This is part of the (excellent) seminar series on Probabilities, Propensities, and Conditionals convened by Mauricio Suárez at the Institute of Philosophy. You can find more details at their website: http://philosophy.sas.ac.uk/about/ppc-seminar-donald-gillies-30-Sept

30 September 2014, 17:15 – 19:00

Objective Probability, and Conditional Reasoning Seminar: Room G34, Senate House, WC1
Causality, Propensity, and Simpson’s Paradox
Donald Gillies (UCL)

Contemporary medicine uses indeterministic causes, i.e. causes which do not always give rise to their effects.  For example, smoking causes lung cancer but only about 5% of smokers get lung cancer.  Indeterministic causes have to be linked to probabilities, but the nature of this link is problematic.  Seemingly correct principles connecting causes to probabilities turn out to be liable to counter-examples.  The present paper explores this problem by interpreting the probabilities involved as propensities.  This associates the problem of linking causality and probability closely with Simpson’s paradox, thereby suggesting a way in which the problem might be resolved.