Approaching What-, How- and Why-Questions Using a Medical Example - Fuzziness and Medicine - page 242

Fig. 17.4 Graph example to answer What causes lung cancer?

To compose an answer, we just have to gather the nodes and relationships point-
ing at the lung cancer node, e.g., in this case, smoking , radon gas and tobacco use.
The algorithm with this information performs the answer displayed in figure 17.5.
A simple interface, using Php and HTML languages, translates the graph into text:

Fig. 17.5 Automated answer to the question What causes lung cancer?

17.3 Answering How-Questions

To address how-questions , the first step it to locate the causal paths connecting the
concepts involved in the question. How-questions usually involve two concepts in
the same question, the concept 'cause' and the concept 'effect'. Thus, if we ask
How X causes Y? , the objective is to find the causal path connecting X (as head of
this path) to Y . Once the 'cause' concept has been located in the database (it will
appear in the Relationship table as cause_concept), a recursive algorithm finds the
possible paths connecting the concept cause with the concept effect. The main steps
of it are the following: