1.1 The world is the totality of facts, not of things.
In his book Sex and Character, the twentythree year old Otto Weininger decries the moral decline of modern times, claims that Jews are soulless and amoral, preaches that true men must choose clear and articulated ideas. Only the spiritual life is worth living. He writes: "Logic and ethics are fundamentally the same. They are no more than duty to oneself."

Young Wittgenstein, who renounces religious beliefs, deeply admires this book.

In 1903 Otto Weininger, a homosexual, a Jew, a disparaged philosopher and lost spirit, shoots himself in the house where Beethoven died, pronouncing the final ethical duty on his own imperfect life.

Ludwig has four older brothers. His brother Hans disappears in 1903 from a boat found adrift in Chesapeake Bay. His brother Rudolf poisons himself in 1904 by drinking cyanide in a Berlin bar. His brother Kurt shoots himself in November 1916 when the troops under his command refuse to obey his orders.

Ludwig wrestles with thoughts of suicide for much of the rest of his life.