Thinking about redefinitions of the Buddhist notion of Emptiness or Sunyata:
The space in which thoughts arise.
The container of the thought stream.
Where the container also has predictable structural elements and tendencies.
These structural elements are given by the psychograph, modeled partially by personality systems (i.e. Enneagram ego typology) and developmental psychology (i.e. Cook-Grueter’s Ego Development Stages).
This container is the space in which thoughts arise.
You are not your thoughts.
You are not your thought stream.
Anything you can witness is not You (if You are the subject).
Because anything you can see is an object, therefore not the subject.
You are the Witness.
Though I will assert you are more (though not wholly) the container than the Spiritual traditions care to admit…as the much of the features of the witness is given by the container.
All for now.