Unknowable Boundary: Fixing "Unknowability" to Establish Responsibility

1. Introduction: Why Responsibility Always Evaporates in AI Accidents and Business Failures

"Why is it that in AI accidents or major business troubles, after all the exhaustive explanations, we end up in a state where no one can truly be held accountable—the 'Evaporation of Responsibility'?"

The reason lies in the timing of our "explanations." Most organizations work desperately to construct explanations after a problem occurs. However, the conclusion is clear: Responsibility is not born from post-hoc explanations.

Unless you fix the "blank space" of what is not known at the exact moment a decision is made, responsibility cannot exist. We call this fixed limit the "Unknowable Boundary."

2. Definition: Fixing the "Unknowable," Not Just the "Unknown"

Definition of Unknowable Boundary: The limit established before a decision is made, identifying what is fundamentally impossible to fill with the information available at that time.

It is crucial to distinguish between "Unknown" and "Unknowable":

• Unknown: Something we don't know now, but can understand later (e.g., by adding more data).

• Unknowable: A void that cannot be filled by any means at the moment the decision is executed.

The Unknowable Boundary is a "Unit of Record," Not a "Declaration": The Unknowable Boundary is not established simply by "saying" it. A decision involving a boundary (X) only becomes valid the moment the known facts (Inside: A–C) and the void (Boundary: X) are fixed together as a single immutable log. Responsibility is the manifestation of the will to accept this fixed record.

Crucial Note: X is not an exemption from liability. The act of deciding not to fill X is the very essence of the responsibility being taken. This rigorous fact is the core of the Unknowable Boundary.

3. The "Evaporation of Responsibility": How Post-hoc Explanations Kill Accountability

Why does responsibility vanish the more we "explain"?

• Phenomenon: After an accident, explanations proliferate as part of the cause analysis, eventually leading to the conclusion that it was "unavoidable."

• Structure: Because no boundary (Unknowable range) was drawn and fixed as a record beforehand, the boundary can be conveniently rewritten after the fact (the intrusion of the "Ghost"). This allows for post-hoc justifications, claiming it was either "predictable" or an "act of God."

The Core Principle: Responsibility cannot exist in a decision where an Unknowable Boundary was not established in advance. Decisions without this fixation allow for the infinite rewriting of justifications, leading to the fundamental collapse of accountability.

4. Three Common Misconceptions

1. It is not about "solving it with more data." Even with more data, the "margin of interpretation" (the void) at the moment of judgment does not disappear.

2. It is not about "covering it with probability." Saying "there is a 90% success rate" is often used as a pretext to abandon responsibility when the remaining 10% occurs.

3. It is not "Accountability = Explaining things well." True accountability is not about speaking fluently after the fact; it is about determining—and recording—what will not be explained beforehand.

The Unknowable Boundary is not a "communication technique"; it is a "precondition" for decision-making.

5. Practical Check: Is the "Unknowable Boundary" Established?

Ask these four questions to determine if the boundary for establishing responsibility exists in your current decision:

• Q1. Is that "unknowability" the kind that disappears by adding data?

  • YES → It is a mere "Unknown."

  • NO → Proceed to Q2.

• Q2. If you fill that void before the decision, will it allow the explanation to be rewritten later?

  • YES → That is exactly where the "Unknowable Boundary" must be drawn.

• Q3. Is the resolve of "if it deviates, it can't be helped" placed before the decision, rather than after?

  • YES → The boundary is established.

  • NO → The boundary is not established.

• Q4. Are the internal facts (A–C) and the boundary (X) recorded in a tamper-proof manner?

  • YES → You are ready for responsibility to be established.

  • NO → It is still just a "declaration," and the boundary does not yet truly exist.

6. Concrete Example: "Sealing the Decision" in AI Deployment

Consider the decision to deploy an AI model:

1. Inside (Certain Facts): Distribution of training data, test accuracy, current parameters, and Adoption Criteria (the specific threshold used to justify deployment).

2. Boundary (Unknowable Void): Unknown input patterns in the production environment.

3. Fixing: Log the statement "Behavioral response to unknown inputs in production is unpredictable" before the decision is made.

Deploying without fixing this boundary leads to an infinite proliferation of excuses like "it was unexpected," "poor operation," or "biased data" after an accident, effectively rewriting the decision itself. Boundary fixation is the "Sealing of Decision-making" that physically (immutably) prohibits this post-hoc rewriting.

7. "Ghost" vs. "Boundary": A Line vs. Erosion

• Unknowable Boundary: A clear "limit" fixed at the moment of judgment.

• Ghost: The post-hoc intrusion of meaning and excuses that act as if that limit never existed, "trampling over the line."

By sealing the Unknowable Boundary as a record, you preemptively block the gaps where Ghosts emerge.

8. Triggers of Evaporation: Phrase Collection of "Filling the Void"

When the following phrases appear after the fact, the Unknowable Boundary was not fixed in advance, and responsibility has evaporated:

• "It was reasonable at the time."

• "It was unexpected (unforeseen)."

• "We made a comprehensive judgment."

• "We worked on a best-effort basis."

• "Hindsight is 20/20, but..."

• "It would have been different if we had the data."

• "It was appropriate from a probabilistic standpoint."

When these words appear, you are not looking at a boundary, but at a post-hoc rewrite (Ghost).

9. The Three Benefits of the Unknowable Boundary

1. Stopping the Proliferation of Excuses: Because you fixed "what is not known" in advance, post-hoc excuses are blocked.

2. Defining the Scope of Responsibility: The scope of "what is being taken responsibility for" is synchronized at the moment of the decision.

3. Reproducibility of Improvement: Because the "Inside (Known)" facts are recorded, verification under the same conditions becomes possible.

10. Connection to Implementation: Systematizing Responsibility

The Unknowable Boundary is the starting point for establishing the following logical framework in practice:

• Finite Closure: Closing the infinite proliferation (Ghostification) of explanations and conditions.

• Post-hoc Impossibility: Physically and institutionally prohibiting the redrawing of boundaries after an accident.

• ADIC/$\Sigma1$**: Treating only the "fixed logs" inside the boundary as valid evidence.

11. Practical Format: Minimum Template for Unknowable Boundary

Use this template to "seal" your decision and establish responsibility in practice.

Item	Content
Inside (Fixed Facts)	A, B, C ... (Current data, premises, logic, Adoption Criteria/Thresholds)
Boundary (Unknowable Void)	X (e.g., Unknown environmental factors, user behavior)
Prohibitions (Forbidden Post-hoc Explanations)	Do not use "Unexpected" or "Reasonable at the time" to fill X.
Acceptance (Handling Deviations)	Accept deviations as originating from X; no excuses other than deficiencies in A–C. Accept responsibility for the decision to select X itself.
Record (Physical Evidence)	Inputs, premises, outputs, timestamp, signatory (Hashed/Immutable log storage).

12. Conclusion: Responsibility Cannot Be Created After the Fact

Responsibility is not about providing a perfect explanation. Rather, it is about fixing and recording the boundary of "what cannot be explained" earlier than anyone else, before the decision is made.

Only when the Unknowable Boundary is fixed as a "unit of record" can we truly take responsibility.