Whenever anything objective appears, there is a subject.
Looking at our own thoughts and mental activities is no different; what we see is objective. What we don’t see is the subject.
We witness phenomena appearing, interacting, transforming and disappearing, whether they are so-called external material phenomena or internal mental phenomena. All are objects for an invisible subject.
What is thus witnessed (not merely visual of course, but also tactile, audible, olfactory), the patterns of phenomenal change, is termed in Buddhism as dependent-origination. It could also be termed as simply, the world, or the universe, or existence.
What witnesses this dependent-origination, the ungraspable subject, the ultimate subjectivity (the ground of that empirical self we assume ordinarily to be our ‘selves’) is not, is never, separate from the objectified world of dependent-origination.
The objective depends on the subject, the subjective depends on the object. This is the nature of conditioned existence; dependent-origination-witnessing-itself.
Whether we term the phenomena mental or material, consciousness or concrete, the reality is the same; appearance only, perception only, phenomenon only.
This reality is of a great creative dynamism, a presentation like a dream unfolding.
Whether the dreamer be called God, or Brahma, or Atma, or the Storehouse Consciousness, or Being, or Emptiness, the ultimate unconditioned reality of this dream called the world is of one nature; that it is so, or to use the Sanskrit, tathata.