Although I am not qualitifed, will try to summarize, pls correct
me if my understanding is wrong.
Our knowledge about the world through our senses gives rise to
attachment about inherent existence in everything. We are not able
to observe subtle changes and the relationship of all things
directly although we may be educated about inter-dependencies of
all things.
We always feel that our mind is separated from the outside
world. We see, hear, reflect ... but we always conclude that the
outside world is separated from our mind. This is a fundamental
mistake.
When we are englightened, there is no observer nor the observed.
However, there are different levels of enlightenment. For certain
Theravadic sage, his experience about the world is quite similar to
normal people like us although he will not attach to anything.
It is similar for entry-level Mahayana sages, when they are in
samadhi comtemplating on emptiness, they do not experience worldly
view. But when they are out of samadhi, the experience is back to
normal.
Another breakthrough is achieved when it comes to 五地菩薩 (the
fifth ground level bodhisattvas). They are able to unify both
emptiness and the arising phenomenons within samadhi. (form is
emptiness, emptiness is form ?)
For the eight ground level bodhisattvas and above, they are able
to achieve it effortlessly.