From the point of view of Jung self-knowledge is the process of individuation whereby the ego comes to know the whole self, as a whole, including the Shadow, and the manifest unconscious via the archetypes which when known appears as a mandala. This is Apollonian. Its opposite is the Dionysian loss of the self advocated by Nietzsche. Apollo was a wolf god of initiation. Dionysus was instead the only god to know death, to transition through death, like Osiris/Horus or like the avatar Christ. We might say that Dionysus brings knowledge of the Other by throwing off all constraints and going beyond all bounds while Apollo brings knowledge of the Self via initiation by taking on constraints and respecting the liminal, the thresholds. Apollo is like Brahma and Dionysus is like Shiva, and so there is another way which is nondual between them which is the way of Vishnu brought by his Avatars, such as Krishna. Krishna advises each of the Pandavas to do something against the Dharma, something evil because each of the Pandvas are too good, too perfect. Each must encounter their shadows, the evil side of their goodness. Self-knowledge concerns all the things about yourself that you do not want to confront, that you hide from yourself and others and that you deny. No one actually wants self-knowledge in the Jungian sense. And when it is pursued too far it leads to tragedy as in Oedipus. As the bird said in Four Quartets of Eliot human beings cannot stand too much reality.
In my opinion Self-Knowledge has to do with the confrontation with the nonduals of the Western Worldview within yourself and these are Order, Right, Good, Fate, Sources and Root. And normally that comes out in rare situations in a meaningful word. So there is the orderly words which we say everyday which stay within the bounds of decorum but which have little meaning, except when now and again some word seeks to put things right. Rta in Sanskrit means cosmic harmony, so the right word is the one which expresses harmony at the right time in the right context. In that context we know our selves as wrong, or on the sinister side and we put that right in ourselves. But at a deeper level there is the good word which we say to the other in need, and when we give of the abundance which is ours to give. And in that we find ourselves to be bad, or even evil and we set ourselves on a good track turning away from our harmful ways either to self or other. And yet at a deeper level there is the fateful word, spoken at some rare moment when someone’s fate hangs in the balance, even perhaps our own, which is neither free nor determined but in which we dree our wyrd. Or on yet a deeper level there is the source word, the origin of the word, where the always already lost origin bubbles up from the sources of things to light our way, and where we return to those sources, and we know our own source. And finally there is the root word, that gives rise to all the other words, more likely than not some name for God we utter in despair and then we receive grace, enlightenment, or guidance in that moment when we feel the most loss and we taste redemption. Self knowledge means to take the homeward way and to know the nondual kernel of the worldview directly within ones own self. Because ultimately the self is a face of the worldview. There is nothing in it of itself, merely an emptiness in a void that none the less manifests a fullness of life, of awareness, of social belonging together where we face our fate as a community together. No sharing of Fate no community. No giving and receiving gifts of what is good for each no community. No justice and the establishment of rights then no community. No order that is mutually recognized then no community. No community of mutual recognition then no self.
No self-knowledge except via the knowledge of the other.
No other knowledge except though ourselves.
No self/other knowledge then certainly no wisdom.
No wisdom then only desolation.