Sex and Character
Male activity and female passivity
The male aspect is active, productive, conscious and moral/logical, while the female aspect is passive, unproductive, unconscious and amoral/alogical. Weininger argues that emancipation should be reserved for the "masculine woman", e.g. some lesbians, and that the female life is consumed with the sexual function: both with the act, as a prostitute, and the product, as a mother.
Forgoing love for the absolute
Woman is a "matchmaker". By contrast, the duty of the male, or the masculine aspect of personality, is to strive to become a genius, and to forgo sexuality for an abstract love of the absolute, God, which he finds within himself.
Nature of genius
A significant part of his book is about the nature of genius. Weininger argues that there is no such thing as a person who has a genius for, say, mathematics, or music, but there is only the universal genius, in whom everything exists and makes sense. He reasons that such genius is probably present in all people to some degree.
Negative archetypal characteristics of Jews
In a separate chapter, Weininger, himself a Jew who had converted to Christianity in 1902, analyzes the archetypical Jew as feminine, and thus profoundly irreligious, without true individuality (soul), and without a sense of good and evil. Christianity is described as "the highest expression of the highest faith", while Judaism is called "the extreme of cowardliness". Weininger decries the decay of modern times, and attributes much of it to feminine, and thus Jewish, influences. By Weininger's reckoning everyone shows some femininity, and what he calls "Jewishness".
Added notoriety due to Weininger's suicide
Weininger's suicide in the house in Vienna where Beethoven had died, the man he considered one of the greatest geniuses of all made him a cause célèbre, inspired several imitation suicides, and turned his book into a success. The book received glowing reviews by August Strindberg, who wrote that it had "probably solved the hardest of all problems", the "woman problem".