If p⁰, then 1: The impossibility of thinking out cases

Abstract

Forrester’s proposed seventh style of reasoning – thinking in cases – functions as an analogous, dyadic relationship that, whilst indebted philosophically to the logical reasoning and semiotics of Charles Peirce, is prone to creating feedback loops between induction and deduction, precluding novel abductive hypotheses from advancing medical knowledge. Reasoning with a Peircean triadic model opens up the contexts and methods of meaning-making and reasoning through medical cases, and the potent influence of their genre conventions, to intellectual critical scrutiny. Vitally, it offers a third mode – abduction – that this article argues needs to be reintroduced into Forrester’s model of reasoning with cases. This article demonstrates this by applying a Peircean triadic model of reasoning to Forrester’s own model, tracing a shared genealogy but one in which the abductive element was lost. The article goes on to illustrate the explanatory and predictive potential of Peircean abductive reasoning and the necessary re-theorising of the case this entails. This argument is supported through an analysis of early case reports of what would become HIV/Aids, drawn from the Case Records of Massachusetts General Hospital series in the New England Journal of Medicine.

Closure and the Critical Epidemic Ending

“… 18 See Forrester (1996) , on what happens when we try to extrapolate from a case study, or, in Forrester’s provocative formulation, “if P, then what?” See also the Special Issue of History of the Human Sciences , reappraising Forrester’s essay, Millard & Callard (2020) , in particular the contributions by Flexer (2020) and Morgan (2020) . …”

‘If p? Then What?’ Thinking within, with, and from cases

“… 10. This points to the problem of approaching case-based thinking with the initial question ‘What is this a case of?’, a classifying question that makes sense only when the relevant typical phenomena have been established (see also Flexer, 2020). This classifying move parallels the point about mathematical proofs: Once we have the theorem, the case answer can be deduced. …”

“… 16. Flexer (2020) argues that the base form of reasoning here is abductive, not deductive. Case work, however, appears to depend on the maintenance of rich materials during the reasoning process, rather than reducted materials and inference to the best explanation. …”

Thinking in, with, across, and beyond cases with John Forrester

“…Michael Flexer – in a way that recalls Burman’s manoeuvre with Piaget – takes head-on the notion of ‘thinking in cases’ by augmenting Forrester’s tools with some borrowed from semiotician C. S. Peirce. Specifically, through treating the case as a ‘semiotic sign’, Flexer, in ‘If p 0 , Then 1: The Impossibility of Thinking out Cases’ (Flexer, 2020), argues that the creative practice of ‘abduction’ has been lost from Forrester’s thinking in cases. Flexer corrects the ‘linearity in the development of the case’ (ibid.…”