The form of causation in health, disease and intervention: biopsychosocial dispositionalism, conserved quantity transfers and dualist mechanistic chains

David W. Evans, Nicholas Lucas, Roger Kerry

Causation is important when considering: how an organism maintains health; why disease arises in a healthy person; and, how one may intervene to change the course of a disease. This paper explores the form of causative relationships in health, disease and intervention, with particular regard to the pathological and biopsychosocial models. Consistent with the philosophical view of dispositionalism, we believe that objects are the fundamental relata of causation. By accepting the broad scope of the biopsychosocial model, we argue that psychological and social constructs be considered objects. We think that this 'biopsychosocial dispositionalism' offers the flexibility required to describe causation throughout health, disease and intervention pathways. When constructing mechanistic chains to describe causative pathways, we argue that an object will causally connect with others through actions; transfers of energy from one object to another, initiated by the manifestation of one or more dispositional property. Finally, our analysis of causative interactions utilises the concept that a common form of interaction exists between disease and intervention pathways. This common form will always be an object, but the mode of interaction will vary with each disease. We describe how intervention may act through objects being shared between converging mechanistic chains, or through the removal and/or insertion of objects in such chains. We believe that this analysis provides novel insight to the forms of causative transactions that can occur. In addition, we hope that the findings of this analysis represent the first step towards developing a framework for appraising the composition of mechanistic theories.