There are four basic states of consciousness.
The first level corresponds to the sleep of the consciousness, which is a very deep, unconscious level without any self-awareness. The physical body can be very active in this state. We are talking about the sleep of consciousness, not the body. The first state of consciousness is called Eikasia in Greek. Plato used this term to describe human imagination that perceives fantasy or that which is illusory. Eikasia is perception of illusion taken as reality.
The second level is the sleep of the consciousness with dreams, which means the consciousness has perception of imagery, of phenomena, but without self-consciousness or self-awareness. Again, this is a state of consciousness, not a state of physical inactivity. The body can be active or not. The second state of consciousness is Pistis in Greek.
The third state of consciousness is self-awarenes with conscious / objective revision of subjective mental formations (thoughts, feelings, sensations). It is a conscious form of reasoning that seeks to transcend subjective reasoning. In Greek, it is called Dianoia.
The fourth state is called in Sanskrit "Turiya," which means pure consciousness free of defilement, without any subjectivity at all. In Greek, it is called "Nous." This is a state of consciousness that has perfect, objective perception. Nous in Greek means intellect or reasoning, but it is pure objective reasoning without any obscuration at all. In other words, those who have acquired this state of consciousness have no pride, lust, anger, envy, fear; they have no ego. Turiya is a capacity of the inner Being. Turiya is the state of consciousness acquired by beings such as Jesus, Buddha, Krishna, and Moses. In other words, common people are very far from this state.
When we understand these four steps and begin to look at ourselves to acquire the self-knowledge that is the basis of Gnosis, it becomes evident that we really do not know anything experiential about the third and fourth states of consciousness. It becomes clear that the vast majority of our time is spent encaged within our subjective perceptions of life. We “see through a glass, darkly.”