[Full paper in pdf]
Abstract: I propose a new theory of scalar implicatures: the speaker should be in the same epistemic status with respect to alternatives obtained via similar transformations (e.g., replacements of a scalar items with various stronger items). This theory extends naturally to explain presupposition projection. Cases where scalar items and presupposition triggers co-occur are also accounted for. The main focus is the unification between various phenomena: scalar implicatures, free choice effects and presupposition projection. Yet, the system can be split into independent proposals for each of these issues.