Ontological commitment

(PD) Image: John R. Brews
The ideas of a conceptualization are crystallized in a language expressing the conceptualization, leading to one or more ontologies. For each ontology, some of its entities with some of their relationships form that ontology's 'ontological commitment'.

The term ontological commitment is used as a general term in both philosophy and in information systems to refer to the essential elements of an ontology. Quine proposed that given some theory its ontological commitment could be found by what might be called a translation via techniques of symbolic logic and a search through this translation for statements involving there exists at least one ‘such-and-such’. Such statements are called quantifier expressions and the formulation ‘there exists’ in symbolic logic is represented by the 'turned E' or ∃. A list of the ‘such-and-such’ can then be examined to determine subsets that can serve as minimal sets in terms of which the others can be defined, and any such minimal set is an ontological commitment of the theory. This approach appears to involve only a list of ‘such-and-such’, but of course finding a minimal set of ‘such-and-such’ also involves at least some of the relations specified to hold between them.

The need to discuss and compare ontologies leads to the idea of a 'conceptualization', a higher level abstraction for which a given ontology is a very particular realization, possibly only one of many realizations of the 'conceptualization'. Each ontology based upon the same overarching conceptualization is then thought of as engendering a particular 'ontological commitment' that maps the conceptualization into specific examples of ‘such-and-such’ and their relationships. The 'conceptualization' allows discussion of its various possible implementations. The question then arises as to how to describe the 'conceptualization' in terms that can encompass multiple 'ontological commitments'. This issue has been called the 'Tower of Babel' problem, that is, how can persons used to one ontology talk with others using a different ontology? This problem is easily understood, but a general resolution is not at hand. It can be a 'bottom-up' or a 'top-down' approach, or something in between.

An example of the problems encountered in comparing ontologies is found in translation between human languages. Ostensibly, as all humans live in the same world and have the same physical senses with which to see the world, one might expect to correlate human activity with language and thereby make rules for translation. However, that view is utopian because humans act upon cultural interpretation of their surroundings, and relating two cultures is an entirely different matter than understanding what term in both represents a 'rabbit'. Some suggest that humans think in 'mentalese', but so far we don't have access to this level of conceptualization.

However, in more artificial situations, such as information systems, the idea of a 'conceptualization' and 'ontological commitment' to various ontologies that realize the 'conceptualization' is possible. A trivial example of moving conception into a language leading to a variety of ontologies is the expression of a process in pseudocode (a strictly structured form of ordinary language) leading to implementation in several different formal computer languages like Lisp or Fortran. The pseudocode makes it easier to understand the instructions and compare implementations, but the formal languages make possible the compilation of the ideas as computer instructions.

Another example is mathematics, where a very general formulation (the analog of a conceptualization) is illustrated with 'applications' that are more specialized examples. For instance, aspects of a function space can be illustrated using a vector space or a topological space that introduce interpretations of the 'elements' of the conceptualization and additional relationships between them but preserve the connections required in the function space.