Adjacency Pair

one_liner: A typed first move that conditions a second and makes its absence noticeable.

core_idea:
An adjacency pair is a two-slot interactive unit in which an *initiating
move* (slot one) projects, conditions, and constrains a *paired response
move* (slot two) of a typed form-class, such that three things hold:
the absence of a slot-two *itself becomes a noticeable event* with social
or operational consequences; some response types are *preferred* and
others *dispreferred*, the dispreferred carrying added work in delay,
hedge, or account; and a mismatched or absent slot-two invites *repair*,
a request for re-attempt. The structural commitment is *sequential typed
conditioning with noticeable absence*: not merely a turn followed by a
turn, but a first-pair-part that specifies what properly belongs in the
second-pair-part slot and makes the gap visible when nothing fits.

The construct is associated with conversation analysis but its structural
shape recurs far beyond conversation. What travels is not the
conversational vocabulary but four commitments: *type-conditioning*
(slot one constrains slot two's form-class), *noticeable absence* (a
missing slot-two is data), *preference asymmetry* (asymmetric cost
between two valid slot-twos), and *repair affordance* (a discipline for
handling mismatch). When all four are present — in a network protocol, a
liturgy, a legal procedure, or a birdsong duet — the same structural unit
is operating, regardless of medium.

The pattern's power is that it makes silence a typed event rather than a
null state. A gap after a first-pair-part is not the absence of an
interaction; it is a specific, detectable outcome that the system must
either tolerate or notice, and that the participants read as meaningful.
That single reframing — absence as a positioned event within a typed
slot — is what unifies a timeout, a ritual breakdown, a procedural
default, and a conversational silence under one structure.

structural_signature:
*the first-pair-part (the initiating move)* — *the type-conditioning that projects a form-class for the second slot* — *the second-pair-part slot* — *the noticeable-absence of a fitting slot-two* — *the preference asymmetry between valid responses* — *the repair affordance for mismatch*

The pattern is present whenever these components are configured together:

- **The first-pair-part (role).** An initiating move that opens a
  two-slot unit and projects what properly belongs in the second slot.
- **The type-conditioning (relation).** The first move constrains the
  second slot to a typed form-class, so what counts as a valid slot-two is
  determined by slot-one's type, not by arbitrary succession.
- **The second-pair-part slot (role).** The projected response position,
  filled or unfilled.
- **The noticeable absence (invariant).** A missing slot-two is itself a
  positioned event with consequences — silence becomes a typed event
  rather than a null state, which must be either tolerated or noticed.
- **The preference asymmetry (relation).** Two valid slot-twos can be
  structurally unequal in cost — the dispreferred one carrying added work
  in delay, hedge, or account.
- **The repair affordance (relation).** A discipline for handling a
  mismatched or absent slot-two — a request for re-attempt — is part of
  the structure, not an emergency add-on.

The four commitments — type-conditioning, noticeable absence, preference
asymmetry, repair affordance — compose the signature, and pairs compose
further into chains analysable locally while coherent globally: a typed
first move that conditions a second and makes its absence a detectable
event.

what_it_is_not:
- **Not `compatibility`.** Compatibility is a static fit relation between
  two things; an adjacency pair is a *sequential* unit in which a first
  move *projects and conditions* a typed second, and makes the second's
  *absence* a noticeable event — a temporal, slot-filling structure, not a
  matching one.
- **Not `two_sided_matching`.** Matching pairs agents by mutual
  preference across a population; an adjacency pair is a two-slot
  interactive sequence within a single exchange, with a projected
  form-class and a repair affordance, not a stable-pairing problem.
- **Not `reciprocity`.** Reciprocity is the norm of returning like for
  like over time; the adjacency pair is the finer structural unit — a
  typed first-pair-part conditioning a typed second-pair-part — and its
  preference asymmetry is not a moral return but a cost difference between
  valid responses.
- **Not `turn_taking` alone.** Turn-taking is the bare alternation of
  speakers; the adjacency pair adds type-conditioning, noticeable absence,
  preference asymmetry, and repair — structure that mere alternation lacks.
- **Not `coordination` in general.** Coordination is any alignment of
  action; the adjacency pair is one specific mechanism — a typed first
  move whose absent second is a positioned event — by which local
  coordination is achieved.
- **Not `feedback`.** Feedback routes a measured output back to modify
  input; the adjacency pair's second-pair-part is a *typed projected
  response*, not a sensed quantity fed back to a setpoint.
- **Common misclassification.** Assuming a missing second-pair-part is
  automatically meaningful when no instrument *notices* it. Without a
  timeout, deadline, or attentive interlocutor, absence simply vanishes
  rather than becoming the positioned event the prime requires.

broad_use:
- **Conversation analysis.** Question/answer, greeting/greeting,
  offer/accept-or-decline, complaint/apology — the origin, where the
  preference asymmetry is documented empirically: accepts are short and
  immediate, declines delayed, hedged, and accounted for.<!-- FACT-D57-401 -->[^schegloff-sacks-1973]
- **Network protocols and API design.** Request/response with explicit
  timeout, NACK signalling, and retry policy; the timeout is the
  operational instantiation of noticeable absence, and repair appears as
  retry-with-backoff and idempotency keys.<!-- FACT-D57-402 -->[^fielding-2000]
- **Choreography and animal duetting.** Lead/follow as adjacency
  structure, where a mismatched response is felt as a stumble; and
  gibbon, wren, and frog duets where one element projects a partner's
  response within a temporal window.<!-- FACT-D57-403 -->[^geissmann-2002]
- **Liturgy and music.** Versicle/response, where silence is read as
  ritual breakdown, and call-and-response forms where the response slot
  is typed by the call's harmony, lyric, or rhythm.
- **Classroom discourse.** The initiation/response/evaluation triple,
  where absence of evaluation is noticeable and structures the next
  initiation.<!-- FACT-D57-404 -->[^mehan-1979]
- **Legal and diplomatic procedure.** Motion/response, complaint/answer,
  note/response, with jurisdictions specifying windows after which
  absence becomes procedural default.<!-- FACT-D57-405 -->[^frcp-rules]

clarity:
The construct sharpens four distinct things that "two-turn exchange"
fuses. The *typed projection*: what counts as a slot-two here is
determined by slot-one's type, not by arbitrary turn-taking. The
*noticeable absence*: a silence after a question is not the same as no
question, and any conversational or protocol system must either tolerate
or notice the gap. The *preference structure*: two slot-two responses can
both be valid yet structurally asymmetric, the asymmetry showing up in
latency, prosody, and accompanying account-work. The *repair posture*: a
discipline for handling mismatch is part of the structure, not an
emergency add-on.

Naming the pattern licenses a set of questions that transfer unchanged
across substrates even though their answers differ: what is the
type-conditioning relation, what counts as a noticeable absence, what is
the preference structure, what is the repair mechanism? A designer of a
distributed protocol, an analyst of a courtroom procedure, and a
choreographer can each ask the same four questions and get
substrate-specific answers, which is what makes the construct a tool
rather than a description. The clarity is in converting "they took turns"
into a four-part specification that can be checked and engineered.

manages_complexity:
A wide family of exchange phenomena — conversational repair, protocol
timeouts, ritual breakdowns, legal-default procedures, musical
call-and-response, animal duetting — collapses into one structural
diagnostic: identify the first-pair-part type, the projected
second-pair-part class, the absence-detection mechanism, the preference
asymmetry, and the repair affordance. Once these five are named, the
design or analysis of the exchange follows, and the same five components
organise the work whether the exchange is a database call or a liturgical
chant.

The intervention catalogue is portable. *Tighten or loosen the
type-conditioning* — allow more or fewer valid responses. *Instrument
absence-detection* — add timeouts, default-judgement deadlines, or
ritual-silence sensitivity. *Redesign the preference asymmetry* —
incentivise the dispreferred response when needed, as with an explicit
"no" affordance. *Build repair affordances explicitly* — clarification
protocols, retry policies, ritual-restart conventions. *And compose pairs
into chains* — greeting to topic-launch to question-answer to closure —
analysing each locally while the chain's coherence is global. Each move
attaches to one of the five components, so the catalogue covers the
structure rather than listing domain-specific habits.

abstract_reasoning:
Recognising the pattern enables several distinct kinds of reasoning.
*Reasoning about exchange failure-modes*: an exchange can fail at
type-conditioning (a wrong-class response), at absence-detection (no
response, undetected), at preference-asymmetry (a dispreferred response
delivered without dispreferred markers, breaking convention), or at
repair (no mechanism for clarification) — a four-way fault taxonomy that
localises the problem. *Reasoning about silence as signal*: in any
adjacency-paired system, silence is a typed event rather than the null
state, which refines reasoning about timeouts, defaults, and strategic
non-response.

