The Religion and Philosophy of the Veda and Upanishads v2.c40.s9.17

v2.c40.s9.17

In this condition of sleep without dreams it is clear that the older Upaniṣads find the highest bliss,⁴ the complete union of the individual with the absolute,⁵ which is all that can be attained by man. In the later Upaniṣads⁶ there appears the effort to add a fourth condition, called by its numerical designation the Caturtha or more archaically Turīya. This state is that which is attained not in deep sleep, but in the waking condition by the effort of concentration of the mind which is Yoga. The two conditions of deep sleep and the fourth differ, not in point of their failing to recognize plurality, but in the fact that the Turīya knows no slumber: the Turīya is neither deep asleep nor dreaming: