Radiolab – "The Turing Problem"

Date: March 19, 2012
Hosts: Robert Krulwich (host for episode), Jad Abumrad (brief appearances)
Guests: David Levitt, Jana Levin, James Gleick

Episode Overview

This episode of Radiolab delves into the life, work, and persecution of Alan Turing—mathematician, codebreaker, and pivotal figure in the creation of modern computer science and artificial intelligence. The hosts and guests explore Turing’s personal trials, his monumental contributions during WWII, and his revolutionary thinking on machines and intelligence. The discussion weaves personal biography with philosophical debate, examining not just what Turing achieved, but how his legacy resonates with ongoing questions about the nature of mind, machine, and humanity.

Major Topics & Discussion Points

1. Alan Turing’s Arrest and Conviction (01:44–03:31)

• Introduction to Turing’s Downfall: The episode opens by describing Turing’s 1952 burglary, which led to his exposure and arrest for homosexuality, still a crime in England at the time.
• Reactions and Laws:
  • Turing matter-of-factly identified the thief as an acquaintance of his boyfriend.
  • Jana Levin: "There was a law in England which criminalized, quote unquote, acts of gross indecency between adult men in public or private." (03:02)
• Outcomes: Turing is sentenced to chemical castration—estrogen implants—as an alternative to prison.

Notable Moment:

• Robert Krulwich: “When I learned this, I wondered if those policemen had any idea that the guy they were arresting was... one of the great minds of the 20th century, a war hero who... shortened World War II by at least two years.” (03:30)

2. Early Life and Loss (03:31–06:07)

• School Years: Turing is depicted as a socially awkward, bullied but intellectually vibrant adolescent at boarding school.

• First Love: He develops a bond (and unrequited love) for Christopher Morcom, a fellow student.

• Correspondence After Loss: After Morcom’s sudden death, Turing maintains a relationship through letters to Morcom’s mother, revealing deep emotional and philosophical struggles.

  • Alan Turing (letter): “I feel sure that I shall meet Morecambe again somewhere, and there will be some work for us to do together, as I believe there was for us to do here...” (05:27)

• Loss of Faith: Turing’s early religious faith fractures under the pain of bereavement.

  • David Levitt: “Turing begins to lose his faith and eventually comes to this sort of brutal conclusion that when Chris was gone, he was gone.” (05:52)

3. The Invention of the Turing Machine (06:07–09:18)

• Academic Development: At King’s College, Cambridge, Turing thrives as a mathematical loner given to vivid abstraction and solitary inspiration.
• Birth of the Turing Machine:
  • James Gleick: “It’s the world’s most impractical machine... but it's very simple. Number one, piece of tape, infinitely long... Number two, something that reads or writes ones and zeros... Number three, a set of instructions.” (07:07)
• Core Insight: The Turing machine abstracts computation as a series of mechanical, logical steps—a concept underpinning all modern computers.
  • Jad Abumrad: “Anything that could be done in mathematics mechanically could be done by his imaginary idiot simple machine.” (08:00)
• Discussion of Genius: The guests note how extraordinary it was, at the time, to imagine a single device capable of handling all forms of calculation and logic, rather than task-specific machines.

Memorable Quote:

• Jad Abumrad: “Turing’s machine is Cézanne’s watercolors. It’s Bach’s Prelude. He was a lonely 22 year old just thinking and he invented a thing that lives in the minds of every computer scientist today.” (09:18)

4. Codebreaking and Wartime Heroics (09:51–13:05)

• World War II & Enigma: Turing is recast as the prime intellect driving the decryption of German military code via the Enigma machine.
  • David Levitt: “They changed the settings every transmission... It was considered by both the Germans and the British to be uncrackable.” (10:23)
• Formation of Bletchley Park Team: An unconventional team is assembled: mathematicians, chess players, and crossword experts.
  • Jana Levin: “But the architect of the effort was really Alan Turing... he was the one who... had a very typically Turing-ish sort of breakthrough.” (10:54)
• Turing’s Machine ‘the Bombe’: He built a room-sized electromechanical device for codebreaking, exploiting predictable elements in German message openings such as “Heil Hitler.”
• Secrecy and Aftermath: Turing is not publicly acknowledged or thanked for his enormous contributions due to the work’s classified nature.

