Each concept is read twice: whether the approach carries it over, and whether the approach's own sources claim it. A concept that the approach claims but does not carry over is a shortfall. A concept that it neither claims nor carries over is an omission, which marks a gap in the field rather than a failure of the work.
Reasoning by Analogy
PartialShortfall · partially preservedDefinition (Edward H. Levi, An Introduction to Legal Reasoning, 1949)
This procedure decides a new case by comparison with already decided ones. The judge states which features of the earlier case are relevant and which are not, and that selection is generally where the reasoning happens.
Analysis
Retrieval does find similar past cases, which resembles analogy. However, the resemblance is generally computed as embedding similarity, and no step states which features of the earlier case are relevant. For example, two complaints about a delayed refund may retrieve each other based on wording alone, even when one depended on a missed deadline and the other on a billing error. In Levi's account, the selection of features is where the reasoning happens. Here, it is replaced by a score that no one can inspect.
Holding vs. Dicta
AbsentOmissionDefinition (Arthur L. Goodhart, 1930)
This distinction separates the part of a past decision that binds later cases (the holding) from the remarks made along the way (the dicta), which do not. Without a way to tell the two apart, a body of precedent cannot indicate which of its own decisions are actually binding.
Analysis
Stored cases are generally not annotated, and nothing indicates which part of a case binds later cases and which part was incidental to it. As a result, the repository cannot say which of its own contents actually govern.
Distinguishing and Overruling
AbsentOmissionDefinition (Common-law practice)
These two techniques let a later court revise the record. Distinguishing confines an earlier precedent to its own facts, and overruling sets it aside altogether. Both are done openly and with reasons stated, which keeps a body of case law open to revision.
Analysis
The repository only grows. No case is confined to its facts, revised, or overturned, so early judgments generally continue to govern indefinitely. There is no procedure by which a judgment that later looks wrong can be set aside.
Paradigm Cases and Maxims
PartialNot claimedDefinition (Albert R. Jonsen & Stephen Toulmin, The Abuse of Casuistry, 1988)
This way of reasoning bases judgment on paradigm cases (i.e., clear cases on which agreement is easy) and on the short maxims drawn from them. A hard case is then settled by asking how far it is from the paradigms, rather than by deduction from a general principle.
Analysis
The repository is built from concrete cases, which is the raw material casuistry requires. However, no maxims are extracted and no case is marked as a paradigm, so a clear central case and a marginal one generally carry the same weight at retrieval time.