 A number of contemporary philosophers have explored an alternative counterfactual approach to causation that employs the structural equations framework. (Early exponents include Hitchcock 2001, 2007; Woodward 2003; Woodward and Hitchcock 2003.) This framework, which has been used in the social sciences and biomedical sciences since the 1930s and 1940s, received its state-of-the-art formulation in Judea Pearl’s landmark 2000 book. Hitchcock and Woodward acknowledge their debt to Pearl’s work and to related work on causal Bayes nets by Peter Spirtes, Clark Glymour, and Richard Scheines (2001). However, while Pearl and Spirtes, Glymour and Scheines focus on issues to do with causal discovery and inference, Woodward and Hitchcock focus on issues of the meaning of causal claims. For this reason, their formulations of the structural equations framework are better suited to the purposes of this discussion. The exposition of this section largely follows that of Hitchcock 2001.