Ludwig Josef Johann Wittgenstein (26 April 1889 – 29 April 1951) was an Austrian-British philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language.[1] Described by Bertrand Russell as "the most perfect example I have ever known of genius as traditionally conceived, passionate, profound, intense, and dominating,"[2] Wittgenstein is considered by many to be the greatest philosopher of the 20th century.[3] Helping to inspire two of the century's principal philosophical movements, the Vienna Circle and Oxford ordinary language philosophy,[4] he is considered one of the most important figures in analytic philosophy. According to an end of the century poll, professional philosophers in Canada and the U.S. rank both his Tractatus Logico-Philosophicus (TLP) and Philosophical Investigations among the top five most important books in twentieth-century philosophy, the latter standing out as "...the one crossover masterpiece in twentieth-century philosophy, appealing across diverse specializations and philosophical orientations".[5] Wittgenstein's influence has been felt in nearly every field of the humanities and social sciences, yet there are widely diverging interpretations of his thought. Ludwig Wittgenstein was born in Vienna on 26 April 1889, to Karl and Leopoldine Wittgenstein. He was the youngest of eight children, born into one of the most prominent and wealthy families in the Austro-Hungarian empire. His father's parents, Hermann Christian and Fanny Wittgenstein (who was a first cousin of the famous violinist Joseph Joachim[7]), were both born into Jewish families but later converted to Protestantism, and after they moved from Saxony to Vienna in the 1850s, assimilated into the Viennese Protestant professional classes. Ludwig's father, Karl Wittgenstein, became an industrialist and went on to make his fortune in iron and steel. By the late 1880s, Karl controlled an effective monopoly on steel and iron resources within the empire, and was one of the richest men in the world.[8] Eventually, Karl transferred much of his capital into real estate, shares of stocks, precious metals, and foreign currency reserves, which were spread across Switzerland, Austria, the Netherlands and North America. Consequently, the family's colossal wealth was insulated from the inflation crises that followed in subsequent years.[9] Ludwig's mother, Leopoldine Kalmus, was born to a Jewish father and a Catholic mother, and was an aunt of the Nobel Prize laureate Friedrich von Hayek on her maternal side. Despite his paternal grandparents' conversion to Protestantism, the Wittgenstein children were baptized as Roman Catholics—the faith of their maternal grandmother—and Ludwig was given a Roman Catholic burial upon his death.[10] Ludwig grew up in a household that provided an exceptionally intense environment for artistic and intellectual achievement. His parents were both very musical and all their children were artistically and intellectually educated. Karl Wittgenstein was a hugely successful steel tycoon, but also became a leading patron of the arts. He commissioned works by Rodin and Klimt, and fully financed the Vienna Secession Building.[11] The Wittgenstein house hosted many figures of high culture—but above all, musicians. The family was often visited by composers such as Johannes Brahms, Richard Strauss and Gustav Mahler. Brahms had given piano lessons to Ludwig's two eldest sisters, and debut recitals for some of his major works were performed in the family's music rooms.[12] Ludwig's older brother Paul Wittgenstein went on to become a world-famous concert pianist, even after losing his right arm in World War I. Ludwig himself had absolute pitch perception,[13] and his devotion to music remained vitally important to him throughout his life: he made frequent use of musical examples and metaphors in his philosophical writings, and was said to be unusually adept at whistling lengthy and detailed musical passages. He also played the clarinet and is said to have remarked that he approved of this instrument because it took a proper role in the orchestra. His family also had a history of intense self-criticism, to the point of depression and suicidal tendencies. Three of his four brothers committed suicide. The eldest of the brothers, Hans—an early musician who started composing at age four—killed himself in April 1902 in Havana, Cuba. The third son, Rudolf, followed in May 1904 in Berlin. Their brother Kurt shot himself at the end of World War I, in October 1918, when the Austrian troops he was commanding deserted en masse.[14] Until 1903, Ludwig was educated by private tutors at home; after that, he began three years of schooling at the Realschule in Linz, a school emphasizing technical topics. For one school year, Adolf Hitler, who was born a mere six days before Wittgenstein, was a student there, but two grades below Wittgenstein, when both boys were 14 or 15 years old.[15] It is a matter of controversy whether Hitler and Wittgenstein even knew of each other, and, if so, whether either had any memory of the other. At the school, Wittgenstein spoke in an upper-class accent, with a slight stutter, wore very elegant clothes, and was highly sensitive and extremely unsociable. It was one of his idiosyncrasies to use the formal form of address with his classmates and to aggressively demand that they too (with the exception of a single acquaintance) address him formally, with "Sie" and "Herr Ludwig".