Two further modes deepen the analysis. *Reasoning about preference
design*: a system in which both responses are equally easy has flattened
the preference structure, which can be good — informed consent requires
equal-weight yes and no — or bad, losing the diagnostic value of
dispreferred-marker recognition. And *reasoning about composition*:
complex exchanges decompose into chains of adjacency pairs, the analysis
of each being local while the chain's coherence is global, so a long
interaction can be checked pair by pair. Together these turn a sequence
of turns into a structured object with identifiable faults, designable
preferences, and compositional coherence — the properties that make an
exchange engineerable rather than merely observable.

knowledge_transfer:
Because the four commitments are substrate-neutral, the pattern transfers
across fields that share no content, and several of them independently
formalised the same structure. The conversation-analytic discipline of
treating silence after a first-pair-part as noticeable transfers to the
engineering discipline of explicit timeouts, heartbeats, and NACK
mechanisms — the insight "absence is data" is identical in both. The
preference structure of conversation, where declines come with delay,
hedge, and account, transfers to UX dialog design for confirmation and
consent flows. The ritual mechanism that re-establishes a missed
versicle/response transfers to liveness-preserving consensus protocols
and their re-election machinery.<!-- FACT-D57-406 -->[^lamport-1998] The window-bounded response structure of
animal duetting transfers to multi-agent coordination protocols where
window-bounded responses signal aliveness. And the classroom
initiation/response/evaluation triple transfers to adaptive tutoring
agents that evaluate responses and shape the next initiation.

The substrate-neutral framing is what makes the construct stronger than
any of its named specialisations: the commitments transfer to network
protocols, legal procedure, and animal duets without metaphor, while
musical call-and-response is recognisably one specialisation among many.
A practitioner who has designed request/response with a timeout in a
distributed system can recognise, in a courtroom default rule or a
liturgical exchange, the same first-pair-part projecting a typed
second-pair-part whose absence is a positioned event — and can reach for
the same five-component analysis and the same intervention catalogue. The
answers are domain-specific, but the typed-pair-with-noticeable-absence
structure is preserved, so the reasoning carries from one substrate to
the next without re-derivation.

formal_abstract:
A network request/response protocol is the formal worked instance, because
its four commitments are engineered explicitly rather than observed. The
*first-pair-part* is the request message — say an HTTP GET or an RPC call. The
*type-conditioning* is the protocol specification: a GET projects a typed
response class (a 2xx body, a 3xx redirect, a 4xx/5xx error), and a reply
outside that class is a protocol violation, so what counts as a valid
second-pair-part is determined by the request's type, not by arbitrary
succession.<!-- FACT-D57-407 -->[^fielding-2000] The *second-pair-part slot* is the response position, filled or
unfilled. The *noticeable absence* is operationalised as the timeout: the
client arms a timer when it sends the request, and the timer's expiry makes the
missing response a *positioned event* — silence becomes a typed event the system
must act on, not a null state. The *preference asymmetry* appears in design as
the difference between the cheap path (an immediate acknowledgement) and the
costly one (a NACK that must carry an error code and reason — the protocol's
analogue of a conversational decline that comes "delayed, hedged, and
accounted for"). The *repair affordance* is built in as retry-with-backoff and
idempotency keys: a discipline for handling a mismatched or absent
second-pair-part, part of the structure rather than an emergency add-on.
*Composition* holds too: a handshake is a chain of pairs (SYN/SYN-ACK then
ACK), each analysable locally while the chain's coherence is global.<!-- FACT-D57-408 -->[^rfc793-1981] **Mapped
back:** the request is the first-pair-part, the spec's response class is the
type-conditioning, the timeout is the noticeable-absence mechanism, the
ack/NACK gap is the preference asymmetry, and retry-with-backoff is the repair
affordance.

applied_industry:
Civil legal procedure is the applied worked case, exercising a courtroom
domain where the same four commitments are codified in rules. The
*first-pair-part* is a filed complaint or motion. The *type-conditioning* is
procedural law: a complaint projects a typed second-pair-part — an answer that
admits, denies, or raises affirmative defenses — and a response that is not a
proper answer (an irrelevant filing) does not fill the slot.<!-- FACT-D57-409 -->[^frcp-rules] The *second-pair-
part slot* is the defendant's response, filled or unfilled. The *noticeable
absence* is the response deadline: jurisdictions specify a window (often
twenty-one or thirty days) after which the absence of an answer is not a null
state but a *positioned event* with a defined consequence — a motion for
*default judgment*, where silence is read against the non-responding party.<!-- FACT-D57-410 -->[^frcp-rules] The
*preference asymmetry* is visible in the work each response carries: a simple
admission is cheap, while a denial-with-affirmative-defenses must be pleaded,
supported, and accounted for, the legal analogue of the dispreferred
conversational turn. The *repair affordance* is the procedural mechanism for a
defective or missing response — motions to set aside a default, leave to amend,
or cure periods — a built-in discipline for mismatch. The intervention
catalogue maps over: *instrument absence-detection* (the deadline clock),
*redesign the preference asymmetry* (rules that make non-response costly), and
*build repair affordances explicitly* (set-aside motions). Two further genuine
domains share the structure: liturgical versicle/response, where a missed
response is read as ritual breakdown, and animal duetting, where one bird's
call projects its partner's reply within a temporal window and the window's
expiry signals a missed pair.<!-- FACT-D57-411 -->[^geissmann-2002] **Mapped back:** the complaint is the
first-pair-part, procedural pleading rules are the type-conditioning, the
response deadline is the noticeable-absence mechanism, the admit/deny-with-
defenses gap is the preference asymmetry, and set-aside motions are the repair
affordance.


Adjudication (Dispute Resolution)

type: prime

one_liner: Dispute resolution.

status: draft

core_idea:
<!-- FACT-D49-001 -->[^fuller-1978]Adjudication and dispute resolution refers to the formal or semi-formal process by which a neutral third-party authority—such as a court, arbitrator, mediator, ombudsperson, regulator, or review panel—examines competing claims from two or more disputing parties and renders a binding decision, recommended outcome, or facilitated settlement, a structure Fuller (1978) characterized as the distinctive social ordering in which parties present proofs and reasoned arguments to a decider bound by them. The authority must possess sufficient credibility, mandate, and procedural legitimacy for all parties to accept the determination as legitimate and enforceable. This abstraction generalizes across legal systems (civil, criminal, administrative), organizational grievance procedures, employment disputes, online platform content moderation, software-engineering code-review escalation, peer-review in academic publishing, and inter-group negotiation in social contexts.

---

structural_signature:
Adjudication structures a disagreement into a formal chain: (1) **presentation of competing narratives or claims** by disputing parties; (2) **evidence or argument evaluation** by the neutral authority under established procedural rules; (3) **reasoning and judgment formation** by the authority, balancing competing interests and legal/ethical standards; (4) **decision announcement** with justification; and (5) **enforcement or compliance** mechanisms that make the decision durable.

The process creates asymmetry: the authority holds power to decide; the parties surrender direct control over outcome in exchange for legitimacy and finality. Success hinges on whether both parties perceive the authority as competent, impartial, and bound by known rules—not arbitrary.

---

what_it_is_not:
<!-- FACT-D49-002 -->[^goldberg-sander-rogers-2014]Adjudication is not negotiation or consensus-building between equals; the neutral authority is not a party with skin in the outcome, a distinction Goldberg, Sander, and Rogers (2014) treat as the canonical typology separating negotiation, mediation, arbitration, and adjudication along the dimension of who controls outcome. It is not mediation where the mediator helps parties reach their own solution; adjudication imposes a solution from above. It is not litigation merely for its own sake; litigation is the procedural form, but adjudication is the conceptual function—rendering disputes resolvable by appeal to authority rather than by force, attrition, or mutual agreement alone. It is not private arbitrage or reputation-based resolution (e.g., trust ratings, peer voting without formal procedure) unless backed by institutional mandate and rule-following.

---

broad_use:
<!-- FACT-D49-003 -->[^mnookin-kornhauser-1979]Adjudication appears wherever disputes threaten social cohesion, economic continuity, or organizational function and cannot be left to the disputing parties to resolve unilaterally, and—as Mnookin and Kornhauser (1979) showed for divorce bargaining—even private settlements typically occur "in the shadow" of the adjudicatory authority that would otherwise decide. In legal systems, courts and administrative tribunals adjudicate contracts, torts, regulatory violations, and criminal charges. In organizations, grievance committees resolve employment disputes, ethical breaches, and promotion disagreements. Online platforms use content moderation systems—increasingly automated or semi-automated—to adjudicate claims of policy violation. Software teams escalate code-review conflicts to engineering managers or architecture boards. Academic journals use peer-review editors to adjudicate manuscript suitability. Ombudspersons resolve complaints between individuals and bureaucracies. Insurance companies adjudicate claim disputes. Professional licensing boards adjudicate competency and misconduct. Schools adjudicate student conduct violations. The underlying pattern holds: a neutral authority must be perceived as competent and unbiased to resolve what the parties cannot.

