 In this section, we will review the internal problematic of causal theories by examining how each theory fares on our battery of test cases (I)–(IV), along with other objections from time to time. This provides a simple, readily understood organization of the project of developing a causal theory of mental content, but it does this at a price. The primary literature is not arranged exactly in this way. The positive theories found in the primary literature are typically more nuanced than what we present here. Moreover, the criticisms are not arranged into the kind of test battery we have with cases (I)–(IV). One paper might bring forward cases (I) and (III) against theory A, where another paper might bring forward cases (I) and (II) against theory B. Nor are the examples in our test battery exactly the ones developed in the primary literature. In other words, the price one pays for this simplicity of organization is that we have something less like a literature review and more like a theoretical and conceptual toolbox for understanding causal theories.