Sri Aurobindo translates Prashna Upanishad, Fourth Question, Verses 5-6: “Now the Mind in dream revelleth in the glory of his imaginings. All that it has seen it seemeth to see over again, and of all that it hath heard it repeateth the hearing: yea, all that it hath felt and thought and known in many lands and in various regions, these it liveth over again in its dreaming. What it hath seen and what it hath not seen, what it hath heard and what it hath not heard, what it hath known and what it hath not known, what is and what is not, all, all it seeth: for the Mind is the Universe. But when he is overwhelmed with light, then Mind, the God, dreameth no longer: then in this body he hath felicity.”
There are different types of dreams. Some of them represent sensory and life experiences from the waking consciousness that are being regurgitated and processed by the subconscious mind once the focus and control of the waking consciousness have been suppressed through sleep. These may be snippets of experience thrown together in a somewhat chaotic fashion, or they may present themselves in what appears to be an organised manner. Other dreams go beyond the actual experience of the dreamer in the waking world, to let the mind range free beyond its normal boundaries of ego: as the Upanishad notes “the Mind is the Universe.”
Western dream researchers, such as Freud and Jung, described multiple types of dreams as well. C. G. Jung, in particular, considered dreams to open the door to the “collective unconscious”, providing access to virtually everything in the universe. This would agree well with the Upanishadic statement.
The nature of consciousness is One and Universal. When the mind is freed from the shackles of the ego-consciousness, it has access to the universal consciousness and can range everywhere. This experience is one that can take place in the dream state and this brings forth knowledge about people, places, things, and events about which the waking consciousness has no specific knowledge. Problem-solving can take place in this state as well. This is also the basis of various forms of prophetic dreams.
Beyond the dream state there is a state of concentrated light and power. The term used here tejas, has been translated elsewhere as “light and power” by Sri Aurobindo. This experience of a mass of light can overwhelm the mind and it no longer is triggered to jump but is drawn in, concentrated and illuminated. This is a state of bliss where the mind no longer seeks anything, but basks in the radiance of the One.
Sri Aurobindo, The Upanishads, Prashna Upanishad, pp.297-315