Consciousness is the facility for awareness: the ability to be aware and perceive. There are nominally 7 states of consciousness. In the waking state, there are 4 levels of consciousness.
“The ultimate value of life depends upon awareness.” ~ Aristotle
The 4 nominal states of human consciousness are awake, asleep, dreaming, and transcendence. The first 3 you are doubtlessly familiar with.
The 4th state of consciousness – transcendence – exhibits as mental silence. For most people, transcendence is fleeting when it does occur. Transcendence may transpire when the mind-body has become fatigued and the mind-body system momentarily lapses into relaxation.
In the transcendental state, the mind rests as consciousness communes with Ĉonsciousness. Ĉonsciousness is the unified field which localizes into a consciousness for each life form, from biomolecules such as proteins to cells and organisms. That all localized consciousnesses emanate from a unitary Ĉonsciousness is how the illusion of an objective Nature is obtained. (Nature is the exhibition of existence. Existence is all that may manifest.)
Habituating your mind-body to transcendence facilitates elevating the waking state of consciousness to a higher level. The 3 elevated states of consciousness are enlightenment (quiet consciousness, quietude), coherence consciousness, and realization (unity consciousness). These higher levels correspond with tightness of coupling to Ĉonsciousness.
An organism may be in multiple states of consciousness simultaneously. Dolphins are known to sleep, perchance dream, while still awake. Enlightenment is essentially sustained transcendence while awake.
Enlightenment is the 5th state of consciousness. Quiet consciousness is a distinct level above merely being awake, with nattermind as a frequent nuisance. In quietude there is intrinsic contentment. Bliss is part of the reward system Ĉonsciousness provides for those in the quiet consciousness state.
The practice of meditation is aimed at attaining quietude. Enlightenment is the first step of living in meditation.
Coherence consciousness is the 6th state of consciousness. Coherence consciousness is characterized by awareness of the unity of Nature. Those who speak of “peak experiences” are referring to moments in coherence consciousness.
Realization is a unification of consciousness with Ĉonsciousness. Obviously, the localized mind-body system intrudes on what is otherwise an indescribable experience of rich perception and intuition.
For more about Ĉonsciousness and why Nature is formulated as it is, read Clarity: The Path Inside. The podcast show Reality & Realization is a complement to Clarity. The 2nd episode of that show is on states of consciousness (repetition, yes; this entry is more concise).
Ishi Nobu, Clarity: The Path Inside, BookBaby (2019).
Ishi Nobu, Unraveling Reality: Behind the Veil of Existence, BookBaby (2019).
Ishi Nobu, Spokes 5: The Echoes of the Mind, BookBaby (2019).
Ishi Nobu, Spokes 8: The Hub of Being, BookBaby (2019).
Joseph Castro, “How do dolphins sleep?,” Live Science (14 April 2014).
“Dolphins stay awake for 15 days by sleeping with one half of brain,” The Telegraph (18 October 2012).