Notable Exchange:

• Robert Krulwich: “If I were King George, I would sent him a little.”
• Jana Levin: “He didn’t.” (13:03)

5. Artificial Intelligence and the Turing Test (13:05–16:43)

• Return to Theoretical Work: Back at Manchester University, Turing shepherds the first programmable computers but is already thinking further: could a machine think?
  • Jana Levin: “He really invented the field of artificial intelligence and was the first person to hypothesize about whether a machine could actually be said to think.” (13:44)
• Turing Test:
  • James Gleick: “Get a person, sit him down at a computer, have him start a conversation in text…” (14:33)
    If a machine's replies are indistinguishable from a human's, it passes the test.
• Philosophical Objections:
  • Jana Levin (quoting Sir Geoffrey Jefferson): “No machine will ever think like a human, because no machine can feel like we do, and in all the ways we do... be warmed by flattery, be charmed by sex, be angry...” (15:23)
  • Turing responds, essentially, by noting that we never truly know if another human is sentient—we only infer it.
• Provocative Conclusion: Turing extends the parallel between mind & machine:
  • David Levitt: “It’s not just that I want to build a machine that can think. It’s that we are mach[ines], that think.” (15:57)
  • Jad Abumrad: “We are just machines ourselves, just soulless biological machines.” (16:06)

6. Persecution and Suicide (16:43–19:20)

• Victimhood and Empathy: Turing identifies not just with outsider humans, but with future persecuted machines; the show draws a parallel between Turing's ostracism and the imagined plight of thinking machines.
  • Jana Levin: “For Turing, the machines were more likely to be victims, victims of prejudice...” (16:43)
• Chemical Castration: The court sentences Turing to hormone therapy intended as a ‘cure’.
  • Jana Levin: “The cure consisted of massive doses of estrogen.” (17:21)
  • David Levitt: “What it really did was it made him impotent and profoundly depressed. He grows breasts... He’s still vocally gay.” (18:03)
• Turing’s Fears: He worries that bias against his sexuality will cause his scientific theories to be dismissed.
  • Jana Levin (quoting Turing’s letter):
    “I'm rather afraid that the following syllogism may be used by some in the future. Turing believes machines think. Turing lies with men, therefore machines do not think. Yours in distress, Alan.” (18:25)
• Final Days and Suicide:
  • Turing, depressed and ostracized, dies by cyanide-laced apple in 1954, echoing the “poison apple” from his favorite film, Snow White.

7. Legacy, Apology, and Open Questions (19:20–23:31)

• Delayed Recognition: Prime Minister Gordon Brown issues a formal apology in 2009; a public campaign for Turing’s posthumous pardon fails in 2012.
• Enduring Resonance:
  • Robert Krulwich: “It’s an amazing life, and I’m in awe that anybody could have accomplished quite as much as he did and suffered as much as he did...”
• Are We Just Machines? The episode closes by returning to Turing’s philosophical challenge. The hosts debate whether accepting ourselves as machines is inspiring or dispiriting.
  • Jad Abumrad:
    “I think we're just machines, and I think we're just made of matter. I'm sorry to be giving religious opinions here, because these are religious opinions, but for me that doesn't make me feel that we're any less special.” (21:17)
  • Robert Krulwich:
    “If I built you a computer that could create equally beautiful watercolors and equally beautiful musical compositions, would you feel happier or diminished?” (21:59)
  • Jad Abumrad:
    “I feel the art I love is always art that I don't fully understand. There's some mystery there, always... And when the machine produces music that is as lovely as the music you and I love, I believe it will still be unfathomable.” (22:15–23:31)

Memorable Quotes

• Jad Abumrad (on Turing’s abstraction):
  “Turing’s machine is Cézanne’s watercolors. It’s Bach’s Prelude. He was a lonely 22 year old just thinking and he invented a thing that lives in the minds of every computer scientist today.” (09:18)

• Jana Levin (on empathy for machines):
  “For Turing, the machines were more likely to be victims, victims of prejudice, victims of injustice, victims of people like Jefferson... England was saying to Turing, you can't be what you are and we're going to change you.” (16:43)

• Turing’s own fear in a letter:
  “Turing believes machines think. Turing lies with men, therefore machines do not think. Yours in distress, Alan.” (18:25)

• Jad Abumrad (on mechanical humanity):
  “We are nothing more than flesh, blood, neurons. We are just machines ourselves, just soulless biological machines.” (16:06)

Timeline of Key Segments

• 01:44–03:31: Turing’s arrest and chemical castration
• 03:31–06:07: School years, Christopher Morcom, loss of faith
• 06:07–09:18: Turing machine explained and its revolutionary impact
• 09:51–13:05: WWII, Enigma codebreaking, the Bombe, Bletchley Park
• 13:05–16:43: Artificial Intelligence, the Turing Test, philosophy of the mind
• 16:43–19:20: Persecution, hormone therapy, Turing’s suicide
• 19:20–23:31: Apology, ongoing debate on mind-machines

Guest Attributions

• Jana Levin: Novelist and physicist, provides context about Turing’s work and personality.
• David Levitt: Biographer, gives detail on Turing’s personal life and emotional struggles.
• James Gleick: Science writer, explains the Turing machine and the Turing Test.
• Jad Abumrad: Co-host, frames the philosophical implications and emotional resonance.

Conclusion

This deeply evocative episode describes both the genius and tragedy of Alan Turing’s life. Through biography, invention, war, and philosophy, the story is at once an elegy and a challenge: what does it mean to think, to be human, to be a machine? As the hosts and guests highlight, Turing’s insights and misfortunes are inseparable from the enduring mysteries and controversies at the heart of science, technology, and society.