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.

Background

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

Metaphysics

Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...

 as well as in the research on qualitative reasoning

Qualitative reasoning

Qualitative Reasoning is an area of research within Artificial Intelligence that automates reasoning about continuous aspects of the physical world, such as space, time, and quantity, for the purpose of problem solving and planning using qualitative rather than quantitative information...

, which makes building foundational ontologies an interdisciplinary task. 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.

Elements

The ontology identifies objects, attributes, and events as describing reality.

• 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; 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
• Attributes are properties and 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 that apply to more than one case, such as the formal universals of object, trope, parthood, dependence, and similarity
  • non-repeatables – 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
• 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.

Ontology

The ontology is organized by descriptions of the following:

• Parts and Wholes – involving mereology
  Mereology
  In philosophy and mathematical logic, mereology treats parts and the wholes they form...
  
  , the formal theory of parthood
• Similarity – involving repeatable and non-repeatable properties of objects and their attributes, and the intensity and comparability of those properties
• Dependence – involving the independence of objects and the dependence of attributes on the objects
• Connection, involving
  • topology
    Topology
    Topology is a major area of mathematics concerned with properties that are preserved under continuous deformations of objects, such as deformations that involve stretching, but no tearing or gluing...
    
     – the formal ontological theory of spatio-temporal connection
  • mereotopology
    Mereotopology
    In formal ontology, a branch of metaphysics, and in ontological computer science, mereotopology is a first-order theory, embodying mereological and topological concepts, of the relations among wholes, parts, parts of parts, and the boundaries between parts....
    
     – 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
  • thin and thick objects
• Inherence – involving the formal relation between thin and thick objects and their attributes to define direct parthood and essence
• Temporal Order – involving the principle of succession, events (changes or state-transitions), endurants (thick objects) and perdurants (processes, or successions of thick objects); events are sums of two directly succeeding thick objects, while processes are arbitrary sums of events; 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.

See also

• Causal chain
  Causal chain
  In philosophy, a causal chain is an ordered sequence of events in which any one event in the chain causes the next. Some philosophers believe causation relates facts, not events, in which case the meaning is adjusted accordingly.-See also:*Causality*Event...
  
  
• Commonsense knowledge
• Event segment
• Formal Ontology
  Formal ontology
  In philosophy, the term formal ontology is used to refer to an ontology defined by axioms in a formal language with the goal to provide an unbiased view on reality, which can help the modeler of domain- or application-specific ontologies to avoid possibly erroneous ontological assumptions...
  
  
• Process ontology
  Process ontology
  In computer science, a process ontology is a description of the components and their relationships that make up a process. A formal process ontology is an ontology in the knowledge domain of processes. Often such ontologies take advantage of the benefits of an upper ontology...
  
  
• Sequence of events
• Upper ontology
• World line
  World line
  In physics, the world line of an object is the unique path of that object as it travels through 4-dimensional spacetime. The concept of "world line" is distinguished from the concept of "orbit" or "trajectory" by the time dimension, and typically encompasses a large area of spacetime wherein...