In her mid-80s, Mary Midgley mused that she might never have become a philosopher if it weren’t for the extraordinary circumstances of wartime Oxford. In September 1939, one year into her university education, nearly all Britain’s men between 18 and 41 were conscripted into military service. For a few years, then, the University of Oxford was populated mostly by women.“The effect,” Midgley wrote, “was to make it a great deal easier for a woman to be heard in discussion than it is in normal times. Sheer loudness of voice has a lot to do with the difficulty, but there is also a temperamental difference about confidence—about the amount of work that one thinks is needed to make one’s opinion worth hearing.” What’s undeniable is the shift. Before the 1940s, only a few women in the English-speaking world had ever made careers in philosophy. In 1939, only two of Oxford’s women’s colleges even had a philosophy tutor. But the war years produced four of the most original writers on ethics of the second half of the twentieth century: Midgley, Elizabeth Anscombe, Philippa Foot, and Iris Murdoch. They found their voices, perhaps, because suddenly no one was speaking over them. But Midgley’s second conjecture, about confidence, seems a more powerful explanation. What builds confidence? The experience of being taken seriously by people one respects, certainly. And during their university years, Midgley and her peers had the full attention of their tutors. That might not have happened if they had come up in 1935 rather than in 1937, 1938, 1939. Until 1939, up-and-coming philosophers had a profile: educated at elite boys’ schools, masterfully proficient in Greek and Latin, quick-spoken and combative. Women didn’t fit the stereotype. When Anscombe—the most self-possessed and brilliant of the quartet—sought a recommendation from her post-graduate mentor, Ludwig Wittgenstein, he wrote that she was the most capable “female student” he had taught since 1930, and perhaps. . .