 Suppose (23) is uttered to make a claim about the town of Amherst during the last 20 years. We are looking at the snowfalls during the relevant period. For each of those actual snowfalls s, we are considering counterfactual situations r where it snowed much more than it did in s. The claim is that each of those counterfactual situations is part of a situation where the town plow removed the snow for us. To formalize what was said, we have to be able to consider for each actual snowfall s a set of counterfactual alternatives and compare the amount of snow in each of them to the actual amount of snow in s. This means that we have to be able to “go back” to the actual snowfall situations after considering corresponding counterfactual situations. To do so we have to keep track of the original situations. The available bookkeeping tools are either evaluation indices, or else situation variables and binding relations in the object language. If we want to avoid possibly unpronounced situation variables, we need two shiftable evaluation indices for (23). In the long run, even two indices wouldn’t be enough, though. Here is an example that requires three: