Ludwig Josef Johann Wittgenstein, the Austrian-British philosopher, was born in Vienna, the youngest of eight children. Ludwig's paternal grandfather, a convert from Judaism to Protestantism, had been a wool merchant in Saxony before moving to Vienna. Ludwig's father, Karl Wittgenstein, had, as a strong-willed boy, rebelled against a classical education, running away to America when he was seventeen. After two years he returned to Vienna and underwent a brief training in engineering. He went to work as a draftsman, designed and largely directed the construction of a steel-rolling mill, became its manager, in ten years' time was the head of a large steel company, and subsequently organized the first cartel of the Austrian steel industry. Ludwig's mother was the daughter of a Viennese banker. She was a Roman Catholic, and Ludwig was baptized in the Catholic Church. Ludwig had four...