ISO/IEC 21838-2:2021

INTERNATIONAL ISO/IEC
STANDARD 21838-2
First edition
2021-11
Information technology — Top-level
ontologies (TLO) —
Part 2:
Basic Formal Ontology (BFO)
Technologies de l'information — Ontologies de haut-niveau (TLO) —
Partie 2: Ontologie formelle de base (BFO)
Reference number
© ISO/IEC 2021
© ISO/IEC 2021
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© ISO/IEC 2021 – All rights reserved

Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Conformity of BFO-2020 to ISO/IEC 21838-1 . 3
4.1 Overview . 3
4.2 Natural language representation of BFO-2020 . 3
4.3 OWL 2 formalization of BFO-2020 . 3
4.4 Common Logic axiomatization of BFO-2020 . 3
4.4.1 General . 3
4.4.2 Modularity . 4
4.5 Specification of the purpose of BFO (in conformance with ISO/IEC 21838-1:2021,
4.4.2) . 4
4.5.1 General . 4
4.5.2 Example Open Biomedical Ontologies (OBO) . 4
4.5.3 Example Common Core Ontologies (CCO) . 4
4.6 Description of how conformance of a domain ontology to BFO is established (in
conformance with ISO/IEC 21838-1:2021, 4.4.3). 5
4.6.1 Overview . 5
4.6.2 Conformance through direct extension. 5
4.6.3 Conformance through indirect extension. 6
4.6.4 Conformance through re-engineering . 6
4.6.5 Validating conformance to BFO . 6
4.7 Specification of how consistency of the CL axiomatization of BFO-2020 is
demonstrated (in conformance with ISO/IEC 21838-1:2021, 4.4.4) . 6
4.7.1 Overview . 6
4.7.2 Documentation. 7
4.7.3 Structure of the model . 7
4.8 Description of how interpretability of the OWL 2 axiomatization of BFO-2020 in
the CL axiomatization is established (in conformance with ISO/IEC 21838-1:2021,
4.4.5) . 7
4.8.1 Interpretability proof strategy for BFO-2020-OWL . 7
4.8.2 Interpretability for alternative axiomatizations of BFO-2020 . 8
4.9 Demonstration of breadth of coverage of BFO (in conformance with with ISO/IEC
21838-1:2021, 4.4.6) . 9
4.9.1 General . 9
4.9.2 Space and time . . 9
4.9.3 Actuality and possibility . 9
4.9.4 Classes and types . 9
4.9.5 Change over time . 9
4.9.6 Parts, wholes, unity and boundaries . 10
4.9.7 Space and place . 10
4.9.8 Scale and granularity . 10
4.9.9 Qualities and other attributes . 10
4.9.10 Quantities and mathematical entities . 10
4.9.11 Processes and events . 11
4.9.12 Constitution . 11
4.9.13 Causality . 11
4.9.14 Information and reference. 11
4.9.15 Artefacts and socially constructed entities . 11
4.9.16 Mental entities; imagined entities; fiction; mythology; religion .12
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© ISO/IEC 2021 – All rights reserved

4.10 Documentation of ontology management principles (in conformance with ISO/
IEC 21838-1:2021, 4.4.8) .12
Bibliography .13
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Foreword
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Attention is drawn to the possibility that some of the elements of this document may be the subject
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This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 32, Data management and interchange.
A list of all parts in the ISO/IEC 21838 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
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Introduction
Basic Formal Ontology (BFO) is a top-level ontology (TLO) conforming to ISO/IEC 21838-1. It contains
(i) definitions of its terms and relational expressions and (ii) formalizations in OWL 2 and in Common
Logic (CL). BFO is a public-domain resource introduced in 2002. It is an ontology of highly general terms
designed to support the interoperability of data and information systems associated with ontologies
containing more specific terms relating to specific domains. The primary goal of BFO is to support
the development of such domain ontologies in a way that promotes the coordination of ontology
development by different groups in a way that promotes consistency and non-redundancy. BFO was
initially conceived as part of a strategy to advance coordinated domain ontology development across
the life sciences. BFO has since been used for similar purposes in other areas, including data and
information science, sustainable development, and in the engineering, military and intelligence fields.
This document was developed as a response to the need for a TLO designed to support information
system interoperability expressed by ontology users in these and other areas.
BFO is a domain-neutral ontology. This means that it provides terms representing only highly general
categories – such as object, quality, process, spatial and temporal region – which pertain to all domains
of reality.
BFO has existed thus far in four major release versions.
Version 1.0 (released in 2002)
Version 1.1 (released in 2007)
[7]
Version 2.0 (released in 2015)
[10] [11]
Version 2020 (released in 2020) ,
Through these successive versions the categorial core of BFO, resting on a distinction between
continuants and occurrents, and between dependent and in
...