Object-centered high-level reference ontology

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The Object-Centered High-level REference ontology (OCHRE) is an upper ontology (top-level ontology, or foundation ontology), a formal ontological framework whose purpose is to describe very general concepts that are the same across all knowledge domains.[1]


OCHRE was developed by Luc Schneider at the Institute for Formal Ontology and Medical Information Science at the University of Leipzig. This ontology was developed not only to create a particular basic ontological framework, but also to demonstrate how the quality of a foundational ontology depends on descriptive adequacy and on formal simplicity and transparency. The design choices for top-level ontologies are the same as the ontological choices discussed in the branch of philosophy metaphysics as well as in the research on qualitative reasoning, which makes building foundational ontologies an interdisciplinary task.[1](pp1–2) OCHRE has a focus on conceptual simplicity, so that the number of basic (primitive) concepts and relations is as small as possible in order to simplify the theory, but the relatively small number of items in the representation means that more work is required when translating to other forms or uses.[2]


The ontology identifies objects, attributes, and events as describing reality.[1](p4)

  • Objects are bundles of attributes that have qualities of completeness and independence. Examples are quarks, tables, stones, companies, and solar systems. Objects are distinguished in the ontology as:
    • thin objects – having a core of enduring characteristics, or sums of essential tropes, which are properties that the thin objects possess during their whole lives;[2] this corresponds to the endurants/objects of DOLCE
    • thick objects - having spatio-temporal bulk that undergo change, and being stages or phases or shapshots of thin objects; having sums of tropes that thin objects possess at a certain time[2]
  • Attributes are properties and semantic relations. Examples are the various shades of color on a soap bubble, the mass and velocity of a bullet, a person's intelligence, and a person's relationship with their parents. Attributes may be regarded as:
    • repeatables (universals) – these apply to more than one case, such as the formal universals of object, trope, parthood, dependence, and similarity
    • non-repeatables (particulars) – these are property-instances or tropes that are single characteristics of individuals; these properties are the atoms of the ontology, the simpler entities of which all other entities are composed[2]
  • Events are changes or state-transitions. Examples are runnings, hugs, bank transfers, perceptions, and thinkings. Events are accounted for in the ontology as a succession of object stages or phases.


The ontology is organized by descriptions of the following:

  • Parts and Wholes – involving mereology, the formal theory of parthood[1](pp2–3)
  • Similarity – involving repeatable and non-repeatable properties of objects and their attributes, and the intensity and comparability of those properties[1](pp4–5)
  • Dependence – involving the independence of objects and the dependence of attributes on the objects[1](p6)
  • Connection, involving[1](pp7–8)
    • topology – the formal ontological theory of spatio-temporal connection
    • mereotopology – the topological constraints of mereology
    • change – the succession of temporary aggregations of attributes, or the succession of thick objects (snapshots) relative to the same thin object[2]
    • thin and thick objects
  • Inherence – involving the formal relation between thin and thick objects and their attributes to define direct parthood and essence[1](pp9–10)
  • Temporal Order – involving the principle of succession, events (changes or state-transitions), endurants (thick objects) and perdurants (processes, or successions of thick objects);[1](pp11–12) events are sums of two directly succeeding thick objects, while processes are arbitrary sums of events;[2] these events and processes roughly correspond to the perdurants/events of DOLCE

There are no spatial and temporal entities in the ontology, only spatial and temporal relations on thick objects.[2]

See also[edit]


  1. ^ a b c d e f g h i Luc Schneider (2003). "How to Build a Foundational Ontology: The Object-Centered High-level Reference Ontology OCHRE" (PDF). University of Leipzig: Institute for Formal Ontology and Medical Information Science. 
  2. ^ a b c d e f g "Foundational Ontologies & Their Library" (PDF). Institute of Cognitive Science and Technology: Laboratory for Applied Ontology (LOA). 2005. pp. 32–34.