---

clarity:
<!-- FACT-D49-004 -->[^tyler-1990]Adjudication achieves clarity by converting indefinite disagreement into a determinate answer: the claim is upheld or denied, the party is liable or not, the policy violation occurred or did not. This determinacy comes at a cost—the losing party must accept a binding outcome even if dissatisfied. Clarity also requires transparent procedure: all parties know the rules in advance, can present evidence and argument, and understand the reasoning for the decision—conditions Tyler (1990) found empirically determine whether disputants accept adverse outcomes as legitimate. Without procedural clarity, adjudication collapses into arbitrary authority or hidden judgment, losing legitimacy. Clarity further requires that the decision be final or appealable only on narrow grounds; endless reopening of the same dispute negates the point.

---

manages_complexity:
<!-- FACT-D49-005 -->[^hart-1961]Adjudication manages complexity by delegating judgment to a specialized authority trained in the relevant rules, evidence standards, and reasoning protocols, in the manner Hart (1961) described as the "secondary rules" of adjudication that empower designated officials to authoritatively determine when primary rules have been broken. A dispute over contract interpretation, patent infringement, or regulatory compliance may involve dense technical facts, competing legal precedents, and tradeoffs between fairness, efficiency, and deterrence. An authority with expertise and time to deliberate can weigh these factors more reliably than untrained parties or informal consensus. The procedural structure—discovery, witness examination, burden of proof, rules of evidence—also constrains how complexity enters the process, preventing overwhelming information overload. Moreover, the authority's decision becomes precedent or case law, educating future parties about dispute resolution without re-litigating every variation.

---

abstract_reasoning:
<!-- FACT-D49-006 -->[^dworkin-1986]Adjudication demands abstract reasoning about what the rules mean and how they apply to novel facts. An authority must interpret statutes, contracts, or policies written in general language and determine whether they cover the dispute at hand. This often requires counterfactual reasoning—what would a reasonable person have intended?—and balancing abstract principles: justice versus efficiency, individual rights versus collective welfare, strict liability versus negligence, an interpretive activity Dworkin (1986) likened to constructing the most coherent moral reading of legal materials as integrity rather than mere rule-application. The authority must also reason about intent and causation: did the defendant act with knowledge of harm? did the plaintiff's own conduct contribute to the injury? These forms of abstract reasoning cannot be fully automated or reduced to algorithmic checklists; they require judgment, analogy, and principled discretion.

---

knowledge_transfer:
<!-- FACT-D49-007 -->[^levi-1949]Adjudication serves knowledge transfer in two ways. First, the documented decision—reasoned judgment with findings of fact and conclusions of law—educates the broader community about how rules are interpreted and what conduct is acceptable, a process of reasoning by example from prior holdings to new facts that Levi (1949) showed is the central mechanism through which case law accumulates and transmits legal knowledge. A published court opinion teaches other parties how similar disputes will be resolved. A published code-review decision on architectural trade-offs educates the engineering team. Peer-review feedback on rejected papers educates authors and the research community. Second, the adjudication process itself—the procedural standards, evidence requirements, and reasoning norms—becomes institutionalized knowledge that improves dispute resolution over time. Legal systems accumulate case law; organizations refine their grievance procedures; platforms learn to detect policy violations more accurately.

---

title: Impartiality versus contextual knowledge

body: A neutral authority must avoid bias, yet the authority who knows nothing about the disputing parties' history, industry, or prior conduct may lack the context needed to decide wisely. A judge recuses themselves from cases involving family or financial interest, but a completely stranger-judge may misunderstand the technical or social context. Specialist arbitrators (e.g., in construction disputes) are chosen precisely because they understand the industry, yet specialization can breed subtle bias or insider allegiance. How much contextual knowledge can an authority have without compromising impartiality?

title: Finality versus correctness

body: The authority must issue a final decision that cannot be endlessly reopened, or else the dispute never resolves and the parties remain locked in conflict. Yet finality means accepting that some decisions will be incorrect or based on incomplete information. Higher courts review lower courts, but only on limited grounds; internal grievance committees issue final recommendations, but employees may sue; arbitration is final, yet arbitrators can be wrong. If the authority reserves the right to reconsider on whim, finality evaporates. If the authority is bound by finality even when obviously wrong, justice is compromised. Where is the line?

title: Procedural uniformity versus case-specific fairness

body: The authority needs consistent, known rules to ensure predictability and prevent arbitrary judgment. Yet rigid procedures may fail to capture what matters in a particular dispute: a standard discovery timeline may be insufficient for a complex technical case; a fixed evidence standard may exclude crucial context in a discrimination claim; a template grievance procedure may oversimplify an emotionally charged workplace conflict. If the authority deviates from procedure to achieve fairness in one case, does that erode uniformity and predictability for all other cases?

title: Authority legitimacy versus accountability

body: The disputing parties accept the authority's decision because the authority is perceived as legitimate—independent, trained, bound by rule-based reasoning. Yet if the authority is not answerable to anyone—if there is no oversight, no appeal, no public explanation of reasoning—the authority may become a tyrant with a smile. Courts have higher courts; arbitrators are chosen by the parties; ombudspersons report to the legislature; social media moderators can be appealed to a board. But oversight can also be burdensome and slow. How much accountability is enough without destroying decisiveness?

title: Speed versus deliberation

body: The disputing parties want rapid closure—litigation that drags on for years is itself a harm. Yet good judgment requires time to reflect, gather evidence, and weigh complexity. A rushed decision may be unjust or internally inconsistent. Expedited procedures (summary judgment, small-claims court) sacrifice deliberation for speed; de novo review on appeal sacrifices finality for another chance at correctness. Online content moderation often happens in minutes or hours, yet moderators may lack time to understand context. Where is the boundary between acceptable haste and insufficient care?

title: Accessibility versus gatekeeping

body:
Adjudication should be open to anyone with a legitimate dispute; if the procedure is expensive or opaque, only the wealthy or sophisticated can access justice, and the poor are excluded. Yet completely open adjudication—allowing anyone to bring any claim to any authority at any time—creates an unmanageable flood of disputes and defection to frivolous or malicious claims. Courts have standing requirements and statutes of limitation; grievance procedures have formal filing deadlines; platforms have automated abuse filters; arbitrators require an arbitration agreement. These gatekeeping mechanisms improve efficiency and quality but exclude some people with legitimate claims. How can adjudication be accessible without becoming a chaos of unlimited disputes?

---

prose:
<!-- FACT-D49-010 -->[^llewellyn-1960]To handle impartiality versus contextual knowledge, institutions use recusal rules (authorities recuse themselves when they have direct interest), conflict-of-interest disclosures, and specialist assignment (environmental judges for environmental cases, IP judges for patent cases). This preserves impartiality while leveraging relevant expertise—an arrangement Llewellyn (1960) analyzed as the "grand style" of common-law judging that pairs craft expertise with situation-sense and fidelity to received doctrine. The authority is not immune from challenge: a party can move to disqualify a biased judge or arbitrator.

<!-- FACT-D49-011 -->[^galanter-1974]To manage finality versus correctness, institutions establish tiers of appeal: trial courts issue first decisions, appellate courts review on narrow grounds (misapplied law, clearly erroneous fact-finding), and supreme courts review only questions of constitutional or precedential importance—a tiered structure Galanter (1974) showed systematically advantages "repeat players" who can absorb appellate costs and shape doctrine over "one-shotters" who settle at trial. This preserves finality for most disputes while allowing correction of serious errors. Alternative: arbitration with one shot, accepting finality even when wrong, in exchange for speed and privacy.

<!-- FACT-D49-012 -->[^katsh-rabinovich-einy-2017]To balance procedural uniformity and case-specific fairness, institutions build discretion into procedure: judges have power to extend discovery deadlines, exclude evidence on fairness grounds, or issue tailored remedies. The discretion is bounded by rules and appellate review, preventing arbitrary abuse. Online platforms use community guidelines (uniform rules) but permit appeals to a human reviewer (case-specific fairness override), a hybrid Katsh and Rabinovich-Einy (2017) trace through the evolution of online dispute resolution as it scales algorithmic uniformity with selective human override.

<!-- FACT-D49-013 -->[^weber-1922]To ensure authority legitimacy while maintaining accountability, institutions require reasoning: every decision must be accompanied by a written explanation of findings and legal conclusions. This allows appeal courts and the public to scrutinize the authority's logic. Some institutions also require transparency (public hearings, published opinions) and oversight (inspector generals, professional conduct boards). The authority is legitimate because bound by rule and exposed to scrutiny, not because invisible and unaccountable—the rational-legal mode of domination Weber (1922) distinguished from charismatic and traditional authority precisely by its rule-bound, reason-giving character backed by the state's monopoly on legitimate force.

