The Diary Of A CEO with Steven Bartlett
The Diary Of A CEO with Steven Bartlett

Top Scientist REVEALS: A Kid In The 29th Century Could Have Made This World! | Prof Brian Greene

August 17, 2026

AI Summary

5 min read

The Universe in a Brief Crack of Light

“I can't convince you that we're not in the Matrix. Why? We could be.” That is how physicist Brian Greene opens his conversation with Steven Bartlett—not as a provocation, but as a logical starting point. A kid in the 29th century, fiddling with a simulation program in their garage, could have created the world you and I experience as real. Greene is not being glib. He is working from the premise that consciousness could, in principle, be generated inside a computer, and that if it can, then simulated realities would vastly outnumber the single physical universe—making it statistically likely that we are living in one right now. But he parks that possibility aside. Even if true, he says, it changes nothing: “I'm gonna live out my life in this simulation to the fullest.”

The Fundamental Question and String Theory

Greene’s ultimate question is deceptively simple: What is the true nature of reality? He has spent decades pursuing an answer through string theory, which proposes that if you could look deeply enough inside any particle—an electron, a quark—you would find a tiny vibrating filament. Different vibrations produce different particles, much like different vibrations of a violin string produce different musical notes. A string vibrating one way yields an electron; another way yields a quark.

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What you'll learn

  • 1 (00:03) **Episode Introduction & Ad Break** - Opening ad for T. Row Price, followed by host Steven Bartlett introducing the core philosophical questions of the episode.
  • 2 (03:07) **Greene's Journey & String Theory Explained** - Brian Greene outlines his academic path and provides a clear, accessible explanation of string theory.
  • 3 (07:02) **The Evidence for Strings & The Origin of Energy** - Greene discusses the lack of direct evidence for string theory and traces the energy of the Big Bang through the formation of life.
  • 4 (12:08) **The Simulation Argument & The Nature of Reality** - Greene explores the logical possibility that we live in a simulation and how he chooses to function despite this uncertainty.
  • 5 (15:42) **Consciousness, AI, and the Reality of Emotion** - Greene argues that consciousness is a physical process and that future AI could be conscious, reducing human emotion to electrical impulses.
  • 6 (21:44) **AI, Control, and Evolution** - Greene discusses the risk of losing control to AI but suggests a future of human-AI blending rather than a hostile takeover.
  • 7 (25:56) **The Possibility of Living Forever** - Greene argues that death is not inevitable and that extending human life by hundreds of years is within the realm of possibility.

+ Full timestamped outline available in the app

Guests on this episode

Brian Greene Steven Bartlett

Show Notes

Professor Brian Greene reveals the biggest questions science still can’t answer, whether we’re living in a simulation, why AI may deserve human rights, and what happens at the end of the universe! 

Professor Brian Greene is a theoretical physicist, mathematician, and Professor of Physics and Mathematics at Columbia University, where he also directs the Center for Theoretical Physics. He is a leading researcher in string theory, the co-founder of the World Science Festival, and the bestselling author of several books, including ‘Until the End of Time: Mind, Matter, and Our Search for Meaning in an Evolving Universe’. 


He explains:
◼ Why most physicists believe time travel into the future is already possible
◼ Why he believes humans don't actually have free will
◼ How string theory could reveal what everything in the universe is really made of
◼ Why the "Pale Blue Dot" changes how you see your own life and problems
◼ Why the search for meaning may matter more than finding the answer itself

Chapters

  • 00:00:00 Intro
  • 00:02:22 The Big Question Science Is Trying to Answer
  • 00:03:49 How String Theory Could Explain Our Universe
  • 00:04:44 How Could We Ever Prove String Theory Is Real?
  • 00:06:17 What Makes the Strings in String Theory Vibrate?
  • 00:07:52 Can String Theory Explain Why We’re Here?
  • 00:09:16 What If We’re Living in a Simulation?
  • 00:11:23 How Can Physics Explain Human Emotions?
  • 00:17:23 Could Humans One Day Manufacture Emotions?
  • 00:18:53 Would Knowing We’re in a Simulation Change Anything?
  • 00:20:24 Could Humans and AI Eventually Merge?
  • 00:20:59 Could Humans Ever Achieve Immortality?
  • 00:24:57 How Knowing We’ll Die Shapes Every Decision We Make
  • 00:26:59 Why Are We Here? The Optimistic and Pessimistic Answers
  • 00:30:24 How Did Gods and Religions First Emerge?
  • 00:33:33 What’s the Most Compelling Case for a God?
  • 00:36:41 How Can We Comprehend Billions of Years?
  • 00:40:12 Does Our Place in the Universe Make Us Insignificant?
  • 00:42:48 How Big Is the Observable Universe, Really?
  • 00:46:59 What Exists Beyond the Observable Universe?
  • 00:47:56 Why Are Humans So Obsessed With Aliens?
  • 00:51:45 Ads
  • 00:54:26 What Is the Meaning of Life?
  • 00:56:26 Is Free Will Actually Real?
  • 01:00:41 What If Consciousness Is the Foundation of Reality?
  • 01:08:
The Diary Of A CEO with Steven Bartlett

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