Karl Popper’s Three Worlds

World 1

the physical world. We can diretly share this but can’t fully perceive it.

World 2

human experience: feelings, emotions, etc. Can’t directly share this. Actions in here change world 1 which changes world 2.

World 3

everything we create in our heads (incl language) and share with other humans.

Everything has to go through the translation layer of World 2.

Related: beetle in box thought experiment.