Plato and simulation
Plato believed that the material world was merely a shadow of the world of ideas.
He believed that a beautiful painting is beautiful because it participates in the idea of Beauty, that a just action is just because it participates in the idea of Justice, and that two things are equal because they are related to the idea of Equality.
In this way, the world of ideas functions like computer code, and the material world like the execution of that code.
Plato also believed that the material world was made of geometric figures, and that geometric figures were made of triangles.
This is very similar to three-dimensional video games, because all the figures are made of triangles.
Therefore, Plato's Theory of ideas can be seen as an early precursor to a computational theory of reality