Alan Turing Proved No Computer Will Ever Solve This

In 1936, a 23-year-old in Cambridge proved that there are questions no computer will ever answer, no matter how fast it gets. To prove it, Alan Turing had to invent the computer itself, on paper: the Turing machine, and the universal machine that every phone and laptop is built on. This is the story of Hilbert's dream of a machine that could decide all of mathematics, the halting problem and the beautiful proof that kills it, how the same young man helped break Enigma at Bletchley Park, asked whether machines can think, and was put on trial by the country he had helped to save. CHAPTERS 0:00 1936: the question no computer can answer 0:47 Hilbert's dream: a machine for all of mathematics 2:10 Gödel breaks the first wish 2:40 The boy who didn't fit in 5:06 The Turing machine, explained 7:11 The universal machine (your phone) 7:55 The halting problem 9:23 The proof: a program that can't exist 11:45 Bletchley Park and Enigma 13:06 The Bombe 15:09 Can machines think? The Turing test 17:32 The trial 19:12 Legacy: what no machine will ever do A NOTE ON THE STORY Turing's own proof is phrased in terms of "circle-free" machines; the name "halting problem" came later. The estimate that codebreaking shortened the war by about two years is one historian's and is debated. The inquest ruled Turing's death suicide; some historians argue an accident cannot be ruled out. Document excerpts on screen quote the original wording where shown, and are labelled "paraphrased", "translated" or "summary" otherwise. The study mentioned at 2025 is Jones & Bergen (UC San Diego), a three-party Turing test. SOURCES • A. M. Turing, On Computable Numbers (1936); Computing Machinery and Intelligence, Mind (1950) • Andrew Hodges, Alan Turing: The Enigma (1983) • D. Hilbert & W. Ackermann, Grundzüge der theoretischen Logik (1928); K. Gödel (1931); A. Church (1936); H. G. Rice (1953) • F. H. Hinsley, British Intelligence in the Second World War • Bletchley Park Trust; The National Museum of Computing IMAGES (Wikimedia Commons) Public domain / CC0: Alan Turing at age 16; Alan Turing (1951); Hilbert; Young Kurt Gödel as a student in 1925; Christopher Morcom Portrait; Human computers - Dryden; NACA Computers Take Readings From Manometer Boards (GRC-1949-C-23011); Boy on bicycle LOC npcc.04248; PaperTapes-5and8Hole; Black smartphone in hand (Unsplash); R.M.S. Berengaria; Atlantic convoy, 1942; U-boat Warfare 1939-1945 C3780; Colossus; Chess game Staunton No. 6 perfil view 8; Child reading a book, NINO F Scholten photographic print 04 105; Drawing, Broken Columns, View from the Parthenon, Athens, April 1869 (CH 18199569); Julius Knorre - Altstädtischer Markt in Königsberg. Kunstdruck aus dem Jahr 1930; Enamel cups on a table (Unsplash). Creative Commons, used unmodified with credit: Bletchley Park Mansion, by DeFacto (CC BY-SA 4.0); Enigma-IMG 0487-black, by Rama (CC BY-SA 2.0 fr); Hut 8, Bletchley Park, by Bibeyjj (CC BY-SA 4.0); The-baby-replica-mosi-manchester-gt-britain-1, by KGGucwa (CC BY-SA 3.0); Pilot ACE in the Science Museum, by Philafrenzy (CC BY 2.0); Statue of Alan Turing, Sackville Gardens - geograph.org.uk - 8107705, by Eirian Evans (CC BY-SA 2.0); 20130808 Kings College Front Court Fountain Crop 01, by Dmitry Tonkonog (CC BY-SA 3.0); 20130215 Kings College Chapel Hi-res 01, by Dmitry Tonkonog (CC BY-SA 3.0); Sherborne Abbey (9471713029), by Peter Broster (CC BY 2.0); River Cam at Grantchester Meadows, England (44199469135), by R Boed from The Netherlands (CC BY 2.0); 2019-08-04 Brunsviga calculator, by Maksym Kozlenko (CC BY-SA 4.0); Telescope, 4 draw, in shagreen brass caps, by unknown author (CC BY 4.0); 3 Hourglasses Wellcome L0011331, by unknown author (CC BY 4.0); Nassau Hall, Princeton University, by Alexander Friedman (CC BY-SA 4.0); Bletchley Park Bombe, by Mike Peel (www.mikepeel.net) (CC BY-SA 4.0); Common sunflower (Helianthus annuus), by Dandy1022 (CC BY-SA 4.0); The Old Sessions House, Knutsford (geograph 5061878), by Matt Harrop (CC BY-SA 2.0); Police Blue Lamp - geograph.org.uk - 3652794, by Gerald England (CC BY-SA 2.0); Red Apple, by Abhijit Tembhekar from Mumbai, India (CC BY 2.0); London, Palace of Westminster -- 2016 -- 4800, by Dietmar Rabich (CC BY-SA 4.0); Datacenter Server Racks (22370909788), by Carl Lender from Sunrise, USA (CC BY 2.0); John Owens Building, Manchester University 8550549870, by Mikey (CC BY 2.0); Sherborne - School - geograph.org.uk - 6950347, by Colin Smith (CC BY-SA 2.0). Maps: Natural Earth (public domain). Narration: the channel's own cloned voice (CosyVoice3). Script and animations: original. #AlanTuring #Computers #History