechanism's emergent weight vector. Reliance and appointment converge; uptake opposes both.
Threshold sensitivity
Figure 3. The determinacy threshold is a modeling choice rather than a quantity the theory fixes. The curve is smooth and monotone, with no privileged value.
Global sensitivity analysis
Figure 4. Global sensitivity. Variance in the output apportioned among the threshold, weight dispersion, activation correlation, and sparsity.
Aggregation rules by class
Figure 5. Ten aggregation rules sorted by a magnitude-only probe. Cardinal rules score 0.023 to 0.075, every ordinal rule exactly 0.000, and the lexical foils 0.0024 and below. Ordinal aggregation is a coherent rival; only the lexical rules are the foil the theory is defined against.

The computational supplement

Ten notebooks, a shared engine, and the saved outputs behind every number above. All results were verified in Google Colab, run in dependency order, with each notebook carrying its own self-checks.

NotebookWhat it establishes
0Static properties: determinacy, noise tolerance, the Hart comparisons, the magnitude probe
1Uptake: weights emerging from a simulated bench, the live/dead cut, the cluster gap
2Reliance: weight from embedding in holdings
3Strategic adaptation, trained by REINFORCE
4The determinacy threshold swept from 0 to 0.30
5Ten aggregation rules across cardinal, ordinal, and lexical classes
6Sobol variance decomposition over four inputs
7The five theorems and the scope each is proved under
8Rebuilds every figure, table, and caption
9Appointment, and the decoupling test against reliance

Every notebook above is downloadable from this page, as is the saved output behind each number. To run them:

pip install -r requirements.txt

Notebooks 0 and 7 should be run before 8, which reads their summary JSON. The engine is computational/berman_core.py; it is duplicated inside notebooks/ so a Colab session can import it without a path fixup, and the two copies are byte-identical.

Citation

@software{kamper_berman_supplement_2026,
  author    = {Kamper, David G.},
  title     = {Computational supplement to "More Determinate and
               Less Settled"},
  year      = {2026},
  version   = {1.0.0},
  publisher = {Zenodo},
  doi       = {10.5281/zenodo.24121884}
}

@article{kamper2026determinate,
  author = {Kamper, David G.},
  title  = {More Determinate and Less Settled},
  year   = {2026},
  note   = {Manuscript}
}