Q: Is this the dream phase and what we are dreaming is actually the waking phase?
A: The dream phase is the personal mind dreaming - all the worlds and characters in your dream are products of your own (unconscious) mind.
The waking phase is a collective dream - all personal minds share the same relative reality.
Both the waking phase and the dream phase appear in Consciousness, which is the Absolute Reality of all objective experience.
Q: But isn't the world of plurality, although it exists only within one's own mind, experienced as solid and substantial - outside the experiencer?
A: In dreams, the world of plurality seems to be experienced as solid and outside the experiencer, but in fact it is all happening in the dreamer's mind, which is itself appearing in Consciousness.
Similarly, in the waking state the world appears to be solid, but after exploring the experiencer it becomes clear that it is not the body/mind that experiences a physical outside world, but rather Consciousness experiencing all body/minds and the world within Itself. As such, nothing is outside the True Experiencer - Consciousness.
Q: Is Consciousness really the experiencer? When we analyze an 'experience', we can certainly understand that in order to produce an experience, there must be an experiencer and the experienced with a relationship between the two, called the 'experiencing'. The experiencer of the circumstances in our life , certainly, is not an unintelligent physical body but an intelligent agent - the mind. We can say that no experience is possible in the absence of a conscious principle. Inert matter cannot experience!
A: Isn't Consciousness both the experiencer and the experienced, i.e. experiencing? You seem to imply that the mind is conscious, but when explored the mind is just a stream of thoughts known by Consciousness. That is not to say that there is no intelligence behind the unfolding of the body/mind. On the contrary, on a relative level all body/minds are evolving towards the understanding that their Source is a shared Consciousness.
Q: Yes, the mind is only a good conductor of Consciousness. As written in Sri Adi Sankaracarya's "Atmabodha":
"Just as a lamp illumines a jar or a pot , so also Consciousness illumines the mind and the sense organs , etc . These material-objects by themselves cannot illumine themselves because they are inert".
A: Yes, the mind itself is an inert material object, and therefore cannot experience.