The Epistemology of Clinical Reasoning: Perspectives from Philosophy, Psychology, and Neuroscience

Physicians’ clinical reasoning has been an active area of research for about 30 years. The goal of the inquiry has been to reveal the processes whereby doctors arrive at diagnoses and management plans (although as Elstein correctly points out in his discussion of this paper, the focus has been more on the former than on the latter) so that we could use this information to devise specific instructional strategies or support systems to make the acquisition and application of these skills more efficient and effective. Initially, these ‘‘clinical reasoning skills’’ were conceived as general, and content-independent, so that they could be observed in all clinicians working through any problems. That is, they were thought of as a general mental faculty, presumably rooted in the architecture of the mind, which would be brought to bear on solving clinical problems. However, the research findings did not support this viewpoint. Elstein and Shulman showed that whatever clinical reasoning was, it was definitely not skill-like, in that there was consistently poor generalization from one problem to another, a finding that ultimately sounded the death knell for evaluation methods such as patient management problems. The past 30 years have seen an accumulation of evidence, in medicine and many other disciplines, about the nature of the process, and shown the importance and centrality of knowledge. The central issue of this revised research program is achieving an understanding of how knowledge is initially learned, how it is organized in memory, and how it is accessed later to solve problems. A second research program in medical decision making also emerged from research of the early 1970s. As Elstein discusses in the companion paper, this program ‘‘views diagnosis making as opinion revision with imperfect information.’’ 1 From the decisionanalytic perspective, the best decisions arise from the application of a statistical decision rule to data; any other method is suboptimal. Thus, the research agenda is directed to identifying areas such as medicine where humans function in a suboptimal way, and attempting to understand the strategies, the heuristics and biases, they apply to arrive at these suboptimal decisions. Elstein states that ‘‘it seems to me that decision theory is at least as promising as the study of categorization processes.’’ He may well be correct. But the two schools highlight a fundamental epistemologic dilemma that the remainder of this paper addresses: Will we understand more about the nature of clinical diagnosis by focusing on the diagnostician and striving to understand the mental processes underlying diagnosis, or by focusing on the clinical environment and attempting to understand the statistical associations among features and diseases? To what extent is the world of clinical reasoning ‘‘out there’’ and comprehensible by understanding the relation between symptoms and diseases, and to what extent is it ‘‘inside’’ and understandable only by examining mental processes in detail? Further dilemmas face us as we examine the research in clinical reasoning. ‘‘Organization of knowledge’’ is viewed as a critical determinant of expertise in medicine. But it is not really clear what is meant by organization of knowledge. Is knowledge organized hierarchically with general concepts at the top, more specific scripts in the middle, and specific instances at the bottom? 4 Is it organized in networks with nodes and connections, as a symptom-by-disease matrix, as propositions with causal links, as collections of semantic axes, or as individual examples with no overarching concepts, as some of my earlier research claimed? 9 A perusal of these various studies leaves the reader with only one overall impression—that the human mind is incredibly flexible and can organize and reorganize information at will and seemingly effortlessly to give the researcher exactly what he or she wants to hear. It is no coincidence that propositional networks are disturbingly idiosyncratic and not apparently reproducible. My view is that all of these concept architectures are produced on the fly at retrieval, in order to satisfy the expectations of the researcher, and none can claim special status as the way knowledge is organized. Do you want the clinician to tell you the probability that myocardial infarction (MI) will present with referred pain to the back? Can do. The nature of the neural pathways linking the heart and the upper arm? Sure. The hair color of the last patient they saw with an MI? Red. Given this incredible diversity of knowledge from specific to general, it seems likely that any attempt to uncover a representation of knowledge consistent with a particular perspective from fairly directive probes will be successful; however, the ultimate form of this knowledge (if that is even an issue worth addressing) will remain elusive. Still, if the clinician’s mind is really that malleable, then this poses a serious challenge to the research tradition. Are there really any more ‘‘basic’’ or ‘‘primitive’’ forms of knowledge? How can we understand the nature of clinical reasoning if it appears to be this flexible? These were the questions that presented themselves as I reviewed the studies of clinical reasoning. As I thought about these issues, I began to explore other perspectives on the nature of knowledge and knowing from philosophy, psychology, and neuroscience, and started to identify common threads that, I think, can shed some light on these questions. As I did so, I found myself moving back and forth among three kinds of knowing, more or less from specific to general: