David Hume Pinsent (//; 24 May 1891 – 8 May 1918) was a friend, collaborator and platonic lover of the Austrian philosopher Ludwig Wittgenstein. Wittgenstein's Tractatus Logico-Philosophicus (1922) is dedicated to Pinsent's memory.
Pinsent, a descendant of the philosopher David Hume, gained a first-class honours degree in mathematics at Cambridge University, where he was described by George Thomson, future master of Corpus Christi College as "the most brilliant man of my year, among the most brilliant I have ever met." Pinsent then studied law.
He met Wittgenstein, who was two years older than he, when he was an undergraduate at Trinity College, Cambridge in 1912. He acted as Wittgenstein's subject in psychological experiments on rhythm in speech and music, and struck up a rapport based on shared interests in music and mathematics. This led to holidays together, including trips to Iceland and Norway. His diary (1912–1914) mentions his times and travels with Wittgenstein.
During World War I, Pinsent was deemed unsuitable for active military service. He trained as a test pilot instead, and worked at the Royal Aircraft Establishment in Farnborough, where he was killed in a flying accident in May 1918.
- Loners: The Life Path of Unusual Children, Sula Wolff, 1995, page 161 of 192 pages, Google Books link: Books-Google-161.
- Galison, Peter Louis; Roland, Alex (2000). Atmospheric Flight in the Twentieth Century. Springer. p. 360. ISBN 0-7923-6037-0.
- Goldstein, Laurence (1999). Clear and Queer Thinking. Rowman & Littlefield. p. 179. ISBN 0-8476-9546-8.
- Kölbel, Max (2004). Wittgenstein's Lasting Significance. Routledge. p. 150. ISBN 0-415-30517-9.
- "Ludwig Wittgenstein: Cambridge". Cambridge Wittgenstein Archive. Retrieved 2008-02-28.
- Sunningwell War Memorial — Brief biography of David Hume Pinsent
- Wittgenstein Chronology - Chronology of Ludwig Wittgenstein's life, with summaries of Pinsent's diary entries for the times they spent together.