A variable’s absence only counts as a cause when it names a real category

Evidence

Boolean results often include both the presence of some factors (indicated by capital letters) in conjunction with the absence of others (signaled by lower-case letters). The question then arises about how the absence of a certain variable should be used to select cases with the Possibility Principle. The answer depends on what is meant by the “absence” of the variable. In some cases, the absence of a variable actually refers to the presence of a clear causal condition. For example, a Boolean analyst might code a variable for religion using two values: Protestant (i.e., P) and Catholic (i.e., p). In this case, one can argue that the absence of being Protestant (i.e., being Catholic) is a positive cause of the outcome. However, if the variable values correspond to simply Protestant and non-Protestant, there is no clear causal condition associated with the absence of the variable. In this case, where the absence of a variable is undertheorized and does not correspond to a clear positive category, the Possibility Principle cannot be easily applied. — Gary Goertz, Social Science Concepts, 1184

Categorization

• DEFINE: Clarifies the distinction between a theoretically positive absent category and a mere residual non-category.