Ancestor Sims

What if future civilizations become so technologically advanced that they can recreate entire periods of history, complete with conscious people who believe they are living real lives?

Ancestor simulations are one of the most discussed versions of the simulation hypothesis. They propose that advanced societies could build highly detailed virtual recreations of their past — complete with entire civilizations — in order to study history, sociology, or their own ancestors.

If common, the number of simulated people could vastly outnumber those who ever lived in base reality.

The Core Concept

Philosopher Nick Bostrom popularized this idea in his 2003 paper Are You Living in a Computer Simulation?.

Bostrom argues that if advanced civilizations can run realistic simulations with conscious beings, they might create vast numbers of them, making simulated observers far more numerous than biological ones.

How They Would Work

These simulations could recreate historical environments, physics, biology, and individual experiences in extraordinary detail. Simulated inhabitants would experience their world as completely real, with emotions, relationships, memories, and sensations indistinguishable from base reality.

The Probability Argument

If future civilizations run millions or billions of ancestor simulations, simulated minds would likely vastly outnumber those in original reality. A randomly selected conscious observer would then be statistically more likely to exist inside a simulation than in base reality.

Challenges and Criticisms

The argument assumes that future civilizations will survive long enough, achieve enormous computing power, and choose to run many ancestor simulations. It also raises deep philosophical questions about whether simulations can produce genuine consciousness.

Why They Matter

Driven by rapid advances in AI, virtual reality, and computing power, ancestor simulations encourage deeper reflection on consciousness, the future of technology, and what it means to be human.