 We can imagine a society (call it the action-theoretic state of nature) getting by with only naive rationalization. But there is room for improvement in their practice of calculative reason-giving, and here’s a short way to see how. Agents restricted to naive rationalizations will say “I’m Bing because I’m Aing,” when Bing is an action that is a part of Aing, and they are Aing. But such parts of actions often come in sequence, one after another. So such an agent can, at a particular time, be executing a containing action, i.e., Aing, but not executing a subsidiary action, Bing, if Bing is an action that is a part of Aing, but one which comes earlier or later on in the sequence. Now, if, at a particular time, an agent is not executing an action (again, Bing), then when someone asks if he’s Bing, he’ll say he’s not. So it’s easy to put agents restricted to naive rationalizations in the position of saying both that they’re Bing, and that they’re not Bing. (E.g., “I’m Bing because I’m Aing, but I’m not Bing.”) That’s potentially confusing. 