The Program Model, Difference-makers, and the Exclusion Problem

How do the notions of programming and difference-making relate to one another? A higher-level property programs for an effect just in case, intuitively, the actual realizer of the property at any lower level gives rise to a realizer of the effect and any possible realizer at that level would also have done this. A higher-level property makes a difference to the effect just in case its presence programs for the effect and, in addition, its absence programs for the absence of the effect. Christian List and Peter Menzies argue for the capacity of the difference-making model to explain away the exclusion problem raised for physicalists by Jaegwon Kim. But the program model, developed in earlier work by Frank Jackson and Philip Pettit, offers a simpler and more straightforward way of handling the challenge.