The central problem is understanding the relation between belief and action.  Normative judgments, e.g., judgments about what’s good or what’s right, are supposed to bridge the apparent gap between what one believes is the case and what one does to transform the world.  Normative judgments thus need to interface smoothly with our beliefs, because we often seem to reason to our normative judgments and use them in reasoning further to our decisions to act. They must also, however, motivate action in a way that mere belief cannot.  In mid-20th century philosophy, cognitivists emphasized practical reasoning, while non-cognitivists focused rather on the practical, that is, the motivational aspect of norms. According to the cognitivists, normative and especially ethical claims are truth-evaluable and participate in the same kinds of logical relations as other truth-evaluable claims.  Cognitivists were thus in a position to attack the problem of how ethical and other normative claims function in our practical reasoning, but they had difficulty saying how normative beliefs are any more deeply connected to action than other beliefs.  Non-cognitivists, in contrast, denied that ethical and normative claims are, in general, truth-evaluable.  Their role, instead, is to motivate, either encouraging or discouraging particular actions.  That role does not require truth-evaluability.  One of Sellars’ teachers was C. L. Stevenson, who proposed that ethical judgments are actually expressions of pro or con attitudes towards actions, a position that came to be known as emotivism.  Sellars also paid close attention to the metaethics of R. M. Hare, who proposed that normative statements be analyzed as imperatives, commanding or forbidding an action. But Sellars believed that there is no logic of imperatives, so Hare’s analysis could not capture the role norms play in our practical reasoning.  