Plans need not be coherent or even rational. They need only include a sequence of actions determined in advance. The idea of thinking as simulation is consistent with my original conception, and extends it in a useful direction. An idea can be tried out as a linguistic string and fed back into the perceptual mechanisms of the brain, completing a serial loop through neurological machinery originally evolved to deal with the outside world. By a process of successive iterations, plans can thus be refined without having to try them out in the real world.
Language greatly extends the range of possible simulations.
The simulation language can be used to unify several psychological processes that seem qualitatively distinct. Simulation of the future is generation of new plans, and simulation of the present is awareness. The only things going in and out are tiny depolarizations on millions of parallel axons. Somehow the brain translates these into a reality, a sense of being in the present time and place. We are always the willing victims of an illusion of virtual reality.