<!-- FACT-D49-014 -->[^bercovitch-anagnoson-wille-1991]To balance speed and deliberation, institutions tier procedures: simple cases (small-claims, fast-track arbitration) have abbreviated timelines and simplified procedure, sacrificing some deliberation for speed; complex cases (patent litigation, regulatory review) have extended periods for discovery and expert evaluation. The authority gains time to think when the stakes and complexity warrant it—an empirical pattern Bercovitch, Anagnoson, and Wille (1991) documented in international mediation, where successful resolution rates depend on matching procedural intensity to dispute complexity and intractability.

<!-- FACT-D49-015 -->[^zehr-1990]To address accessibility versus gatekeeping, institutions create multiple channels: formal adjudication (courts, arbitration) with high barriers to entry but strong legitimacy; administrative procedures (regulatory hearings, grievance committees) with lower barriers; small-claims courts with simplified procedure and low fees; ombudsperson services (often free and accessible) for complaints against organizations. This allows different disputes to find appropriate forums—a pluralism Zehr (1990) extended through the restorative-justice paradigm, which proposes community-based circles and victim–offender encounters as accessible alternatives to formal criminal adjudication.

---

notes:
Adjudication is a foundational social technology for moving disputes from the realm of force and attrition into the realm of reason and authority. It succeeds when the disputing parties believe the authority is competent, impartial, and bound by known rules. It fails when it becomes a tool of oppression (biased authority serving the powerful), a procedural quagmire (so slow and expensive that justice is inaccessible), or a pseudo-legitimacy mask (the appearance of fairness without actual impartiality or reason).

Modern adjudication faces challenges: courts are backlogged; arbitration has been captured by corporate interests (one-sided mandatory arbitration clauses); online content moderation combines algorithmic speed with insufficient human judgment; regulatory agencies accumulate power without proportional oversight; academic peer review remains opaque and slow. Yet the need for adjudication has not diminished. As societies grow larger and more complex, reducing disputes to private settlement becomes harder, and neutral authority more necessary.

Generalization: adjudication appears whenever a third-party authority intervenes in a dispute to render a binding or authoritative determination. This includes not only formal legal processes but also organizational hierarchies (managers settling team disputes), professional bodies (ethics committees), communities (elder councils, jury-like citizen panels), and algorithmic systems (machine-learning classifiers trained to categorize policy violations). The challenge in each context is to maintain the core attributes—impartiality, legitimate authority, reasoned judgment, procedural fairness—while adapting to local constraints of time, resources, and expertise.

---


Adversarial Boundary Navigation

one_liner: An adaptive opponent searches a rule's boundary for the cheapest legal-side configuration that keeps the prohibited substance.

core_idea:
Adversarial boundary navigation is the structural pattern in which a
principal deploys a decision rule — classifier, statute, threshold,
detection apparatus — whose boundary in input or behaviour space is
*discoverable* by an *adaptive opponent*, and the opponent searches that
boundary for the *cheapest legal-side configuration that preserves the
illegitimate intent or payload*. The rule remains *correct relative to
its input* — it has not been changed, corrupted, or gamed in the
Goodhart sense — but the opponent has found and occupied the *gap between
the rule's representation and the concept the principal wanted the rule
to represent*. The opponent operates indefinitely on the legal side of
the boundary while delivering essentially the same prohibited outcome,
and each defensive update forecloses the current strategy only to reveal
the next gap. The structure is intrinsically co-evolutionary.

The structural commitment is that *the locus of failure is the
rule-concept gap*, not the rule's fidelity to its inputs and not the
concept's ill-definition. Both rule and concept can be perfectly defined;
the opponent simply discovers and inhabits their difference. This
relocates diagnosis from "the rule is broken" or "the concept is
unclear" to "the representation gap is the substrate of attack," which
licenses interventions on the *gap* itself — close it, layer rules whose
gaps do not align, monitor for boundary-hugging drift, or accept the
co-evolutionary register.

The pattern works even without a strategic principal. In biological
cases the recognition system is not an intentional agent — it merely
needs to be discoverable and to have a gap — which shows the structure
does not depend on intentionality on the principal's side. What it
requires is only a discoverable boundary, a gap between rule and concept,
and an opponent with the budget to search.

structural_signature:
*the decision rule with a discoverable boundary* — *the concept the rule was meant to represent* — *the static rule-concept gap* — *the adaptive opponent with a search budget* — *the cheapest legal-side configuration preserving the prohibited substance* — *the co-evolutionary closure*

The pattern is present whenever these components are configured together:

- **The decision rule (role).** A classifier, statute, threshold, or
  detection apparatus whose boundary in input or behaviour space is
  *discoverable* by an opponent and *correct relative to its input* — not
  buggy, not gamed.
- **The intended concept (role).** What the principal wanted the rule to
  capture, both rule and concept potentially well-defined.
- **The rule-concept gap (invariant).** The locus of failure is the
  *static* difference between the rule's representation and the concept —
  not the rule's fidelity to inputs (that would be a bug) and not the
  concept's ill-definition; the gap need not change for the attack to
  work.
- **The adaptive opponent (role).** An agent with a budget to search the
  boundary; need not be strategic on the principal's side — biological
  recognition systems qualify.
- **The boundary-navigation move (relation).** The opponent finds the
  cheapest legal-side configuration that preserves the illegitimate intent
  or payload, operating indefinitely on the allowed side while delivering
  the prohibited outcome.
- **The co-evolutionary closure (invariant).** Each defensive update
  forecloses the current strategy only to reveal the next gap, so the
  structure is intrinsically an arms race with a half-life, distinct from
  Goodhart metric corruption (where the rule-concept relation *degrades
  under optimisation*).

The components compose into the signature: an adaptive opponent occupies
the static gap between a discoverable rule and its intended concept,
walking around a measure that never changed — so interventions must act
on the gap, not on punishment within the rule's current scope.

what_it_is_not:
- **Not `boundary`.** A `boundary` is the bare demarcation a rule draws;
  this prime is the *adversarial exploitation* of the static gap between
  that boundary and the concept it was meant to capture. The boundary is
  the terrain, not the attack.
- **Not Goodhart gaming (`performativity`).** Goodhart corruption is the
  rule-concept relation *degrading under optimisation* — the measure
  becomes a worse proxy. Here the rule stays *correct* and *static*; the
  opponent walks around a measure that never changed.
- **Not `arbitrage_generalized`.** Arbitrage exploits a price or value
  gap to extract surplus; this prime exploits a *rule-concept* gap to
  deliver a prohibited substance on the legal side — and is intrinsically
  co-evolutionary, with each patch revealing the next gap.
- **Not `systemic_fragmentation`.** Fragmentation is a system breaking
  into disconnected parts; adversarial boundary navigation is a single
  opponent occupying one static gap in an otherwise intact rule.
- **Not `learning` in general.** Learning is any improvement from
  experience; this prime is the specific adversarial search for the
  cheapest legal-side configuration preserving the illegitimate payload,
  against a discoverable boundary.
- **Not `segmentation_and_boundary_drawing`.** That prime concerns *where*
  to draw a dividing line; this one concerns an opponent *exploiting the
  gap* between any drawn line and the concept, regardless of where the
  line sits.
- **Common misclassification.** Diagnosing boundary navigation as
  Goodhart and prescribing Goodhart remedies (rotate the metric, add
  noise) against an opponent who is already *compliant* with a faithful
  rule — the fix is to close the gap or layer non-aligned rules, not to
  punish within the rule's scope.

broad_use:
- **Adversarial machine learning.** Evasion attacks search a
  classifier's boundary for inputs that retain prohibited semantic
  content — still spam, still malware, still a stop sign — while crossing
  onto the allowed side.<!-- FACT-D57-426 -->[^szegedy-etal-2014]
- **Regulatory arbitrage and structuring.** Corporate structuring to
  fall on the safe side of tax, securities, or sanctions boundaries
  while preserving the economic substance the regulator meant to
  constrain; transactions sized just below reporting thresholds.<!-- FACT-D57-427 -->[^fleischer-2010]
- **Doping and fishery evasion.** Micro-dosing and designer compounds
  that fall outside a banned list, and under-size catches, species
  mislabelling, and off-season landings recorded as in-season.<!-- FACT-D57-428 -->[^balco-thg-iuu]
- **Sanctions evasion and malware.** Intermediary entities,
  flag-of-convenience shipping, and signal spoofing; and decade-scale
  co-evolution between mutating malware and evolving detection
  signatures.<!-- FACT-D57-429 -->[^dark-fleet-sanctions]
- **Biological mimicry.** Predator-prey camouflage occupying the gap in
  a prey's detection rule, and brood parasites mimicking host clutches
  or nest-mate pheromones — cases where the principal is non-strategic.<!-- FACT-D57-430 -->[^davies-brooke-1989]
- **Content and integrity evasion.** Coded language and substitution to
  evade keyword filters, and obfuscation tuned to plagiarism or
  AI-detection classifiers.<!-- FACT-D57-431 -->[^krishna-etal-2023]

clarity:
The construct sharply distinguishes three locus-of-failure patterns that
are routinely confused. *Rule-fidelity failure*: the rule mis-implements
its specification — a bug — and the fix is to correct the rule.
*Goodhart-style metric corruption*: the rule is used as a target and its
statistical relationship to the concept degrades under optimisation
pressure, so the fix is to change the rule, the incentives, or the number
of rules. *Adversarial boundary navigation*: the rule is *correct* and
its relationship to the concept *static*, and the opponent discovers and
occupies the static gap; the fix is to close the gap, layer non-aligned
rules, monitor drift, or accept the arms-race register.

