 Diagnosis is the process through which a clinician determines what is wrong with a patient who is ill or ailing in some way. Although a critical part of the practice of medicine, it has been relatively neglected in the literature of philosophy of medicine particularly in comparison to more statistically-based methods for evaluating evidence in other fields (Stanley and Campos 2013). The key philosophical issues that arise in this context relate to how such determinations can be made in a manner that is accurate given the high amount of uncertainty and complexity often associated with the human condition, and hence involve logical, epistemological, and ontological issues. The usual way of proceeding in a clinical setting is to ask the patient to articulate what is ailing him or her, and thus to use a standardized reporting format to detail various symptoms which represent subjective manifestations of the illness or disease. In addition, clinicians perform various tests and examinations that allow more objective manifestations or signs to be recorded, such as heart rate, blood pressure and count, reflexes, and so on. A perennial debate in the philosophy of medicine is what constitutes symptoms and signs and whether they are in fact distinct, which relates to deeper issues about the realism of disease conditions as discussed above  (Section 2).