Through working for Gretl, Wittgenstein was brought back into Viennese society and, eventually, back into philosophy. While the Kundmangasse house was being built, Gretl and her family continue to occupy the first floor on the Schönbrunn Palace. Her eldest son, Thomas, had recently returned from Cambridge and was now reading for a Ph. D. at the University of Vienna. At Cambridge he had met a Swiss girl by the name of Marguerite Respinger and had invited her to Vienna. With her, Wittgenstein began a relationship which he at least came to regard as a preliminary to marriage, and which was to last until 1931. She was, as far as anybody knows, the only woman with whom he fell in love.

Marguerite was a lively, artistic young lady from a wealthy background, with no interest in philosophy and little of the devout seriousness that Wittgenstein usually made a prerequisite for friendship. Her relationship with Wittgenstein was, presumably, encouraged by Gretl, although some of his other friends and relations were bemused and rather less than pleased by it. She first met Wittgenstein when, after an accident at the building site, he had hurt his foot and was staying with Gretl's family to convalesce. She was part of a group of young people — which included Thomas Stonborough and the Sjögren brothers, Talle and Arvid — which gathered round his bed to listen to him read. He read something from the Swiss writer Johann Peter Hebel, and, she reports: 'I felt again at home and moved by hearing it read with such deep understanding.' ...

... Wittgenstein and Marguerite began to see each other almost daily. While she was in Vienna, Marguerite attended the art school, and after her lessons would go to the Kundmangasse building site to meet Wittgenstein. They would then go together to the cinema to see a Western, and eat together at a café a simple meal consisting of eggs, bread and butter and a glass of milk. It was not quite the style to which she was accustomed. And it required a certain degree of courage for a respectable and fashionable young lady like herself to be seen out with a man dressed, as Wittgenstein invariably was, in a jacket worn at the elbows, an open-neck shirt, baggy trousers and heavy boots. He was, moreover, nearly twice her age. She would on occasion prefer the company of younger, more fashionable, men like Thomas Stonborough and Talle Sjögren. This both puzzled and angered Wittgenstein. 'Why', he would demand, 'do you want to go out with a young thing like Thomas Stonborough?'

... Early in the summer [1931] he invited Marguerite to Norway, to prepare, as he thought, for their future life together. He intended, however, that they should spend their time separately, each taking the advantage of the isolation to engage in serious contemplation, so that they would be spiritually ready for the new life that was to come. ... After two weeks she left for Rome to attend he sister's wedding, determined that the one man she was not going to marry was Ludwig Wittgenstein. Not only did she feel she could never rise to meet the demands a life with Wittgenstein would present; also, and equally important, she knew Wittgenstein would never be able to give her the sort of life she wanted. He had made it clear, for example, that he had absolutely no intention of having children, thinking that to do so would simply be to bring another person into a life of misery.