The three are mechanistically related — all depend on the rule-concept
gap — but their loci of failure differ, and so do their interventions.
Naming adversarial boundary navigation prevents the common error of
misdiagnosing it as Goodhart, an error that leads to
incentive-restructuring interventions that do not bite because the
opponent is not optimising the metric at all, only navigating the rule.
The clarity is in separating "the measure degraded under pressure" from
"the opponent walked around a measure that never changed," because the
two failures look alike from the outside and demand opposite responses.

manages_complexity:
The construct collapses a wide family of seemingly disparate phenomena —
evasion attacks, regulatory arbitrage, structuring, doping, fishery
cheating, sanctions evasion, brood parasitism, spam, plagiarism evasion
— into one diagnostic: identify the discoverable boundary, the adaptive
opponent, the rule-concept gap, and the opponent's budget. Once these
four are named, the prediction follows — the opponent will find
configurations on the legal side that preserve the prohibited substance,
and defensive updates will reveal new gaps — and the prediction holds
across substrates that otherwise share nothing.

The intervention catalogue is portable. *Close the gap* — broaden the
rule's representation to better match the concept, through anti-abuse
rules, multi-modal classifiers, or ensemble detectors. *Layer rules with
non-aligned gaps* — combine rules whose representations differ so the
opponent must find a configuration legal under *all* of them. *Monitor
for drift* — instrument the gap to catch boundary-hugging behaviour even
when each individual transaction is compliant. *Raise opponent cost* —
query-budget limits, honeypots, randomised thresholds. *Accept the
co-evolutionary register* — budget for continuous updates rather than
expecting one-shot defence. *And reframe the rule as a
concept-approximation* — surface the gap explicitly so users do not
over-trust the rule. Each move attaches to the gap, the opponent's
budget, or the co-evolutionary timeline, so the catalogue covers the
structure rather than enumerating substrate-specific countermeasures.

abstract_reasoning:
Recognising the construct enables several distinct kinds of reasoning.
*Reasoning about which interventions bite*: closing the gap, layering
rules, and monitoring drift work, while punishing harder *within the
rule's current scope* does not, because the opponent is already compliant
with the rule. *Reasoning about the co-evolutionary timeline*: each
defensive update has a *half-life* — how long until the opponent finds
the next gap — and half-lives compress in fast environments such as spam
and stretch in slow ones such as tax law.<!-- FACT-D57-432 -->[^goodhart-1984] *Reasoning about opponent
budget*: the gap survives as long as searching it is cheaper than
complying with the concept, so raising search cost can flip the
calculation.

Two further modes deepen the analysis. *Reasoning about non-strategic
principals*: the brood-parasitism and camouflage cases show the pattern
works without a strategic principal, ruling out the common confusion that
it is "really about" strategic agents — the rule need only be discoverable
and have a gap. And *reasoning about the defender's prior*: a defender who
pretends no gap exists is more vulnerable than one who explicitly tracks
it, so naming the gap is itself a defensive move. Together these convert
"the rule keeps getting evaded" into a structured analysis of a static
gap, an adaptive search, a budget, and a half-life — which is what makes
the pattern predictive rather than merely cautionary.

knowledge_transfer:
Because the pattern is a relation among a discoverable rule, a static
concept, and an adaptive opponent, both its analysis and its defences
transfer across fields that share no content. The adversarial-examples
apparatus — a minimal perturbation within a budget that preserves
semantics while crossing a classifier boundary — is the same apparatus as
minimal corporate restructuring within a tax-code budget that preserves
economic substance while crossing a safe-harbour boundary, and the
defensive techniques map across too: adversarial training, ensemble
defence, and certified robustness have direct analogues in anti-abuse
doctrines, economic-substance tests, and multi-prong rules.<!-- FACT-D57-433 -->[^madry-etal-2018] The
intelligence discipline of enumerating intermediary structures and
jurisdictional gaps transfers to red-teaming model safety filters, and
the host-egg-recognition arms race from biology transfers to
authenticity-verification systems facing improving generation models,
where the biological lesson that recognition systems are perpetually
under pressure informs product roadmap planning.

The deepest transfer is the recipe — close the gap, layer non-aligned
rules, monitor drift, raise opponent cost, accept co-evolution —
recognisable across every substrate instance because each is a way of
acting on the rule-concept gap rather than on the rule's fidelity. A
practitioner who has hardened an image classifier against evasion can
recognise, in a money-laundering monitoring rule or a doping-test
protocol, that the rule is correct and the opponent is occupying a static
gap, and that punishing harder within the rule's scope will not bite. The
substrates differ — pixels, transactions, compounds, catches, eggs — but
the static-gap-plus-adaptive-search structure and its gap-directed repair
are preserved, so the reasoning carries from one to the next without
re-derivation, and the non-strategic biological cases confirm that the
transfer rests on structure rather than on any shared intentional agent.

formal_abstract:
An evasion attack on an image classifier is the formal worked instance,
because the rule-concept gap is geometrically explicit. The *decision rule* is
the trained classifier — a function partitioning input space into "spam image"
versus "benign," whose decision boundary is *discoverable* by an opponent with
query access and *correct relative to its inputs* (it is not buggy; it computes
exactly the function it was trained to). The *intended concept* is the human
notion "image carrying spam content." The *rule-concept gap* is the static
difference between the classifier's learned boundary and the true concept
boundary — a difference that exists because the model generalises imperfectly,
and need not change for the attack to work. The *adaptive opponent* is the
spammer with a query budget. The *boundary-navigation move* is the adversarial
perturbation: a minimal pixel change, often imperceptible, that pushes the
image across the classifier boundary onto the "benign" side while *preserving
the spam semantics* a human still reads — the cheapest legal-side configuration
that keeps the prohibited substance.<!-- FACT-D57-434 -->[^szegedy-etal-2014] The *co-evolutionary closure* is the arms
race: retraining on the discovered adversarial examples forecloses that attack
but reveals the next gap, so each defensive update has a *half-life*. The
construct's diagnostic bite is which interventions *bite*: closing the gap
(adversarial training, ensembles), layering non-aligned rules (multiple
detectors whose boundaries differ so the opponent must be legal under all), and
monitoring boundary-hugging drift work — while punishing harder *within the
rule's current scope* does not, because the perturbed image is already compliant
with the rule. This separates the failure from Goodhart: the metric did not
*degrade under optimisation*; the opponent walked around a measure that never
changed. **Mapped back:** the classifier is the discoverable rule, "spam
content" is the intended concept, the generalisation error is the static gap,
the spammer is the adaptive opponent, and the imperceptible perturbation is the
cheapest legal-side configuration preserving the prohibited substance.

applied_industry:
Regulatory arbitrage via transaction structuring is the applied worked case,
exercising a financial-compliance domain whose apparatus is provably the same.
The *decision rule* is a reporting threshold — say, the rule that cash
transactions over a stated amount trigger a currency-transaction report.<!-- FACT-D57-435 -->[^bsa-ctr-threshold] The
boundary is *discoverable* (the threshold is published) and *correct relative
to its input* (it flags exactly what it says). The *intended concept* is "money
laundering / illicit fund movement" that the threshold was meant to surface.
The *rule-concept gap* is static: the bright-line threshold does not coincide
with the concept of illicit intent. The *adaptive opponent* is a launderer with
a structuring budget. The *boundary-navigation move* is *smurfing*: splitting
one large deposit into many transactions each sized just below the reporting
threshold, occupying the legal side of the boundary while delivering exactly
the prohibited outcome — funds moved without a report.<!-- FACT-D57-436 -->[^structuring-5324] The *co-evolutionary
closure* is visible in the regulatory history: each anti-structuring rule
forecloses the current technique and reveals the next gap, with half-lives that
stretch in slow-moving law and compress in fast environments. The apparatus is
*provably identical* to the adversarial-examples case — minimal restructuring
within a budget that preserves substance while crossing a safe-harbour
boundary — and the defenses map across: anti-abuse doctrines and
economic-substance tests are the legal analogue of adversarial training and
ensemble defence, *monitoring for drift* (flagging boundary-hugging
transaction patterns even when each individual transaction is compliant) is the
behavioural-analytics counterpart, and *raising opponent cost* corresponds to
query-budget limits. Two further genuine domains share the structure: doping,
where designer compounds and micro-dosing fall just outside a banned list, and
biological brood parasitism, where a cuckoo's egg mimics the host clutch to
occupy the gap in the host's recognition rule — the non-strategic-principal case
proving the transfer rests on structure, not intent.<!-- FACT-D57-437 -->[^davies-brooke-1989] **Mapped back:** the
reporting threshold is the discoverable rule, "illicit fund movement" is the
intended concept, the bright-line-versus-intent difference is the static gap,
the launderer is the adaptive opponent, and sub-threshold structuring is the
cheapest legal-side configuration preserving the prohibited substance.


