  Elisabeth’s worries might seem quaint and outdated. Causal relations countenanced by contemporary physics can take several forms, not all of which are of the push-pull variety. Why shouldn’t soul–body interaction simply be included as another sort of “non-mechanistic” causation (Richardson 1982)? But Elisabeth’s objection is in fact just one version of a more general worry about soul–body interaction, a worry that rests on the following thesis about causation: