The book which followed, "_Die fröhliche Wissenschaft_" ("The Joyful Science") continued the same task. The first edition contained four parts and was published in 1882. In 1887 a fifth part was added. Nietzsche had now completed his plowing and was ready to sow his crop. He had demonstrated, by practical examples, that moral ideas were vulnerable, and that the Ten Commandments might be debated. Going further, he had adduced excellent historical evidence against the absolute truth of various current conceptions of right and wrong, and had traced a number of moral ideas back to decidedly lowly sources. His work so far had been entirely destructive and he had scarcely ventured to hint at his plans for a reconstruction of the scheme of things. As he himself says, he spent the four years between 1878 and 1882 in preparing the way for his later work. "I descended," he says, "into the lowest depths, I searched to the bottom, I examined and pried into an old faith on which, for thousands of years, philosophers had built as upon a secure foundation. The old structures came tumbling down about me. I undermined our old faith in morals."[2] This labor accomplished, Nietzsche was ready to set forth his own notion of the end and aim of existence. He had shown that the old morality was like an apple rotten at the core--that the Christian ideal of humility made mankind weak and miserable; that many institutions regarded with superstitious reverence, as the direct result of commands from the creator (such, for instance, as the family, the church and the state), were mere products of man's "all-too-human" cupidity, cowardice, stupidity and yearning for ease. He had turned the searchlight of truth upon patriotism, charity and self-sacrifice. He had shown that many things held to be utterly and unquestionably good or bad by modern civilization were once given quite different values--that the ancient Greeks considered hope a sign of weakness, and mercy the attribute of a fool, and that the Jews, in their royal days, looked upon wrath, not as a sin, but as a virtue--and in general he had demonstrated, by countless instances and arguments, that all notions of good and evil were mutable and that no man could ever say, with utter certainty, that one thing was right and another wrong. The ground was now cleared for the work of reconstruction and the first structure that Nietzsche reared was "_Also sprach Zarathustra_" ("Thus Spake Zoroaster"). This book, to which he gave the sub-title of _"Ein Buch für Alle und Keinen_" ("A book for all and none"), took the form of a fantastic, half-poetical half-philosophical rhapsody. Nietzsche had been delving into oriental mysticism and from the law-giver of the ancient Persians he borrowed the name of his hero--Zoroaster. But there was no further resemblance between the two, and no likeness whatever between Nietzsche's philosophy and that of the Persians.