 As emphasized in  §1.1  above, any theory of events or facts can easily be transposed into a theory of the values of token variables. And, plausibly, token variables are individuated by their values. So, when it comes to token influence between variables, we will face many of the same questions and debates about the causal relata: how fine- or coarse-grained are they? When are two variables the same; when are they different? Can variables include absences or omissions as values? There is, however, an additional question to be a asked about the metaphysics of variables: when can some collection of variable values be grouped together into a single variable? All agree that the potential values of a variable must exclude each other. That is: if \(v\) and \(v^*\) are two values of the variable \(V\), then it should be impossible that \(V=v \wedge V=v^*\) (here, \(V=v\) is the proposition that the variable \(V\) takes on the value \(v\), and likewise \(V=v^*\) is the proposition that the variable \(V\) takes on the value \(v^*\)).