 The term “introspection”’—literally, “looking within”—captures a traditional way of conceiving how we grasp our own mental states. This term uses a spatial metaphor to express a divide between the “inner” world of thought and the “external” world. The term “introspection” is used in various ways in the self-knowledge literature. Perhaps the most common usage is that suggested by the term’s literal meaning: on this usage, introspection is inner observation—or “inwardly directed attention” (Goldman 2006: 246)—that, when successful, yields awareness of a mental state. The notion that inner observation is the special method by which we achieve self-knowledge is central to the acquaintance and inner sense accounts (see  3.1  and  3.2  below).