The Tragic Myth

In The Birth of Tragedy from 1872, Nietzsche studied the Ancient Greek culture, specifically the Greek Tragedy. He posed the question of why the Greeks developed such an art form. Why did a people whose cultural life otherwise seemed so life-affirming and bright suddenly begin writing complex dramas where the lonely individual took the wrong step in life, abruptly finding themselves at the mercy of the gods?
For Nietzsche, who is already beginning to reveal the foundation of his philosophy, there is a truth about life to be found in tragedy. True art, he says, must reflect life and thus be amoral, because life in its very core is not moral, but rather, organic. And as organic life has no moral guidance but only primal natural laws, through which it both creates and destroys lesser life such as human beings and animals, it must be regarded as "anti-life" to morally condemn natural things such as death, pain or tragedy. Herein lies the foundation to what Nietzsche sees as brilliant in the Greek tragic myth: it celebrates life unconditionally and captures its essence of existence without flinching or defending itself with ethical principles. It's a clear expression of life itself.
But for Nietzsche, this conclusion is only the platform. For tragedies to be made, man must invent myths. The Greek religious life was filled with hundreds upon hundreds of gods, goddesses and mystic tales from which the Greeks drew inspiration for their art. This realization becomes the central idea that Nietzsche wants to make about art: without a strong and rich life of myths and magic tales, the culture slowly decays from within due to lack of nourishment.
Art is not created from moral or rational principles, but from the depth of the soul of a people. The myth is the expression of that unique soul, but as soon we try to "objectify" or rationally explain its relevance, we slowly kill our cultural life and replace it with a clinic, materialist worldview. This worldview is the modern one, where we have literally killed the belief in religion, passion, magic and myth, because we no longer understand their function. We search for "objective" answers to the myth itself and unsurprisingly we find none, because the truth about life, according to Nietzsche, does not lie in the myth itself, but in its metaphorical expression of life. We cannot discover Zeus up on Mount Olympus, nor will we ever find the Cyclops that almost killed Odysseus, because these are simply metaphors to communicate something about our existence that cannot be adequately explained otherwise.
Nietzsche sees a corrolation between myth and perception of reality. We cannot gain direct access to any objective truth, the "thing in itself"; instead, we interpret it through subjective symbolism, just like we perceive life through the metaphor in art. In his groundbreaking work called On Truth and Lies in a Nonmoral Sense, he writes:
The various languages placed side by side show that with words it is never a question of truth, never a question of adequate expression; otherwise, there would not be so many languages. The "thing in itself" (which is precisely what the pure truth, apart from any of its consequences, would be) is likewise something quite incomprehensible to the creator of language and something not in the least worth striving for. This creator only designates the relations of things to men, and for expressing these relations he lays hold of the boldest metaphors.
This conclusion is the beginning to an aesthetic manifesto, upholding the subjective experience as more worthwhile than the search for objective truth - a truth that Nietzsche says we cannot possibly gain access to anyway. The only way for us to live in harmony is to accept the limitations of our human conditions and find truth in the metaphor of art. As he famously proclaims in The Birth of Tragedy: "the existence of the world is justified only as an aesthetic phenomenon."