Top Scientist REVEALS: A Kid In The 29th Century Could Have Made This World! | Prof Brian Greene
with Prof Brian Greene
17 Aug 20264 min read38m
TL;DR
Physicist Brian Greene argues we cannot rule out that reality is a computer simulation run by a future civilisation, because if consciousness can be created artificially — which Greene thinks is likely — simulated beings will vastly outnumber real ones, making it statistically probable we are already in one. He also contends that all human emotion, including love and grief, reduces to electrical impulses in the brain, and that our evolutionary future likely involves merging with AI rather than being replaced by it. String theory, meanwhile, remains mathematically compelling but experimentally unverifiable with current technology.
Key Moments
Brian Greene
“I can't convince myself and certainly I can't convince you that we're not in the matrix. Why? We could be.”
Greene explains why the simulation hypothesis cannot be logically ruled out, even for a scientist
“Maybe there's a kid in, you know, 29th century Earth who's in his or her garage right now and they came up this wonderful computer program and they're simulating historical episodes in the past and they happen to allow you and I to exist sitting at this table.”
Greene illustrates the simulation argument with a vivid, concrete scenario of a future teenager running our reality as a hobby project
“If we're in a simulation and all we're doing is figuring out the laws that the 15-year-old futuristic kid decided to impose on this artificial world, hey, that's not a bad way to spend your time, too.”
Greene reflects on what the simulation hypothesis would mean for his life's work as a physicist
“We can use the math of quantum mechanics to predict the strength of that magnetic field and it comes out 2 point blah 15 decimal places long. We can do the math. We then can measure the magnetic field and it agrees digit by digit by digit by digit by digit with what we calculate.”
Greene cites the electron magnetic moment as breathtaking empirical evidence that deep mathematical patterns govern reality
Brian Greene is a theoretical physicist and professor at Columbia University, where he serves as Director of the Center for Theoretical Physics. He grew up near the Hayden Planetarium in Manhattan, studied mathematics and physics at Harvard, and earned his doctorate at Oxford working on string theory. Greene is one of the world's leading advocates for making complex physics accessible to general audiences, known for his books and public science communication.
Takeaways
1
Quantum mechanics predicts reality to 15 decimal places The electron's magnetic moment, calculated using quantum mechanics, matches experimental measurement digit-for-digit to 15 decimal places. Greene treats this as near-miraculous evidence that the universe has deep, discoverable mathematical structure — and that a brain evolved to hunt bison somehow stumbled onto equations that describe reality with extraordinary precision.
2
Longer lifespans won't change our existential psychology Greene argues that even if medicine extends life to 500 years, humans at age 475 will feel the same mortality anxiety we feel at 75 — the dread just shifts along the timeline. He credits Ernest Becker's 'The Denial of Death' for the insight that awareness of mortality drives most human behaviour, a framework that survives any extension of lifespan short of true immortality.
3
Simulation hypothesis is statistically hard to dismiss Philosopher Nick Bostrom's argument, endorsed by Greene, holds that if future civilisations can run conscious simulations of their ancestors — and Greene thinks they can — they will run billions of them. That means any conscious being is statistically far more likely to be simulated than real. Greene's honest verdict: he can't disprove it, so he parks the thought and moves on.
4
All emotion is electrical signals — consciousness may be substrate-independent Greene holds that love, grief, anxiety, and every other human emotion are ultimately electrical impulses in neurons, not something mystical. If that's true, silicon circuits running equivalent impulses would be equally conscious. This has direct implications for AI rights and for the simulation argument: once you accept substrate-independence, the barrier to artificial sentience disappears.
5
AI and humans will likely merge, not fight Rather than the binary of 'humans in control vs AI takes over,' Greene predicts a gradual blending where the line between biological and artificial intelligence dissolves. He points to an 80-year-old mathematical conjecture (the Jacobian conjecture) recently solved with AI assistance as an early signal of this partnership. The result may be a new life form that can no longer be called human — and Greene is fine with that.
6
String theory is mathematically compelling but untestable today Greene explains that string theory's credibility rests entirely on mathematics — specifically that the equations of quantum mechanics and general relativity fit harmoniously inside string theory's framework. No particle accelerator yet built can probe the energy scales needed to observe strings directly. The theory could be 'utter nonsense' by Greene's own admission, but the math keeps pointing there.
7
Religion functions as existential anxiety management, not science Greene distinguishes religion from science by purpose: science tries to explain how the world works; religion evolved to manage our fear of death. He points to archaeological evidence of elaborate grave goods — taking individual artisans years to craft — as proof that our earliest ancestors were already constructing narratives about life after death. He sees this as a wondrous human creation, not an enemy of science.