Sri Aurobindo describes different types of dreams which should be distinguished so we can make sense of what the dream state is all about.
“Normally it is a subconscient part in us, intermediate between consciousness and pure inconscience, that sends up through this surface layer its formations in the shape of dreams, constructions marked by an apparent inconsequence and incoherence.”
Some are random bits and pieces of current daily life events, while others are pieces of memories triggered from the cells. Some dreams, while apparently phantasms or unconnected to our waking life, are actually symbolic structures trying to deliver meaning to us from either deep psychological drives that we have internalized in our lives, or even from archetypes of what C.G. Jung has described as the “collective unconscious”.
Dreams arising from the subconscious also may try to re-establish or re-enact actions or ideas that we have rejected in our waking consciousness, with the hope that what our waking awareness has thrown away, our subconscious self may accept. We begin to see that all thoughts, actions, impressions have in fact been stored in our subconscious, or in the inconscient parts of our selves, and can be triggered and can then emerge in the dream state.
Once we begin to recognize symbolic or psychological relevance to some dreams, we can no longer discount them as totally meaningless, of course.
While some dreams originate from the subconscious, there are also dreams that arise from the part of us, which can begin to express itself when our surface waking consciousness has temporarily withdrawn, as in sleep. This subliminal part can be in touch with not only the unconscious, but deeper occult levels that are connected as well to higher forces trying to manifest within our mind, life and body.
reference: Sri Aurobindo, The Life Divine, Book 2, Part I, Chapter 5, The Cosmic Illusion; Mind, Dream and Hallucination, pg. 422