 The tricky part of the process is to find a means for mapping these symptoms and signs onto a particular disease condition. Some would advocate that this process is no different than usual methods in philosophy of science for hypothesis generation and testing based on evidence, and this type of model fits with what is termed differential diagnosis. Differential diagnosis involves a set of hypothetical explanations for a particular condition which come to be ruled in (or out) based on the evidence together with additional data that is collected, hence relying on a form of reasoning via decision nodes or algorithmic pathways (Stanley and Campos 2013). However, the details of the rules of reasoning that underlie this sort of process remain largely unarticulated, as does the amount of “tacit” knowledge that may contribute to diagnostic reasoning.