‘The research laboratory for world destruction’ was what, in 1914, the journalist Karl Kraus presciently called Vienna. At various times in the early 20th century, its inhabitants included Adolf Hitler, Theodor Herzl (founder of modern Zionism), Sigmund Freud, Leon Trotsky, the modernists Arnold Schoenberg, Egon Schiele and Oskar Kokoschka, and Ludwig Wittgenstein, whose diary in 1931 recorded his fear of being remembered merely as the endpoint of Western philosophy. In fact, he is celebrated for transforming and rejuvenating philosophy, and Anthony Gottlieb’s Ludwig Wittgenstein: Philosophy in the Age of Airplanes is a moving portrait of his tortured, passionate and exuberant life.

Born in 1889, Wittgenstein was the ninth and last child in a family that epitomised one of the paradoxes of Vienna. In the Palais Wittgenstein, Gustav Klimt’s painting of a knight in gold armour, ramrod straight in his horse’s stirrups, dominated the marble staircase, and the Wittgensteins, according to Johannes Brahms, who frequented their musical salons, moved about ‘as if at court’. But, like 12 per cent of Vienna’s population in the late 19th century, Wittgenstein’s father and maternal grandfather were Jews – Wittgenstein’s great-­grandfather, a land agent’s son, had adopted the grand surname and, later, Christianity. The Wittgensteins were, however, as prone to default anti-Semitism as many of their Aryan neighbours. Wittgenstein tended to identify himself as only a quarter Jewish – until 1936, when he became determined to make what he called ‘a full confession’ to as many of his friends as possible of this ‘cowardly lie’.

The Wittgensteins’ ‘real religion’, says Gottlieb, was German culture, above all music. ‘It is impossible for me to say in my book one word about all that music has meant in my life. How then can I hope to be understood?’ wrote Wittgenstein to a friend. Tractatus Logico-­Philosophicus (written while he was on military service during the First World War) urged philosophers ‘to say nothing except what can be said, ie propositions of natural science’. Ethics, aesthetics, metaphysics, the mystical ‘make themselves manifest’ but are unutterable, said Wittgenstein. ‘Whereof one cannot speak, thereof one must be silent’. By culminating in this famous injunction, the book, as Gottlieb nicely puts it, ‘ends up by trying to swallow itself’. Wittgenstein had been raised ‘on a diet of the verbally inexpressible’, Gottlieb observes. Piano-playing – the only language in which she was fully fluent, according to her son – was Leopoldine Wittgenstein’s principal means of communicating with her children. Pieces they were currently learning, and concerts they had attended, were the staple of the Wittgensteins’ letters to one another. Paul, Wittgenstein’s brother, was a concert pianist who, when he lost his right arm in the First World War, commissioned a left-handed concerto from Ravel. But Wittgenstein’s father, who himself played the violin, discouraged his children’s musicality. Wittgenstein never learned an instrument in childhood, although he developed a capacity to whistle whole sections of Beethoven’s Seventh Symphony. 

Wittgenstein’s academic performance at the unacademic school he attended in Linz was ‘merely middling’, apparently, although it put him two forms higher than his fellow pupil Hitler, who was the same age. In 1908, he began studying aeronautics at Manchester (actually inventing and patenting a strange type of propeller), but, having read Bertrand Russell’s The Principles of Mathematics, he became obsessed with the philosophy of maths. In 1911, he visited Russell, then professor at Trinity College, Cambridge, who later considered their meeting ‘a great event in my life’ but, for perhaps the first fortnight of their acquaintance, found Wittgenstein ‘a bore’. ‘My German engineer’ would persist in insisting that sensory experience was inadequate for knowledge throughout Russell’s attempts to dress for dinner, refusing to admit that there wasn’t a rhinoceros in the room. But Russell soon came to love and admire Wittgenstein. Wittgenstein would treat Russell, as he did most of his friends, with alternate warmth and rebarbativeness.

Unsure whether he was any good at philosophy, Wittgenstein havered over whether to abandon engineering. During the winter vacation of 1911, he wrote a trial essay for Russell – and was enrolled at Trinity College in February 1912. He went to live in Norway a year later, however, and never actually achieved a BA. After fighting in the First World War on the Austrian side (winning several medals), writing Tractatus Logico-Philosophicus and teaching for six years at elementary schools in the Austrian Alps, Wittgenstein returned to Cambridge. He was awarded a PhD on the basis of the Tractatus and, soon, a professorship. Apart from three years of hospital war work between 1941 and 1944, he taught at Cambridge until 1947. Diagnosed with cancer in 1949, he died in 1951. The Tractatus was the only one of his numerous books to be published in his lifetime. A lot of collating and editing was required after his death. 

When Wittgenstein finished the Tractatus, he announced that all philosophical problems were now solved. But he later renounced the ‘picture theory of language’ that informed it. Language, he came to think, rather than being a static set of logical or descriptive statements which somehow mirror facts, is a set of activities. Words have meaning by virtue of the particular ‘language-game’ in which they are spoken or written. Even words for feelings and sensations, rather than being labels that we incorrigibly apply to our inner states, have meaning ‘only in the stream of life’. He was, as Gottlieb puts it, ‘turning the mind inside out’. 

Wittgenstein’s own mind was often full of self-loathing. ‘I am a worm, but through God will become a man,’ he wrote in a wartime notebook. He lost his (Catholic) faith during adolescence but couldn’t help, he said, but see everything from a religious point of view, and God as a ‘fearful judge’ (which was what his father had been) who nevertheless constituted life’s meaning. ‘God bless you always’ (or, rather, the abbreviation ‘G.b.y.a.’) was sometimes Wittgenstein’s way of signing off in letters from 1946 until his death written to Ben Richards, the last of a series of much younger men he loved. The philosopher said that his own soul was ‘more naked’ than other people’s. His letters, scrupulously edited by Gabriel Citron and Alfred Schmidt, reveal passionate love, neediness, despair, a rather heavy-handed sense of humour and intermittent contrition for his exorbitant egoism. He scours Richards’s letters for signs that he might be ending their relationship, often complaining about their ‘tone’, shortness or scarcity. There is much communication over where they should stay on their holidays together. Wittgenstein was residing in the house he had once owned in Norway, having given away all his wealth – most of it to two of his sisters; his aim had been simply to unburden himself. He is touchy over implications that he is ‘stingy’.

Richards must have casually mentioned (in an unpreserved letter) that he had grown a beard and this, wrote Wittgenstein, came as a ‘sickening shock’: ‘If one loves someone that person’s face becomes a symbol which one can’t arbitrarily change without hurting the person who has come to love it.’ Change owing to age or an accident counts as no change at all, wrote Wittgenstein, but to change the face as one would a hat or tie when one is tired of them is wilful robbery, a ‘wanton way of playing about with something which, if you love /somebody/, is not quite yours/own/ [sic]’. He was then terrified that Richards’s curt telegram response ‘means that you are braking [sic] with me’ and admitted that he had been ‘unjust & that couldn’t have been anything very new to you’. In an earlier letter, he had written, heavily underscored, ‘there is really nothing in me that is lovable’.

Wittgenstein often contemplated taking his own life (three of his four brothers died by suicide), but his last words, as he waited in vain for Richards to reach his deathbed, were: ‘Tell them I’ve had a wonderful life.’ In one of his last letters, he thanked Richards for giving him ‘happiness & joy which I never deserved’. As a postscript to an earlier letter, he enjoined: ‘May you never feel or act shallowly.’ There was never a chance that he himself would do either.