Causation and Genetic Diseases. A Philosophical Study of Causal Selection Practices in Epidemiology

Causal selection refers to the common practice of singling out one cause among all known causes
of some event, and calling it "the" cause. Suppose that a fire breaks out in a house, and we say
that this fire is caused by a short circuit. In this case we know that other factors (such as the
presence of combustible material and oxygen) are causally relevant, but we still consider the short
circuit to be the most important or decisive cause. This is an instance of causal selection.
Causal selection not only occurs in everyday causal discourse, but also in biomedical research.
Epidemiologists tend to single out genetic factors for inclusion in disease explanations, and to
relegate other factors to the background. For example, when epidemiologists put forward the
BRCA 1 and BRCA 2 genes as causes of breast cancer, they are well aware that these genes are
only two of the many factors involved in an incidence of breast cancer. Nevertheless, the genetic
causes are emphasised.
My project investigates these causal selection practices in epidemiology and provides instruments
for their critical assessment. I study four diseases intensively: phenylketonuria, tuberculosis, breast
cancer and obesity.