Knowledge needed for expert system explanation

Adequate explanations of the steps followed by an expert system can sometimes be produced automatically by paraphrasing the rules or methods of the system in English. However, this approach will not work for other kinds of explanations, such as justifications of the system's actions. The problem is that the basis for justifications lies in knowledge used to create the expert system, which is not represented in the system's code and hence is unavailable for explanation. This paper outlines an approach to capturing the knowledge required to provide justifications and illustrates both the problem and the solution with examples of machine-generated English text.