What does it mean to “live in a simulation”? If I created a sentient computer program that has no contact with the outside world then you would say it’s living in a simulation, but if you took that same exact program and connected it to a robot you’d say it’s living in reality. But what’s the line? If you add a tiny glimpse of reality but 99.9% of its experiences are stimulated is it living in a simulation or reality? It’s not necessarily a black or white thing but more like a spectrum. In that sense you could say that our brains are creating a simulation of the outside world based on real inputs, but our perception of reality is not necessarily accurate. I would say our brains are on the spectrum of being a simulation of reality because not everything we experience is necessarily real.