Adversarial Signal Imitation

one_liner: Adversarial signal imitation copies the observable cues that normally distinguish a trusted hidden type while avoiding the cost or constraint that made those cues informative.

core_idea:
Adversarial signal imitation occurs when an emitter copies the observable cues associated with a trusted hidden type while avoiding the cost, constraint, history, or production process that made those cues informative. Receivers classify on the copied surface and extend trust, access, protection, or weight the emitter did not earn.

The mechanism attacks a separating relation. A signal works because it is easier, cheaper, or possible for one hidden type to produce and harder for another. An imitator finds a path that reproduces the receiver-visible cue without satisfying the original separating condition. The cue may remain perceptually convincing while its evidentiary value collapses.

structural_signature:
**Sig role-phrases:**

- **the hidden type** — quality, origin, incentive, capability, identity, toxicity, or commitment the receiver cannot inspect directly
- **the trusted cue** — the observable feature receivers use as evidence of that type
- **the separation constraint** — the cost, production history, authorization, or physical limitation that normally makes the cue discriminating
- **the imitator** — an emitter lacking the trusted type but able to reproduce the cue
- **the bypass path** — a route that copies the cue without paying or satisfying the original constraint
- **the receiver classifier** — the rule that maps the visible cue to a type judgment
- **the borrowed treatment** — trust, access, avoidance, attention, or evidentiary weight granted on the mistaken classification
- **the pooling pressure** — successful imitation reduces the cue's ability to separate types for every honest emitter

what_it_is_not:
- **Not ordinary resemblance.** The copied feature must be used by a receiver to infer a consequential hidden property.
- **Not signaling itself.** Signaling supplies the informative cue-to-type relation; imitation exploits or destroys its separating power.
- **Not every deceptive statement.** The operation can be entirely nonverbal and can accompany factually true content.
- **Not forgery only.** A forged artifact is one implementation. An authentic item can also be wrapped in copied authority cues.
- **Not camouflage by default.** Camouflage suppresses detection by blending into background. Signal imitation invites classification as a specific trusted or protected type.
- **Not a one-receiver curiosity.** The abstraction includes the population effect: enough successful imitators can make the cue uninformative and force a new verification regime.

broad_use:
In biology, Batesian mimicry lets a palatable organism copy the warning coloration of a defended model. The receiver-visible phenotype is real, but the toxin or defense it normally indicates is absent. Frequency dependence follows: if mimics become common, predators stop trusting the cue.

In markets and certification, low-quality goods reproduce seals, packaging, professional vocabulary, or process markers associated with inspected production. The mark is valuable precisely because buyers cannot inspect the full production history.

In computing and security, phishing pages, device identity spoofing, caller-ID spoofing, and adversarial examples reproduce features a classifier treats as identity or legitimacy. The implementation varies from pixel-level copying to protocol fields, but the bypass has the same target: the receiver's cue-to-type rule.

In communication, native advertising copies editorial layout, astroturfing copies spontaneous grassroots voice, and synthetic authority accounts copy institutional naming and visual markers. The content can be partly or wholly true; the borrowed signal still misstates the production incentive or origin.

In organizations, ritual compliance can imitate the artifacts of a working control—completed checklists, audit language, dashboards—without the underlying monitoring or response capacity. The visible assurance marker survives while the constraint it was meant to certify has been bypassed.

clarity:
The abstraction distinguishes surface duplication from constraint satisfaction. Defenders often respond by making the signal louder—larger badges, stronger styling, more familiar templates. If the attacker can copy the same surface, amplification makes the target more valuable without restoring separation.

The correct question is not “does the artifact look like the trusted type?” but “what prevents an untrusted type from producing the same observable?” The answer may be physical cost, cryptographic attestation, custody history, independent audit, repeated performance, or a production residue difficult to control intentionally.

manages_complexity:
Many fields maintain separate vocabularies for mimicry, spoofing, counterfeiting, phishing, astroturfing, and authority borrowing. Adversarial signal imitation compresses them to four checks: what hidden type matters, what cue represents it, what constraint separates emitters, and how the attacker bypasses that constraint.

This decomposition organizes defenses. Change the receiver rule, strengthen the separation constraint, bind the cue to verifiable origin, introduce independent challenge, monitor pooling, or move weight to a production signature the imitator cannot cheaply tune.

abstract_reasoning:
The direct-inspection counterfactual tests whether the mechanism depends on information asymmetry. If receivers could inspect the hidden type at negligible cost, would the copied cue still change treatment? If not, the cue is a proxy used because the type is hidden.

The bypass test asks whether the imitator reproduces the observation while severing the causal path that made it evidence. A certification mark generated by the certifier and a copied bitmap can be visually identical; only one carries the authorized production history.

The population test predicts decay. As the proportion of mimics rises, the posterior probability of the trusted type conditional on the cue falls. Receiver behavior should then shift toward skepticism, secondary verification, or abandonment of the cue, imposing costs on honest signalers as well.

knowledge_transfer:
A harmless insect copying warning coloration, a counterfeit product copying a certification mark, a phishing site copying a bank interface, and a sponsored article copying editorial layout fill the same roles. Each has a hidden type, a trusted cue, a separating constraint, a bypassing imitator, a receiver update, and borrowed treatment.

The transfer is mechanistic. Defensive ideas also travel: make the cue costly in a type-dependent way, bind it cryptographically or procedurally to origin, add a challenge the mimic cannot answer, or discount it as pooling increases.

title: Surface fidelity versus evidentiary fidelity

body: A perfect copy can be maximally misleading. Diagnostic: audit the causal path behind the cue, not its resemblance.

title: Cheap verification versus usable trust

body: Rechecking every signal defeats the efficiency that cues provide. Diagnostic: reserve expensive verification for high-stakes or high-pooling regimes.

title: Stronger marker versus stronger target

body: A more salient cue can attract more imitation. Diagnostic: improve uncopyable binding rather than visible intensity alone.

title: Individual success versus population decay

body: One mimic benefits from a trusted pool; too many destroy it. Diagnostic: monitor the type distribution conditional on the cue over time.

title: Adaptive defense versus accessibility

body: Harder-to-copy signals can exclude legitimate emitters unable to bear the new cost. Diagnostic: separate adversarial resistance from unnecessary participation burden.

title: Intentional adversary versus evolved or automated exploit

body: The relation does not require conscious strategy. Diagnostic: identify differential advantage from copied classification, not an unverifiable mental state.

notes: _(New cross-domain prime created to resolve a mixed-DAG missing-parent gate; queued for Claude style, source, and citation harmonization.)_


Adverse Selection

one_liner: Hidden pre-contractual types make participation under uniform terms systematically more attractive to the types worst for the uninformed side, degrading or unraveling the pool.

core_idea:
Adverse selection is the pre-contractual information asymmetry in which one party to a potential transaction privately knows characteristics (of themselves, of a good, of a state of nature) relevant to the other party's willingness to transact, and the structure of the market causes the worst-for-the-uninformed-party types to self-select into the transaction — producing market unraveling (only lemons traded, only sick people insured, only the most risky borrowers willing to borrow at the offered rate) or, in the extreme, complete market collapse. The essential commitment is that hidden characteristics (in contrast with hidden actions, which produce moral hazard) systematically skew the pool of willing participants toward those whose presence is least desirable to the uninformed side, and that this pooling dynamic can destroy markets that would otherwise be mutually beneficial at the individual level. Every adverse-selection articulation specifies:

(1) **The hidden characteristic** — health risk (insurance), quality (lemons), productivity (labor), creditworthiness (credit) — a type privately known to one side and costly or infeasible for the other side to observe directly.

(2) **The pooling mechanism** — a single price or premium applied across types, under which types with higher-than-average costs to the uninformed side are more willing to transact than types with lower-than-average costs, inducing self-selection of the worst pool composition.

(3) **The equilibrium consequence** — either a partial unraveling (separating equilibrium via signaling or screening, with losses relative to full information) or complete unraveling (market collapse, Akerlof lemons model).

(4) **The mitigation devices** — signaling by the informed side (credentials, warranties), screening by the uninformed side (medical exams, credit checks), mandated participation (mandatory insurance, universal enrollment), or government provision.

