Know Thyself

To know oneself is to know an integral part of reality: it is to know the interior of the only mind a non-telepath could gaze into.  It is actually the only mind a non-telepath can prove the existence of to begin with!  This alone makes introspection philosophically significant despite how often it gets overlooked beyond the bare minimum acknowledgment (seemingly in part because of the current Western obsession with epistemologically inferior issues like science), but it also gives one the ability to prove far more to oneself about one's own consciousness than the fact that it simply exists.  After all, there is much more to rationalistic introspection and to the human mind than realizing in an explicitly philosophical manner that one exists as a consciousness.

All of one's mental states, from rationalistic awareness to layered emotions, are immediately accessible to each person.  Each of them can be recognized and understood.  This, just like knowledge about logic itself or about sensory perceptions, is still a subject of knowledge, and I mean knowledge in the only true sense of the concept--absolute certainty that a particular thing is true.  Just as the existence of one's consciousness cannot be a matter of mistaken perception, the contents of one's consciousness (the presence of individual thoughts, feelings, and desires) cannot be an illusion metaphysically or epistemologically speaking.  They must also exist and be directly knowable with absolute clarity.

One's own personality, memories, perceptions, feelings, desires and degree of philosophical awareness are all things that are themselves parts of reality in that it is true that each person has their own mental states that at least reflect their own consciousness.  This is more than something that everyone knows, or else no one would mistake the subjective experience behind these components of human consciousness for things that have nothing to do with any part of reality--and if no adult had yet to distinguish between basic experiences and the realization that the subjective mental states behind those experiences objectively tell someone about their own self, why would people talk as if they have never realized this?

Knowing oneself is not irrelevant to understanding reality.  This is because a person's preferences, subjective experiences, and other aspects of their mind, which is itself something that objectively exists, are real parts of their consciousness.  They just do not shape parts of reality beyond them, such as logical truths, the behavior of the external world, and the thoughts of any other minds that might exist.  Just because preferences and personalities do not ground reality does not mean that it is not true that preferences and other subjective mental states or characteristics of minds exist.  They most certainly do, and it is ironically introspective truths that stand alongside logical truths as being more foundational than the external world itself.