Full Idea
According to Lewis's conception, the causal powers of a property are constituted by its patterned relations to other properties in the particular Humean mosaic that is the actual world.
Gist of Idea
Lewisian properties have powers because of their relationships to other properties
Source
report of David Lewis (New work for a theory of universals [1983]) by John Hawthorne - Causal Structuralism Intro
Book Reference
Hawthorne,John: 'Metaphysical Essays' [OUP 2002], p.211
A Reaction
I just can't grasp this as a serious proposal. Relations cannot be the bottom line in explanation of the world. What are the relata? I take powers to be primitive.