Ontological doubling appears not just at the end of sequence of books, in Ecce Homo, where he speaks of having a privileged understanding of what constitutes health due to his tendency to become ill. Yet, here he makes the link to shamanism that is most definitive. Throughout his writing, however, the doubling of the psyche also has an epistemic structure:
To view healthier concepts and values from the standpoint of the sick, and conversely to view the secret work of the instinct of decadence out of the abundance and self-confidence of a rich life-this has been my principal experience, what I have been longest trained in. If in anything at all, it was in this that I became a master. To-day my hand is skillful; it has the knack of reversing perspectives: the first reason perhaps why a Transvaluation of all Values has been possible to me alone. [my emphasis]
In Gay Science, Nietzsche also speaks about the basis for self-overcoming, though sinking into the depths of despair and learning to think more suspiciously about the structure of reality:
Only great pain, the long, slow pain that takes its time—on which we are burned, as it were, with green wood—compels us philosophers to descend into our ultimate depths and to put aside all trust, everything good-natured, everything that would interpose a veil, that is mild, that is medium—things in which formerly we may have found our humanity. I doubt that such pain makes us “better”; but I know that it makes us more profound.
Such a descent into pain, along with exercises in mistrust of how things appear to be, make a thinker more profound. We become more profound because we become suspicious of what we used to “know”
— i.e. “things in which formerly we may have found our humanity”. One, in effect, sinks to the underworld and then comes up transformed.
This is one direction of the Nietzschean dialectic: the underworld of experience in relation to normal life. Nietzsche points out in Ecce Homo that dialectics are a sign of decadence, but nonetheless a person who is healthy overall turns even injury into an experience for learning. This is as per the historically recurrent motif of “shamanic wounding” — but one must be strong enough to begin with for any suffering to be able to yield genuine insights, rather than merely pathological notions about the world.
If this “down-going” or “going under” relates to an age-long shamanic notion of the underworld, there are other “worlds” of experience to be explores. A middle level of experience comprises the everyday world — and in shamanic terminology, there is also a realm of the heights. To reach one’s inner heights, one transcends oneself. This has the structure of tactical self-doubling. Thus Spoke Zarathustra describes the nature and meaning of self-transcendence:
One day wilt thou see no longer thy loftiness, and see too closely thy lowliness; thy sublimity itself will frighten thee as a phantom. Thou wilt one day cry: “All is false!”
There are feelings which seek to slay the lonesome one; if they do not succeed, then must they themselves die! But art thou capable of it—to be a murderer?
Hast thou ever known, my brother, the word “disdain”? And the anguish of thy justice in being just to those that disdain thee?
Thou forcest many to think differently about thee; that, charge they heavily to thine account. Thou camest nigh unto them, and yet wentest past: for that they never forgive thee.
Thou goest beyond them: but the higher thou risest, the smaller doth the eye of envy see thee. Most of all, however, is the flying one hated. [Emphasis mine].
Self-transcendence is fraught, as it involves being aware of the contemptible aspects of one’s self and moving above those cowardly elements. Consciousness is thus doubled in the process of moving between what we are and what we will to become. This doubling implies painful self-knowledge, which nonetheless one must accept if one wishes to explore the higher realm.