The theory or belief that reality is a simulation to a degree that it isindistinguishable from "true reality" and where the inhabitants of the simulation are unaware that they are living in a simulation.
"What if we are living in a simulation, what if none of this is real?"
"What is real? How do you define 'real'? If you're talking about what you can feel, what you can smell, what you can taste and see, then 'real' is simply electrical signals interpreted by your brain." - Morpheus
An engineering activity, where a system is simulated using software that encourages repeated iterations of the simulation. The simulation activity is its own reward, and may never result in a completed design.
Hey, are you ever going to finish that project, or are you just going to keep simulbating it? I'm tired of this endless simulbation, just finish the design!