[16] Ludwig was interested in physics and wanted to study with Ludwig Boltzmann, whose collection of popular writings, including an inspiring essay about the hero and genius who would solve the problem of heavier-than-air flight ("On Aeronautics") was published during this time (1905).[17] However, Boltzmann committed suicide in 1906.[18] In 1906, Wittgenstein began studying mechanical engineering in Berlin, and in 1908 he went to the Victoria University of Manchester to study for his doctorate in engineering, full of plans for aeronautical projects. He registered as a research student in an engineering laboratory, where he conducted research on the behaviour of kites in the upper atmosphere, and worked on the design of a propeller with small jet engines on the end of its blades. During his research in Manchester, he became interested in the foundations of mathematics, particularly after reading Alfred North Whitehead and Bertrand Russell's Principia Mathematica[19] and Gottlob Frege's Grundgesetze der Arithmetik, vol. 1 (1893) and vol. 2 (1903).[20] In the summer of 1911 Wittgenstein visited Frege and, after having corresponded with him for some time, was advised by Frege to attend the University of Cambridge to study under Russell.[21] In October 1911, Wittgenstein arrived unannounced at Russell's rooms in Trinity College and was soon attending his lectures and discussing philosophy with him at great length. He made a great impression on Russell (who soon became convinced of his genius) and G. E. Moore, and started to work on the foundations of logic and mathematical logic. Russell was by this time increasingly tired of philosophy and envisaged Wittgenstein as his successor who would carry on his work in the foundations of mathematics.[22] He was also frequently overpowered by the latter's forceful personality and criticisms. Faced with criticisms of his work by Wittgenstein, Russell wrote "I saw that he was right, and I saw that I could not hope ever again to do fundamental work in philosophy."[23] During this period, Wittgenstein's other major interests were music and traveling (he went to Iceland in September 1912), often in the company of David Pinsent, an undergraduate who became a firm friend. He was also invited to join the Cambridge Apostles, an elite secret society that Russell and Moore had both belonged to as students. Whilst in Cambridge, Wittgenstein often liked to go to the cinema.[24] Wittgenstein's father died in 1913. On receiving his inheritance, Wittgenstein became one of the wealthiest men in Europe.[25] He donated some of it, initially anonymously, to Austrian artists and writers, including Rainer Maria Rilke and Georg Trakl. In 1914, he went to visit Trakl, when the latter wanted to meet his benefactor, but Trakl died (an apparent suicide) days before Wittgenstein arrived. Although he was invigorated by his study in Cambridge and his conversations with Russell, Wittgenstein came to feel that he could not get to the heart of his most fundamental questions while surrounded by other academics. In 1913, he retreated to the relative solitude of the remote village of Skjolden at the end of the Sognefjord in Norway.[21] Here he rented the second floor of a house and stayed for the winter. The isolation from academia allowed him to devote himself entirely to his work, and he later saw this period as one of the most passionate and productive times of his life. While there he wrote a book entitled Logik, a ground-breaking work in the foundations of logic which was the immediate predecessor and source of much of the Tractatus Logico-Philosophicus. The outbreak of World War I in the next year took him completely by surprise, as he was living a secluded life at the time. He volunteered for the Austro-Hungarian army, first serving on a ship and then in an artillery workshop. In 1916, he was sent as a member of a howitzer regiment to the Russian front, where he won several medals for bravery, then in the Italian Southern Tyrol (today Trentino, in Italy), where he was taken as a prisoner of war by the Italian army in November 1918 near Trento.[21] His notebook entries during the war reflect his contempt for the baseness, as he saw it, of soldiers in wartime. Throughout the war, Wittgenstein kept notebooks in which he frequently wrote philosophical and religious reflections alongside personal remarks. The notebooks reflect a profound change in his religious life: an agnostic during his stint at Cambridge, Wittgenstein discovered Leo Tolstoy's The Gospel in Brief at a bookshop in Galicia. He devoured Tolstoy's commentary and became an evangelist of sorts: he carried the book everywhere he went and recommended it to anyone in distress (to the point that he became known to his fellow soldiers as "the man with the gospels").[26] Wittgenstein's other religious influences include Saint Augustine, Fyodor Dostoevsky and, most notably, Søren Kierkegaard, whom Wittgenstein referred to as "a saint".[27]