LB: How did you first become interested in causation in the health sciences?
RLA: I started thinking about causation in medicine back in 2011, when I was working on my research project Causation in Science. Many of my collaborators already had an interest in philosophy of medicine, and I started thinking that if causation was complicated in physics, biology, psychology and social science, then medicine must be the biggest challenge. After all, a person is the unity of them all, as physiological, biological, mental and social beings. Also, our health is causally influenced by or even the result of what happens to us at all these levels.
LB: What would you describe as the main finding of CauseHealth now that it is drawing to a close, and what do you expect its implications to be?
RLA: In the beginning, I didn't know very much about medicine or philosophy of medicine, so I had some naïve idea about who the target group from the health profession would be. Now I understand why we have met most enthusiasm from the clinicians, since they are the ones working with individual patients. In the last year of CauseHealth, we have therefore worked more toward clinicians, especially those who feel a squeeze between the public health agenda of evidence based medicine and the clinical needs of their individual patients.
In public health, the aim of medical research is to say something general to the population, typically based on statistics from clinical studies. However, in the clinic, one will also meet patients who are not represented in the clinical trials. In CauseHealth, we have emphasised a dispositionalist understanding of causation, as it was developed by myself and Stephen Mumford in Getting Causes from Powers (OUP 2011).
Here we argue that causation is essentially complex, context-sensitive, singular and intrinsic. In medicine, this translates to
- genuine complexity rather than mono-causal models
- heterogeneity instead of homogeneity
- medical uniqueness rather than normal or average measures
- intrinsic dispositions rather than statistical correlations.
This is very different from what one would get from other theories of causation, especially empiricist theories such as the regularity theory of David Hume or the counterfactual theory of David Lewis. Scientific methodology, however, actually relies heavily on these notions of causation, in the consistent search for regularities of cause and effect under some standard, normal or ideal conditions, using correlation data or difference-makers in the comparison of such data.
By being aware of how scientific methodology and practice is influenced by ontological and epistemological assumptions from philosophy, we can empower clinicians and other health practitioners to engage critically in the development of their own profession. Our experience is that medical professionals appreciate learning more about philosophy of science in this way, which is also why Elena Rocca and I established the Centre for Applied Philosophy of Science at NMBU.
LB: As you know, at Imperfect Cognitions we have a special interest in mental health. What notion of causation do you think captures the complexities of mental health challenges?
RLA: We started from the problem of medically unexplained symptoms, that are notoriously challenging to treat within the biomedical model. They are also not your typical one cause, one effect conditions, but have a mix of physical and mental causes and symptoms, often in a unique combination for each patient. After a year or so on the project, someone challenged me on our interest in these conditions, and said that all conditions are a mix of mental and physical causes and symptoms. Most illnesses also come in combinations with others, so-called co-morbidity, so a problem is that all of medicine is divided according to the Cartesian dualism: physical versus mental health.
A dispositionalist notion of cause will give a much more holist starting point for understanding health and illness, and the clinicians that we work with are often phenomenologists but therefore also sceptical of causal talk. This is an aversion that we try to cure in CauseHealth. From our perspective, genuine holism cannot be treated as a multifactorial matter. Instead, one must start by talking to the patient and finding out more about them and their story. Most of the causally relevant information will come from their medical history, biography, life situation, diet, genetics and so on. The medical intervention is only one single factor that will interact with this vast complexity.
LB: Your project has been genuinely interdisciplinary. What have been the advantages of interacting and collaborating with people from different backgrounds?
RLA: I have learned that all disciplines and professions use causal vocabulary in different ways. 'Causal mechanism' means something very different in medicine than in molecular biology, for instance. In medicine, one thinks of mechanisms as reductionist and determinist, based on lab research on animal models. This is why 'mechanistic evidence' ranks so low in evidence based medicine. I have now started to talk about causal theories instead of causal mechanisms.