philosophy
What are the three states of consciousness and what does turiya, the fourth state, represent?
What the tradition says
The Mandukya Upanishad looks closely at our own experience and finds three common states. The first is waking, called jagrat, when we are awake and aware of the outer world. The second is dreaming, called svapna, when the mind makes its own world while the body rests. The third is deep sleep, called sushupti, where there are no dreams and no sense of self, only a quiet rest. The tradition links these three to the sound AUM: A for waking, U for dream, M for deep sleep. Then it points to a fourth state, turiya, which simply means "the fourth." It is not another experience added to the list. It is the still awareness that is present in all three. The Upanishad describes it as the silence after AUM, the witness behind everything that comes and goes.
What turiya represents
Turiya stands for pure consciousness, the part of us that does not change while everything else does. In waking, dream, and sleep, the contents keep shifting, but something is aware through all of them. That witnessing awareness is what turiya names. In this view, it is seen as the true self, calm and untouched by the rise and fall of thoughts and states. Because it is beyond words and beyond ordinary experience, the texts often describe it by saying what it is not, rather than by defining it directly.
Where this teaching comes from
The clearest source for this idea is the Mandukya Upanishad, one of the short and important Upanishads. A later thinker named Gaudapada wrote a commentary on it, often called the Mandukya Karika, which expanded these ideas and shaped how the Vedanta tradition understood them. Different teachers and schools have read these states in their own ways, so the details and emphasis can vary.
Why people still study it
Many people today find this a simple and direct map of the mind, drawn from things everyone knows: being awake, dreaming, and sleeping. It is widely discussed in books on meditation and Vedanta. Some explore turiya through quiet practice, while others read it mainly as philosophy. There is no single way it is understood, and it remains a topic people return to with curiosity.