The Logic of Diagnosis: Peirce, Literary Narrative, and the History of Present Illness

Abstract

This essay presents a theoretical construct upon which to base a working--"pragmatic"--definition of the History of Present Illness (HPI). The major thesis of this essay is that analysis of both the logic of hypothesis formation and literary narrative--especially detective stories--facilitates understanding of the diagnostic process. The essay examines three elements necessary to a successful development of a patient's HPI: the logic of hypothesis formation, based upon the work of the philosopher-logician, Charles Sanders Peirce; the organization of knowledge in relation to structures of narrative; and the feedback necessary to the successful physician-interviewer. It concludes with a systematic description of the design of hypothesis formation within diagnoses.

Logic Structure of Clinical Judgment and Its Relation to Medical and Psychiatric Semiology

“…As Schleifer and Vannatta [14] as well as Fischer [13] and Feinstein [5] state, hypothesis in clinical judgment runs from the effect (speckles, chest pain, unexplained abnormal behavior or experience, insomnia) to putative causes (measles, angor pectoris, schizophrenia). In classical logic, this would be an example of fallacious reasoning called fallacia consequentis , but this is the very feature called ‘retroduction’ by Peirce [[16], 5.276, 6.479].…”

“…Schleifer and Vannatta [14] have proposed three elements as constituent to the epistemic core of clinical judgment: first, some ‘knowledge base’, which comprises the current body of empirical knowledge about symptoms and disorders. It also includes descriptive definitions of signs and symptoms, either operationalized or not, demographic data concerning syndromes and pertinent laboratory or neuroimaging results [5].…”

“…Early contemporaneous work on the subject considered clinical judgment an inductive, deductive or Bayesian inference [8,9,10] and even proposed for it a structure similar to that of laboratory experiments [1]. However, it was also noted that some constraints which bound clinical judgment did not easily fit these models [11,12,13,14]: clinical judgment deals with single particulars for which some category must be found (induction infers a general rule out of several particulars and deduction needs the rule in advance). It must balance general knowledge about diseases and its presentations with specific features of the case.…”

“…It follows a ‘known-effect-to-putative-cause’ reasoning direction, with different possibilities of interpretation of the empirical fact. Thus, a number of authors turned to another kind of logical inference called abduction [11,13,14]. In the first part of this paper, I shall introduce a model of clinical judgment based on abductive inference and then proceed to show that this logical procedure is of particular significance for psychiatry, due to some characteristics of psychiatric semiology.…”

The thinking doctor: clinical decision making in contemporary medicine

“…However, what happens in practice is that physicians seek 'an explanation of a particular fact by finding some salient features of the particular that allow it to be explained by some more general causative principles,' a process that the American philosopher Charles Sanders Peirce described as 'abduction'. 5 The following simple examples adapted from Rapezzi, Ferrari and Branzi may help to clarify what is meant by the terms. 6 Deduction is reasoning from the general to the particular: > All the marbles in the jar are white.…”