(5) **The empirical welfare pattern** — the welfare loss is the wedge between the second-best outcome (under information asymmetry) and the first-best outcome (under symmetric information); multiple equilibria often exist, making the efficiency properties data- and mechanism-dependent.

(6) **Cross-domain applicability** — the construct transfers across insurance, credit, labor markets, used goods, securities, procurement, relationships, and any setting where self-selection into participation depends on private information about type.

The construct was introduced in its modern form by Akerlof[^akerlof-1970] <!-- FACT-D07-100 --> in "The Market for 'Lemons'" — which together with the subsequent work of Spence[^spence-1973] <!-- FACT-D07-101 -->[^spence-1973] (job-market signaling) and Rothschild-Stiglitz[^rothschild-stiglitz-1976] <!-- FACT-D07-103 --> (equilibrium in competitive insurance markets) — won the 2001 Nobel Prize in Economic Sciences.

structural_signature:
A complete adverse-selection articulation consists of six interlocking components that together specify how hidden characteristics generate market failure and what remedies look like:

1. **Hidden type characteristic and uniform contract terms.** One party (the informed side) privately observes a characteristic that determines their costs or benefits from contracting; the other party (the uninformed side) knows only the distribution of types. The uninformed side offers uniform terms (a single price, premium, wage, or interest rate) to all types. Under asymmetric information, uniform terms cannot efficiently price-discriminate by type, creating the selection-driven pooling dynamic. In Akerlof's canonical lemons model, sellers observe quality $q \sim \text{Uniform}[0, \theta]$; buyers observe only the distribution and offer a single market price $p$[^akerlof-1970]. <!-- FACT-D07-100 -->[^akerlof-1970]

2. **Self-selection dynamic and pool composition.** At any uniform price or premium, the willingness to transact depends on type: types with high private values (high costs to the uninformed side) are more willing to accept the uniform terms than types with low private values. This produces adverse selection of composition — the pool of willing transactors skews toward the worst types from the uninformed party's perspective. If sellers value cars at $q \cdot v_s$ and buyers value them at $q \cdot v_b$ (with $v_b > v_s > 0$), only sellers with $q \leq p / v_s$ will sell at price $p$. Buyers rationally expect the average quality of cars offered to be around half the cutoff, setting their willingness to pay at $p / v_b = \bar{q}_{\text{sold}} \cdot v_b$.

3. **Equilibrium existence and characterisation — separating, pooling, or hybrid.** Three canonical equilibrium structures emerge: *separating equilibrium*, where different types choose different contracts (via signaling or screening), permitting partial market function but with efficiency losses (signaling waste, screening menus); *pooling equilibrium*, where all types accept the same contract and the pool degrades; *non-existence*, where no pure-strategy equilibrium exists (Rothschild-Stiglitz 1976 showed that a pure-strategy separating equilibrium may fail to exist in insurance markets because the separating contract can be undercut by pooling deviations)[^rothschild-stiglitz-1976]. <!-- FACT-D07-103 -->[^rothschild-stiglitz-1976] In credit markets, Stiglitz-Weiss[^stiglitz-weiss-1981] <!-- FACT-D07-104 -->[^stiglitz-weiss-1981] showed that banks do not clear the credit market via price because higher interest rates adversely select riskier borrowers, leading to credit rationing — a quantity restriction and non-market-clearing equilibrium.

4. **Unraveling logic and the Akerlof iterative dynamic.** If buyers expect average quality $\bar{q}$ and offer willingness-to-pay $p = \bar{q} \cdot v_b$, only sellers with $q \leq p / v_s$ sell. This updates average quality to a lower figure, inducing buyers to lower their willingness to pay. The iteration cycles: lower price attracts only worse cars, so the buyer's expectation of average quality falls, so the buyer's willingness to pay falls further, so only the worst cars remain willing to sell. Under standard valuations, the market unravels entirely — equilibrium quality shrinks toward $0$ and quantity toward $0$. This iterative unraveling is the most consequential feature of adverse selection and explains market collapse in lemons, insurance-premium spirals, and credit-market freezes.

5. **Mitigation devices and their efficiency properties.** Four broad remedy classes emerge: (a) *signaling* — the informed party credibly reveals type via costly action (education, warranty, certification); transfers equilibrium to separating, but the signaling cost is generically wasteful if it does not raise productive value; (b) *screening* — the uninformed party offers a menu of contracts at different terms that induces self-separation by type; equilibria may be separating or pooling hybrid, but screening menus are generically inefficient relative to full-information contracts (this is the "no distortion at the top" principle in mechanism design); (c) *mandated participation* — universal enrollment or mandatory insurance pools all types, preventing unraveling, but imposes cross-subsidies from low-cost to high-cost types; (d) *government provision* — state-supplied insurance or credit eliminates the selection problem entirely but may introduce moral-hazard and fiscal-cost issues.

6. **Operative use: domains and policy transfer.** Adverse-selection reasoning transfers across insurance (health, life, annuities, catastrophe, flood), credit markets (mortgage, consumer, small-business lending), labor markets (educational signaling, hiring credentials), used-goods markets (cars, real estate, art), securities markets (IPO pricing, liquidity provision), health-policy design (Affordable Care Act structure: individual mandate + subsidies + risk adjustment = three-pronged anti-unraveling architecture), procurement (winner's curse as adverse selection against the buyer in auctions), matching markets (self-selection in dating, organ donation, nonprofit volunteering), and any online marketplace where participant quality is hidden. The structural core is identical; what varies is the substrate (the hidden characteristic), the pooling mechanism (the contract form), and the mitigation device (signaling, screening, or mandate).

what_it_is_not:
**Common misclassification: Treating adverse selection as equivalent to moral hazard or to all information asymmetries.**
Adverse selection concerns hidden *characteristics* before contracting (types); moral hazard concerns hidden *actions* after contracting. See *moral_hazard* for the post-contractual sibling and *agency_problem* for the broader frame.

**Not identical to ordinary selection bias:**
Adverse selection specifically arises when the selection *is driven by the price or contract terms in a way adverse to the uninformed side*. General selection bias (e.g., survivor bias in data) is a broader statistical phenomenon; adverse selection is the economic manifestation in contracting contexts where self-selection into the contract is endogenous to the contract terms themselves.

**Not always resolvable by signaling or screening:**
Signaling (informed party credibly communicates type) and screening (uninformed party offers a menu that separates types) can restore partial market function, but the resulting equilibria are generically inefficient relative to full information. In Rothschild-Stiglitz[^rothschild-stiglitz-1976] <!-- FACT-D07-103 -->, a pure-strategy equilibrium may fail to exist at all; in Spence[^spence-1973] <!-- FACT-D07-101 -->, signaling is wasteful even when it works (education-as-signaling is pure waste if education adds no productive skill yet is necessary to prove ability).

**Not always bad for welfare:**
Adverse-selection models often have multiple equilibria; selection can be efficient or inefficient depending on the information structure and mitigation mechanisms. The welfare loss is the wedge between the second-best outcome (under information asymmetry) and the first-best outcome (under symmetric information). In some settings (e.g., job-market signaling equilibria in Spence), the separating equilibrium is Pareto-inefficient but may be preferable to the collapse of the market that would occur under pooling.

**Not always the right diagnosis of market failure:**
Some apparent adverse-selection spirals can be explained by moral hazard (healthy people opt out because their use of insurance is low, not because they know their type is low-risk), by demand elasticity unrelated to hidden type, by transaction costs, or by network effects. Distinguishing adverse selection from alternatives is empirically subtle and requires identification strategies (exogenous premium variation, panel data on enrollment changes, field experiments) that are often unavailable.

**Not limited to market settings:**
Adverse selection appears in organ donation (those with worse organs more willing to donate), charity (those with higher preferences for giving self-select), nonprofit volunteering, dating and matching markets, employment (matching by unobserved productivity), and any setting where self-selection into participation depends on private information about type.

**Not fully fixed by information disclosure:**
Disclosure helps only if the disclosed information is credible, verifiable, and understandable to the uninformed side. In some cases, disclosure can paradoxically worsen outcomes (stigma from revealing type, crowding-out of implicit information, reputational damage that prevents future transactions).

