Nested Sims

simthesis.org 3 min read

Nested Simulations take the simulation hypothesis one step further — what if simulations can exist inside other simulations? Like Russian nesting dolls (Matryoshka dolls), one simulated reality could contain entire civilizations that then create their own deeper simulations.

Think of it like this: You’re playing a video game, and inside that game the characters build their own video game. Those characters then build yet another game inside theirs. Each layer feels completely real to the beings living inside it.

The Core Idea

In a nested simulation, there is no obvious “base reality” at the bottom. Advanced civilizations in one level could run countless ancestor or other simulations, which in turn run even more simulations. This creates an almost infinite stack of realities, each one computationally generated by the level above it.

The idea builds naturally on Nick Bostrom’s ancestor simulation argument. If a simulated civilization reaches the technological level needed to run its own detailed simulations, there’s no reason it couldn’t create nested layers — potentially leading to vast numbers of simulated minds across many levels.

How Nesting Changes Things

Nesting makes the probability question even more striking. If each simulated civilization runs many simulations of its own, the total number of conscious beings living in deeper layers could be astronomically larger than those in the original base reality. This means most conscious experiences would likely occur deep inside multiple nested simulations rather than at the top level.

From inside any given layer, everything would still feel perfectly real. Physics, emotions, and daily life would operate normally — unless the simulators introduced glitches or limitations between layers.

Challenges and Implications

Nested simulations raise mind-bending questions: How deep could the stack go? Could we detect signs of nesting, such as limits in computational resources or inconsistencies in physics? And if reality is nested, does the idea of a single “true” base reality even make sense anymore?

Some thinkers suggest that nesting could explain strange features of our universe, such as the apparent fine-tuning of physical constants or the strange behavior of quantum mechanics.

What Makes It Exciting

Nested Sims push the simulation hypothesis into even more fascinating territory. They show how one simple idea can scale into something vast and layered. As our own technology advances toward creating convincing virtual worlds, the possibility of nested realities feels increasingly plausible — and increasingly mind-expanding.

Exploring nested simulations opens the door to other theory types, including dream/consciousness-based models and purely mathematical universes.

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