This open access, multi-authored volume distills the work of an interdisciplinary research project, CauseHealth, conducted from 2015 to 2019 at the Norwegian University of Life Sciences, which attempts to address theoretical and practical challenges to understanding and applying causal relationships in medicine. The project is a collaboration between philosophers and clinicians. It notes a number of the frequently recognized problems in modern clinical practice, including the reductionist tendencies in modern medicine and the sense shared by many clinicians that much current medical research, guided by the value system of evidenced based medicine (EBM), has limited relevance to the complex problems of treating a unique individual patient.

     The position around which this project is organized is that modern medicine assumes, in the spirit of a radical empiricism, a Neo-Humean view of causality; namely, that since causality itself cannot be observed, it can only be inferred from observing the repeated and consistent pattern of particular instances of a type of event following instances of another particular type of event. As a result, laudable research is expected to isolate a specific regularity between variables and collect a sufficient number of occurrences to allow that regularity to be established as causal. This leads to the well-known hierarchy in valuing evidence characteristic of EBM, with its emphasis on randomized controlled trials. But in fields studying complex phenomena, such as biology and medicine, it is impossible to isolate a single variable, and purported causal relationships are almost always statistical. In many cases the cause is not followed by the effect or the effect occurs in the absence of the postulated cause. The alternative approach suggested by the CauseHealth project is termed dispositionalism. In this view a clinical situation is best viewed as one in which multiple factors have tendencies of various strengths to bring about certain outcomes. Whether those outcomes occur in a particular situation depends upon the way these various factors interact with one another to potentiate or blunt those tendencies. If the cumulative impact crosses some threshold, the effect occurs, if not it doesn’t.

     As a result of these multiple factors and their complex interaction, each patient’s situation is unique and cannot be viewed as a simple instance of some category of cause-and-effect events. It is asserted that the clinician can best achieve an understanding of her patient, and develop a meaningful individualized plan of intervention, by identifying the interacting causal factors unique to each patient and to use this understanding to develop a shared notion with the patient of how their suffering came about and might be alleviated. Toward this end a number of heuristic diagramming methods are suggested to help the clinician organize her thinking about an individual patient as well as to share that understanding with the patient. For instance, a vector diagramming technique is used to conceptualize the net effects of multiple causes in any given case. Appropriately, the authors stress that these vectors do not imply any precise quantification of forces that can be added or subtracted mathematically. They are qualitative only.

     The book is organized in two parts. Chapters 1 through 6 provide a more theoretical discussion of the philosophical framework behind dispositionalism and its applicability to medicine, and is written mostly by philosophers. Chapters 7 through 15 are contributions by a range of clinicians, and one chapter by a patient, who have been involved in efforts to apply dispositionalism in a number of practice settings, including pain management, obesity treatment, and psychiatric illness.

     The CauseHealth project as described in this volume has a great deal to interest both the philosopher of medicine and the practicing clinician. It astutely highlights the philosophical presumptions behind much of current biomedical thinking and the resulting limitations in understanding and optimally helping our patients. The alternative approach of dispositionalism taps into a more recent tradition in the philosophy of science, as discussed for instance in the late work of Karl Popper and more recently by philosophers such as Nancy Cartwright. This approach to causality is much more congruent with the day-to-day experience of clinicians in their attempts to help individual patients. The project itself is also an inspiring example of collaborative work between philosophers and practitioners.

     But where does the clinician derive their knowledge of the multiple causal factors and their interactions for any given patient? Here the contributors put primary value on the patient’s narrative of how their own condition came about and is experienced in the broader context of the patient’s life. By careful attention to the patient’s story and empathic effort to elicit more details of that story, it is argued that the clinician and patient together come to a unique understanding of the patient. Many of the contributors to this volume rightly emphasize that this very process of empathically eliciting the patient’s life story enhances the establishment of a good therapeutic alliance with the patient and improves the patient’s expectation that they will be understood and helped. This alone has great value. But the claims here go beyond this to argue that, by attending to the narrative, the clinician is able to identify the unique pattern of causal dispositions relevant to a specific patient’s difficulties and to develop a scientifically valid plan of treatment.

     This is where I think the biggest weakness, or perhaps simply the unfinished business, of this project can be seen. If this development of a causal understanding of the individual patient is meant to be scientific enterprise, which is the assertion here, by what standards do we test its validity? In many of the chapters this process is talked about as if the causal understanding simply flows out of the careful eliciting of the patient’s narrative. But surely from any individual’s story multiple causal patterns could be hypothesized. How do we choose? How do we tell a good causal understanding from a bad one? Although never stated explicitly, a number of the contributors talk as if the patient’s own understanding of their condition has a privileged validity. But why should this be so? We have no basis to assume that if we listen carefully enough to the patient’s story, an accurate causal picture will inevitably follow. Science is meant to be a self-correcting enterprise. How are errors detected and improved upon in this methodology?

     This volume describes the intellectual product of an exciting and very promising line of interdisciplinary research. One hopes the project will continue to develop and address the above concerns and add more details of how to optimally apply the insights of dispositionalism in real-world clinical settings. But what has been accomplished so far is considerable. This book is highly recommended to philosophers of medicine and to clinicians interested in understanding, and challenging when needed, the assumptions and premises that guide their work with patients with the aim of providing more effective and individualized treatment.

   Douglas Heinrichs, MD, Ellicott City, MD

Categories: Philosophical

Keywords: causality, clinical diagnosis