Vol.:(0123456789) 1 3 Topoi DOI 10.1007/s11245-017-9516-2 The Logic of Medical Diagnosis: Generating and Selecting Hypotheses Donald E. Stanley 1   © Springer Science+Business Media B.V. 2017 and summary, i.e. it is diagnostic conjectures, testing, rejection, review, and summary, i.e. it is an iterative pro- cess. It can then be said that diagnostic hypotheses are also ‘observation-laden’ (Black et al. 1999; Wulf and Gøtzsche 2000). In abductive methodology, theory-ladenness and ‘observation-ladenness’ are reciprocating agents; one makes judgments based on experience and training while the lat- ter is enabled by skills of observation; both are operative in dynamic processes of inquiry. In this paper, I want to pro- vide experiential insight into the method of this diagnostic process. My aim is to enlarge on the strategies of medical diagno- sis as it is meshed into training and clinical experience—that is, to describe the patterns of reasoning used by experienced clinicians under diferent diagnostic circumstances and how these patterns of inquiry allow further insight into the evalu- ation and treatment of patients. I do not aim to present a theory and illustrate it with examples; I wish rather to let a realistic example, similar to actual clinical scenarios, direct the exposition. To this end, I introduce an account of medi- cal diagnosis—briefy comparing and contrasting it to other accounts—in order to focus on discussing the process of diagnosis through a detailed clinical case. 2 The Logic of Medical Diagnosis The process of medical diagnosis involves three phases. These are interrelated reasoning processes, but they can be distinguished (Sehon and Stanley 2003): 1. Hypothesis-generation, based predominantly on sensory input (see Figs. 1, 2): patient-history, physical examina- tion, testing. The key to diagnostic judgment is based on continuing further examination. In a sense described Abstract Clinical diagnostic medicine is an experimental science based on observation, hypothesis making, and test- ing. It is an use dynamic process that involves observation and summary, diagnostic conjectures, testing, review, obser- vation and summary, new or revised conjectures, i.e. it is an iterative process. It can then be said that diagnostic hypoth- eses are also ‘observation-laden’. My aim is to enlarge on the strategies of medical diagnosis as these are meshed in train- ing and clinical experience—that is, to describe the patterns of reasoning used by experienced clinicians under diferent diagnostic circumstances and how these patterns of inquiry allow further insight into the evaluation and treatment of patients. I do not aim to present a theory and illustrate it with examples; I wish rather am to let a realistic example, similar to actual clinical scenarios, direct the exposition. To this end, I introduce an account of medical diagnosis—briefy comparing and contrasting it to other accounts—in order to focus on discussing the process of diagnosis through a detailed clinical case. Keywords Pragmatics · Diagnosis · Decision-making · Bayesian · Observation 1 Introduction Clinical diagnostic medicine is an experimental science based on observation, hypothesis generation, and testing. It is an on-going dynamic process that involves observation * Donald E. Stanley stanld@mmc.org 1 Department of Pathology, Maine Medical Center, Portland, ME, USA