About & method
Generation
The ontology was produced by BFO-Agent, an automated pipeline that reads a source text and expresses its concepts as OWL classes grounded in the Basic Formal Ontology. Each ICD-11 category is typed under a BFO leaf — commonly a disposition (a disease as a realizable tendency of a bearer), a process (an infection, an inflammation), or a material entity (an anatomical structure or a pathogen) — and related to others through Basic Formal Ontology and Relation Ontology relations such as part of, has participant, occurs in, and realized in. The artifact imports BFO and was reasoned over with HermiT.
Consistency is not coherence
Two distinct properties are easy to conflate. Consistency asks whether any logical model of the ontology exists at all; this ontology is consistent. Coherence asks whether every named class can have instances; this ontology is not coherent, because 87 named classes are equivalent to owl:Nothing. A consistent-but-incoherent ontology is one that hangs together globally yet contains individual classes that can never be populated. The viewer marks every such class with ⊥.
The failure mode behind the 87
The unsatisfiable classes are translation artifacts of this draft extraction, not defects in ICD-11. The dominant cause is a recurring modeling slip: a realizable entity — a role or a disposition — is attached to a class as if the class were its bearer. In the Basic Formal Ontology a specifically dependent continuant cannot be the bearer of another, and a bearer relation carries a declared range, so the assertion forces a class (or its filler) under two disjoint BFO categories at once and the reasoner collapses it to nothing.
The affected classes make the point on their own. A vitamin, a bacterial species, and a cell organelle are among those that collapse — entities no reading of ICD-11 would call logically impossible. Their unsatisfiability lives in the translation, not in the source.
The unsatisfiable classes fall into a few cascades rather than 87 independent problems. Most descend from a small number of roots — an autoimmune cluster, a streptococcal and rheumatic chain, a myocarditis chain, an ocular chain, and a handful of isolated collapses — so repairing the roots heals the dependents. The Coherence view in the browser groups them this way. The defect is systematic across extractions and is being fixed at the level of the pipeline's anti-pattern rules and validation gate rather than by hand, per artifact.
How to read the browser
The BFO Tree groups classes under their Basic Formal Ontology category and lets you descend the ICD-11 subclass hierarchy. Search matches labels, identifiers, and definitions across the whole ontology. Coherence lists the 87 unsatisfiable classes by cascade. Selecting any class shows its BFO anchor, definition, superclasses and subclasses (each clickable), and its OWL restrictions rendered in readable form; unsatisfiable classes carry a note explaining the collapse.
Provenance & licence
ICD-11 is a product of the World Health Organization. This independent formal rendering was generated and validated with BFO-Agent (github.com/dkoepsell/bfo-agent) and is released under CC-BY 4.0. It is a research artifact, not a clinical instrument.