Ontology use in the context of this research is beneficial in that it allows knowledge sharing and re-use. Although reuse may not be a challenge in this research as we will be modeling our ontology from scratch, it is important to ensure consistency. Without consistency, extendability of our ontology may be compromised; in a sense that it may be difficult to reuse.

Some important questions related to reuse include:

• How the changes will be handled.
• How versions of the ontologies will be related.
• How to store ontologies.
• How to identify and retrieve ontologies.

Central to these questions is the problem of harmonising the concept descriptions. For example, consider building a taxonomy that will be used to capture the statement” ‘HIV/Aids is an infectious disease that is not curable‘. With this in mind, which of these two is more preferable?

Right now I cannot say which between the two is better, but if at all one is better then it means there are good and bad ontologies. This is something to explore (but certtainly not today)! The point for today is simply to suggest that the two demonstrate that the challenge lies largely with the conceptualisation of the intial model; since to maintain consistency one depends mostly on initial modelling decisions. Further, idea of re-use of an ontology cannot be taken for granted even though it is one of the most cited reason for using ontologies.