Nietzsche says that Apollo is the "lucent one" and, in this, he is the god of template and measure, the god of the tangible, of the light that reigns over the inner world of illusion and fantasy. Apollo is the principle of belief and the act of relying on belief.
Imagine that you are in a small rowboat on an immense, raging sea. You are assailed by huge waves, and you are hanging on to the sides of this frail craft, believing in the power of the rowboat to stay afloat amidst the furious torment of this world. We can say that the "most magnificent expression" of this craft is the god Apollo,"whose looks and gestures radiate the full delight, wisdom, and beauty of "illusion." (Winslow Homer's Gulf Stream)
When we are seized with doubt, and our current beliefs are shattered, even from the very depths of our convictions, then we are in a position to apprehend the rapture of Dionysus. The chariot of Dionysus is bedecked with garlands, and panthers stride beneath the yoke. The power of the universe is now manifest in his transport, to the glorious satisfaction of the primordial man. Dionysus attends to the supreme significance of musical dissonance which shatters the teeming beliefs of individuals with physical intoxication and narcotic potions, and with the powerful approach of spring which penetrates with joy that whole frame of nature. So stirred an individual forgets himself completely.
The Dionysaic is also developed into something quite different that reveals our deepest suffering. We realize that no action can work change in the external condition of things; no comfort any longer avails. We see that supposed laws only serve to raise "appearance" to the status of "reality," thereby rendering impossible the genuine understanding of that reality--the dreamer moves ever faster in sleep. This scenario is perhaps best described as tragic.
Dionysaic Man might be said to resemble Hamlet. The truth once seen, man is aware everywhere of the ghastly absurdity of existence; we comprehend the symbolism in Ophelia's face. Apollo rescues us from a direct identification with the Dionysaic music and allows us a way to understand that which is, in fact, beyond Apollo's realm, per se.
Nietzsche writes, "Whenever the Dionysaic forces become too unruly . . . we are safe in assuming that Apollo is close at hand, though wrapped in a cloud, and that the rich effects of his beauty will be witnessed by a later generation. . . ."