Here's an interesting interview with philosopher Peter Carruthers. He talks about introspection, self-knowledge and our mind-reading ability.
I argue is that there is a single ‘mindreading’ faculty that enables us
the perceive our own thoughts as well as the thoughts of other people.
This faculty evolved initially for social purposes, enabling us to
anticipate (and sometimes to manipulate) the behavior of other people,
as well as to better coordinate cooperative activities. But it can
likewise be turned on the self, relying on the same channels of
information that are used when interpreting the behavior of others.
Sometimes we attribute thoughts to ourselves by literally perceiving our
overt behavior. But often we rely on sensory cues that utilize the same
perceptual channels, such as our own visual imagery, or our own inner