The idea that self-knowledge is epistemically special serves as a point of departure for the theories we have discussed thus far. Acquaintance theorists build on this idea: the acquaintance theory is an attempt to explain the special epistemic features of self-knowledge. Inner sense theorists seek to overturn this idea by arguing that self-knowledge is essentially similar, epistemically and metaphysically, to perceptual knowledge. Rationalists criticize both the acquaintance and inner sense theories.

They allege that the differences between these theories are of little significance, since both ignore what is truly distinctive about self-knowledge. According to the rationalist critique, both acquaintance theorists and inner sense theorists construe self-knowledge as basically similar to perceptual knowledge in that it proceeds through observation, although on the acquaintance theory the method of observation is special and provides an especially high level of justification for self-attributions. Since both theories construe self-knowledge as justified through an observational process-an introspective glance or the operation of inner sense-they both construe selfknowledge as a kind of empirical knowledge. Rationalists charge that the point of contention between these theories is, then, relatively trivial: it concerns only whether self-knowledge involves a distinctive type of observation.