The periodic back and forth movement of a pendulum can be modelled as a circular rotation with constant angular velocity. We "know" that it just goes over and b

The periodic back and forth movement of a pendulum can be modelled as a circular rotation with constant angular velocity. We "know" that it just goes over and back so we "know" that the circular motion is just a model. All the same, maybe in the future, they'll figure out that pendulums actually move in 4 dimensions. Then they'll look back at us and think "surely they should have known that pendulums really moved in 4 dimensional circles, because they knew about this model". I'd imagine it's similar looking at the sky. If you "knew" the motion of the planets was related to some Gods moving around, you might expect that circular motion was just a model there too.