September 25th, 2021

> Since the world we experience is the world of perception, it
usually makes little difference whether we say we’re controlling perceptions or controlling the state of the real world. It does, however, make a difference when we try to explain behavior in terms of some physical model of a behaving system.

> The two problems go together: the problem of reaching agreement with each other about reality, and the problem that all perception is fundamentally private. If our perceptions were not private, we would never disagree with each other about the world and its meanings. If they were not, somehow, similar, we wouldn't be able to tell jokes or communicate about anything. It is, of course, possible that our perceptions are both private and similar.