Jeremy R. Simon’s article, “Constructive Realism and Medicine: an approach to medical ontology”, provides an opening for potential future understandings of evolving singular-model accounts. This was not the primary focus of his article, but the concept of multiple-models/diseases is an interesting talking point. There is a correlation between the number of models and number of diseases – one model per disease. Simon discards the notion of multiple models per disease, and suggests that one model determines and simultaneously accommodates our understanding of the corresponding disease. Only when new tests are available do we arrive at multiple models, but these models only correspond with multiple diseases – it’s still the one model per disease scenario.
But it’s precisely these new tests that allow for evolving singular model accounts. For example, genetic tests can determine the presence of KRas mutation or wild-type (“normal”) KRas gene. This is significant because only certain epidermal growth factor receptor (EGFR) inhibitors manipulate wild-type KRas colorectal cancers. The same EGFR inhibitors are ineffective against the KRas mutation. One way of looking at this suggests that, as a result of the test, there are two models (wild-type KRas or KRas mutation) and two corresponding diseases (conditions represented by colorectal cancer +/- the wild-type KRas model). Another way of looking at this suggests that these two models (wild-type KRas or KRas mutation) evolved from a singular model (colorectal cancer). And when it is considered that the only significance of the +/- wild-type KRas mutation is that fact that an EGFR inhibitor may or may not be effective, the KRas models are seen as specialized.