Cross-references: see *moral_hazard* (the post-contractual information-asymmetry sibling — note the tight pairing); see *information_asymmetry* (the umbrella phenomenon); see *signaling* (informed-party mitigation); see *screening* (uninformed-party mitigation); see *agency_problem* (the broader principal-agent family); see *mechanism_design* (the formal framework for designing contracts under asymmetric information).

broad_use:
Adverse selection appears across at least eight high-consequence domains:

- **Insurance** (health, life, long-term-care, flood, annuities, disability) — the classical domain; unraveling in health insurance absent mandate motivated the Affordable Care Act's three-pronged architecture (individual mandate + subsidies + risk adjustment).
- **Credit markets** (credit-card and mortgage pricing, consumer and small-business lending, payday lending, equipment leasing) — credit rationing per Stiglitz-Weiss rather than price-clearing; adverse selection of borrower risk as interest rates rise.
- **Labor markets** (educational signaling, hiring credentials, job trial periods, apprenticeships) — workers with high productivity self-select into education and credentials to signal quality; separating equilibrium in Spence.
- **Used-goods markets** (cars, real estate, equipment, art, collectibles, wine) — lemons problem; mitigated by inspection, warranties, dealer reputation, third-party certification (Carfax, CarMax franchise-dealer guarantees).
- **Securities markets** (IPO pricing, underwriting, adverse selection against market makers, liquidity provision in high-volatility periods) — information asymmetry between insiders and outsiders.
- **Health-care policy** (mandated enrollment, community rating, guaranteed issue, risk-adjustment transfers) — adverse-selection spirals in individual health-insurance markets unless pooling is enforced.
- **Procurement and auctions** (winner's curse, adverse selection against the buyer in sealed-bid auctions, performance guarantees) — high-bidder types often realize only low-value objects.
- **Online marketplaces and platforms** (eBay, Airbnb, Uber, Fiverr, freelance platforms) — participant quality is hidden; reputation systems and reviews are mitigating signals.

clarity: Adverse selection clarifies why uniform pricing can fail when types are hidden, why healthy people not enrolling in insurance can cause premium spirals, why "lemons" drive out quality in used-goods markets, why credentials and warranties exist and are widespread (despite their seeming wastefulness in Spence), why screening menus in insurance and credit make sense (deductible-premium tradeoffs offering choice to different risk types), and why universal or mandatory participation can restore market function lost to selection. It provides a clean diagnosis for why a market collapses, thins, or requires heavy intervention — and it licenses specific policy responses (mandate, subsidy, risk adjustment, disclosure mandate, third-party certification, signaling/screening mechanism design).

manages_complexity: The construct manages the complexity of selection-driven market failures by reducing them to a canonical structure: hidden type + uniform terms + self-selection produces pool degradation. The mitigation logic (signaling, screening, mandates) then follows mechanically. Equilibrium concepts (separating, pooling, non-existence) organize the space of outcomes. Applied analysis identifies the relevant hidden type, the pooling mechanism, the equilibrium characterisation (is the market unraveling, stabilising at a separating equilibrium, or collapsing?), and the likely mitigation paths. The framework suppresses the massive variation in substantive context — insurance, credit, labor, goods — and exposes the common selection-dynamic structure underneath, enabling transfer of policy logic across domains.

abstract_reasoning:
Adverse-selection reasoning proceeds by:
(1) identifying the private type (health risk, productivity, credit risk, quality);
(2) specifying the market structure generating pooling (single price, premium, wage, interest rate applied to all types);
(3) characterising the willingness to participate as a function of type and contract terms;
(4) solving for the equilibrium pool composition (which types self-select into the transaction);
(5) asking whether the market unravels fully, partially (separating equilibrium with losses), or in a hybrid pooling-separating equilibrium;
(6) evaluating mitigation devices (signaling costs, screening menus, mandates, disclosure) for their efficiency and feasibility.

It licenses both theoretical predictions (equilibrium characterisation under asymmetry; predictions about premium spirals, credit rationing, market collapse) and applied policy analysis (design of insurance markets, credit systems, educational credentialing, platform-reputation systems). The reasoning is simultaneously mathematical (game-theoretic equilibrium under information asymmetry) and intuitive (self-selection of bad types is the core insight), making it a high-transfer abstraction across academic and policy audiences.

knowledge_transfer:
| Role | Insurance form | Lemons-goods form | Credit form | Labor form |
|---|---|---|---|---|
| Hidden type | Health / risk type | Quality of individual car | Creditworthiness / default probability | Productivity / ability |
| Pooling mechanism | Single community-rated premium | Single used-market price | Single interest rate | Single entry-level wage |
| Adverse consequence | Sick pool, rising premiums, unraveling | Lemons dominate, market thins / collapses | Bad borrowers, credit rationing | Low-productivity pool, credentials race |
| Mitigation | Medical underwriting, mandates, risk adjustment | Warranties, certifications, inspections | Credit scores, collateral, guarantors | Education signaling, trial periods |
| Classic reference | Rothschild-Stiglitz 1976[^rothschild-stiglitz-1976] <!-- FACT-D07-103 --> | Akerlof 1970[^akerlof-1970] <!-- FACT-D07-100 --> | Stiglitz-Weiss 1981[^stiglitz-weiss-1981] <!-- FACT-D07-104 --> | Spence 1973[^spence-1973] <!-- FACT-D07-101 --> |

An insurance economist's adverse-selection reasoning transfers to used-goods markets, credit markets, and labor markets with minimal notational change. The structural core is pre-contractual hidden characteristics inducing self-selection under uniform terms; what varies is the substrate and the mitigation device. The same equilibrium existence concerns (can a pure-strategy separating equilibrium exist, or only a pooling or hybrid equilibrium?) and efficiency questions (is the separating equilibrium second-best efficient?) apply across domains.

prose: *(Pass B — deferred.)*

notes:
Held at High confidence. Core information-economics construct. Entry pairs tightly with *moral_hazard* (#147); flagged conceptually rather than via tight_pair_with_X because the entries are separated by intervening drafts and the pairing is thematic (pre- vs post-contractual sibling) rather than mechanical. Fourth draft of batch DP-07 G2 (information-asymmetry tight cluster).

**Cross-DP linkage (DP-02 density pilot):** The Akerlof-Spence-Rothschild-Stiglitz citation backbone (akerlof-1970, spence-1973, spence-1974, rothschild-stiglitz-1976) is a heavy cross-DP candidate. Adverse-selection (#150 DP-07 G2) connects to signaling (#505 DP-01) and screening (#506 DP-01) via the same foundational citations — Spence 1973/1974 for signaling, Rothschild-Stiglitz 1976 for screening equilibrium in insurance. During B3 (cross-DP consolidation), verify whether these four citations are already populated in DP-01 signaling and DP-01 screening entries; if so, coordinate reference formatting and cross-cite to avoid duplication. Also check mechanism_design (#501 DP-01) for potential shared Rothschild-Stiglitz 1976 (screening is a mechanism-design tool). Mark: *Cross-DP B3 candidates: akerlof-1970, spence-1973, spence-1974, rothschild-stiglitz-1976 — verify dedup with DP-01 signaling (#505), screening (#506), mechanism_design (#501) at B3.*

**Cross-G2 linkage (DP-07 G2 information-asymmetry cluster):** Stiglitz-Weiss 1981 (credit rationing) is cited here in T3 context and in the Knowledge Transfer table as the credit-domain canonical reference. Also check *moral_hazard* (#147 DP-07 G2 same cluster, 20 drafts earlier) for whether stiglitz-weiss-1981 appears there (moral hazard in insurance and credit contexts often cites the same paper). If stiglitz-weiss-1981 is shared, coordinate and cross-cite. Mark: *Cross-G2 B3 candidate: stiglitz-weiss-1981 — verify shared usage in moral_hazard (#147) at B3.*

**Structural note:** The Akerlof, Spence, and Rothschild-Stiglitz papers form the canonical pre-contractual-information-asymmetry triumvirate (Nobel 2001). Wilson 1977 provides the equilibrium-refinement contribution that addresses the non-existence tension (T4). Einav-Finkelstein 2011 provides the empirical-identification breakthrough for separating adverse selection from moral hazard in insurance (relevant to T3). These five sources (akerlof-1970, spence-1973, rothschild-stiglitz-1976, wilson-1977, einav-finkelstein-2011) anchor all major theoretical and empirical advances in the field post-1970.

**Within-DP-07 neighbour notes:** *moral_hazard* (#147) is the post-contractual information-asymmetry sibling — once a contract is signed, the informed side (now the agent) can take hidden actions. *agency_problem* (#143) is the broader parent structure encompassing both pre-contractual selection and post-contractual moral hazard. *information_asymmetry* (#160) is the umbrella phenomenon covering both adverse selection (pre-contractual) and moral hazard (post-contractual). *signaling* (#505 DP-01) and *screening* (#506 DP-01) are the two main mitigation devices for adverse selection, located in DP-01 (prime abstractions — foundational structures). *mechanism_design* (#501 DP-01) is the formal framework for designing contracts and institutions under asymmetric information, of which signaling and screening are special cases.

**Related note (DP-02 scope):** The densification adds explicit 6-component Structural Signature (matching cardinality.md DP-02 template), converts all inline classical citations to footnote-marker form, expands Knowledge Transfer table footnote anchors, adds T4 refinement (Wilson 1977 anticipatory equilibrium), and populates Notes with cross-DP and cross-G2 linkages flagged for B3 consolidation pass.