Off the Edge of the Map

2025-11-17 · Source: The Ontologist · Field: Technology & Digital — Artificial Intelligence & Machine Learning, Data Science & Analytics · Depth: Advanced, medium

Summary

Off the Edge of the Map" analyzes Jessica Talisman's critique of the "closed-world assumption" (CWA) in knowledge systems, contrasting it with the open-world assumption (OWA) inherent to ontologies. Talisman argues against treating unstated facts as false. The article extends this, showing how SPARQL queries, especially those using negation-as-failure constructs like "!BOUND(?endDate)", and SHACL validation implicitly adopt CWA. It introduces the Holon Graph Architecture as a solution, where closure is explicitly declared via SHACL shapes as a "boundary," defining a map's scope. This architecture differentiates between a holon's internal "boundary" and external "portals" for federated data, preventing silent boundary expansion during SERVICE calls. A holonic system emits an "expansion request" for missing data, distinct from a "boundary violation," ensuring "I don't know" is not mistaken for "no."

Key takeaway

For AI Architects designing knowledge graphs, understanding the distinction between open-world and closed-world assumptions is critical. Implicitly relying on negation-as-failure in SPARQL or SHACL can lead to systems that generate false conclusions from missing data. You should explicitly define data boundaries using architectures like the Holon Graph Architecture, which clearly separates internal scope from external data access. This ensures your system can accurately signal "I don't know" instead of incorrectly asserting "no" when data is merely absent.

Key insights

Conflating absence of data with negative claims (CWA) in open-world systems leads to false conclusions.

Principles

• Absence of a claim is not a negative claim.
• Negation-as-failure constructs imply a closed-world assumption.
• Explicitly declared boundaries prevent implicit closure assumptions.

Method

The Holon Graph Architecture uses SHACL shapes to declare explicit boundaries for holons, distinguishing internal validity from external data access via portals.

In practice

• SPARQL queries with "!BOUND()" or "NOT EXISTS" make CWA moves.
• SHACL validation rules like "sh:minCount" or "sh:closed" operate under CWA.

Topics

• Knowledge Graphs
• Ontologies
• Closed-World Assumption
• Open-World Assumption
• SPARQL
• SHACL
• Holon Graph Architecture

Best for: Research Scientist, AI Scientist, AI Architect, Data Scientist

Related on AIssential

• The Open World/Closed World Conundrum — The semantic web is shifting from Open World to Closed World Assumptions, driven by practical system demands.
• Holons, Boundaries, and Context Graphs: From Koestler to SHACL — Holons, entities simultaneously whole and part, offer a robust framework for structuring complex knowledge systems.
• Semantic Foundations for Reliable Enterprise AI — Semantic clarity in data, achieved through robust data contracts and ontologies, is crucial for reliable enterprise AI outputs.
• Provenance-Enhanced Statements in Knowledge Graphs — DEC interprets knowledge graph provenance as epistemic stance, enabling principled reasoning over attributed claims and disagreements without collapsing into inconsistencies.
• Abstractions of Queries in Ontology-Based Data Access — The paper extends UCQs to express complete query abstractions in OBDA without increasing complexity.
• Not an Ontology — Major data platforms market "ontologies" that lack true reasoning and inference, failing to meet core definitional requirements.

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Editorial summary, takeaway, and curation by AIssential. Original article published by The Ontologist.