Physicians are engaged in incorporating quantitative methods for making clinical decisions into their practices. An acquaintance with semiotics, the doctrine of signs, may complement this project. A sign stands for something. We communicate indirectly through signs, and by interpreting what signs mean we make sense of our world and diagnose and understand our patients. Thus, through association and inference, we transform flowers into love, Othello into jealousy, and staring eyes into thyrotoxicosis.
Characteristically in diagnosis, beginning with an unstable inference, we test and otherwise ask questions likely to produce signs that support (or discredit) our hypothesis. In a literary sense, we join with the author to clarify and rewrite the text; creative interpretation is the key. Diagnosis is concluded through narration, by the meaning that is revealed by telling the story of the patient.
Diagnosis will succeed only to the extent that we respect the principles and caveats of sign interpretation. The sign is both the key to the unknown and the master impersonator. The sign and its meaning are usually not the same; meaning has to be inferred. Because interpretations are made subjectively, they are circumscribed by the experience and bias of the clinician. Moreover, the contexts in which the sign appears shape the meaning of the sign and may change it altogether.