What is the Exclusion Problem?

The philosophical literature contains at least three formulations of the problem of causal exclusion. Although each of the three most common formulations targets theories according to which some effects have ‘too many determiners’, no one is reducible to either of the others. This article proposes two ‘new’ exclusion problems and suggests that exclusion is not a single problem but a family of problems unified by the situations they problematize. It is shown, further, that for three of the most popular attempts to solve one or another of the ‘old’ problems, each remains vulnerable to one of the ‘new’ exclusion problems.