Podcast Summary

Podcast: Everything Everywhere Daily
Host: Gary Arndt
Episode: Six Degrees of Separation
Date: September 8, 2025

Overview

In this episode, Gary Arndt delves into the fascinating concept of the “Six Degrees of Separation” theory: the idea that any two people on Earth are connected through at most six social links. Arndt traces the historical development of the theory, discusses its impact on both science and pop culture (especially through the “Six Degrees of Kevin Bacon” game), and explores related concepts in mathematics, academia, and even ecclesiastical authority.

Key Discussion Points & Insights

What is Six Degrees of Separation?

• Definition: The idea that any two individuals can be connected through a chain of, at most, six acquaintances.
• Origins:
  • Hungarian author Frigyes Karinthy speculated in 1929 that technological advances had shrunk the world to a handful of network connections.
  • Karinthy’s story Chains is an early literary statement of the idea.
  • Quote ([06:01]): “He speculated that advances in communication and travel had shrunk the world such that everyone was linked through only a handful of connections.”

The Milgram "Small World" Experiment

• Details:
  • Conducted by Stanley Milgram (1967).
  • Enlisted ~300 people in Nebraska/Kansas to transmit a folder to a Boston stockbroker through acquaintances only.
  • Only 64 chains reached the target, averaging about 5-6 intermediaries.
  • Analysis:
    • “Milgram himself never used that wording. He instead concluded that people live in a small world, meaning that social networks are much more tightly interconnected than intuition would suggest.” ([10:45])
  • Criticisms:
    • High dropout rate.
    • Sampling bias (mostly middle-class Americans).
    • Possibly underestimated actual social connectivity.

Theoretical & Technological Advances

• Network Science:
  • Duncan Watts & Steven Strogatz’s 1998 paper provided a mathematical explanation for small-world networks.
  • Their work demonstrated how tightly clustered groups can still be closely connected to distant nodes through just a few “shortcuts.”
  • “Their 1998 paper... is one of the most influential studies in modern complexity science.” ([15:08])
• Social Media:
  • Modern networks (Facebook, LinkedIn) have made it possible to empirically measure connectivity.
  • Studies suggest the average distance between two users may be just three or four steps.

The Six Degrees of Kevin Bacon Game

• Origins:
  • Invented in 1994 by college students observing Kevin Bacon’s wide-ranging film connections.
  • Connect any actor to Kevin Bacon through movies, counting each shared film as one degree.
• Notable Quotes:
  • “They joked that Kevin Bacon is the center of the universe and began challenging each other to link any actor to Kevin Bacon through co-stars.” ([18:26])
• Popularization:
  • Mentioned on MTV’s Jon Stewart show in 1994, becoming a pop culture phenomenon.
  • Kevin Bacon later embraced the game, even creating a charitable network called SixDegrees.org.

Bacon Numbers

• Definition:
  • Bacon Number 0: Kevin Bacon himself.
  • Bacon Number 1: Acted with him.
  • Bacon Number 2: Acted with someone who acted with him, etc.
• Examples:
  • Peter Dinklage, who stars with Bacon in the recent Toxic Avenger remake, has a Bacon Number of 1. ([22:10])
  • “It’s surprisingly difficult to find a regular working actor with a Bacon Number greater than three.” ([23:40])
  • Highest found: General William Rufus Schaffner, with a Bacon Number of 10.
• Personal Fun Fact:
  • Gary Arndt reveals his own Bacon Number is 5, tracing a path through acquaintances and film appearances. ([26:47])

Is Kevin Bacon Really the "Center"?

• Research:
  • Calculations using IMDb found that Rod Steiger used to be the most central actor; as of 2025, it’s Eric Roberts.
  • “The Oracle of Bacon website calculates this periodically and the new center of the acting universe as of January 2025 is Eric Roberts.” ([29:10])

Academic and Other "Degrees" Games

Erdős Number

• Origin:
  • Measures collaborative distance from mathematician Paul Erdős (based on co-authoring papers).
• Examples:
  • Albert Einstein: Erdős Number 2.
  • Milton Friedman: Erdős Number 3.
• Bacon-Erdős Number:
  • Sum of Bacon and Erdős Numbers; very rare.
  • Lowest known: Daniel Kleitman, with a total of 3.
    • “...he co-authored a paper with Erdős himself and briefly appeared in Good Will Hunting...” ([32:41])
  • Other holders include Danica McKellar, Natalie Portman, Carl Sagan, etc.

Morphy Number

• Definition:
  • Chess analog, based on official games linking to 19th-century champion Paul Morphy.
• Historical/Religious Analogy:
  • Early Christian communities used similar succession concepts (apostolic succession) to establish lineage and authority.

Notable Quotes & Memorable Moments

• “You may have noticed on occasion that friends you have from totally different parts of your life somehow know each other. It often comes as a surprise, but it actually shouldn’t.” — Gary ([00:00])
• “The Milgram Experiment, you might remember, was a test to see how far people would go when they thought they were shocking other people to follow instructions.” ([08:20])
• “Studies have repeatedly shown that the average distance between any two users is indeed surprisingly short, often just three or four steps, making Milgram’s intuition prescient.” ([16:55])
• “Kevin Bacon himself initially didn’t like it, but eventually embraced the idea...” ([20:46])
• “The concept of apostolic succession still underpins Catholic, Orthodox and Anglican understandings of church authority today.” ([36:50])
• Concluding: “So it turns out that Walt Disney had it right. It is a small world, after all.” ([38:30])

Key Segment Timestamps

• Six Degrees of Separation theory explanation: [04:00–07:00]
• Milgram’s Small World Experiment: [07:00–12:00]
• Advances in Network Science: [14:00–16:00]
• Social Media & Empirical Networks: [17:00–18:15]
• Kevin Bacon Game—Origins: [18:15–21:00]
• How Bacon Numbers are calculated: [21:00–25:00]
• Gary’s personal Bacon Number: [26:47–28:30]
• Is Bacon the acting universe’s center?: [29:00–30:00]
• Erdős and Bacon-Erdős Numbers: [31:30–34:00]
• Morphy Number and Apostolic Succession: [35:30–37:30]
• Closing reflection: [38:30]

Conclusion

Gary Arndt’s episode provides both a concise history and a broad cultural survey of the “six degrees” idea. He unpacks its scientific origins, the fun (and math) behind interconnectedness, the pop culture game that brought it into daily consciousness, and how this way of thinking pervades even academic and religious contexts. The result is a fascinating, accessible look at how surprisingly small and interconnected our world (and social networks) truly are.