Acharya Prashant explains the concept of the four states of consciousness, identifying the first three as waking, dreaming, and deep sleep. He clarifies that the fourth state, Turiya, is not a sequential stage but the underlying foundation or truth upon which the other three states exist. While the waking, dreaming, and deep sleep states are mutually exclusive and cannot occur simultaneously, Turiya is present in all of them as their base. He emphasizes that understanding the reality of these three states is the only way to realize the fourth, as there is no direct method to reach it. The speaker distinguishes between ordinary waking consciousness, where the senses are active, and true spiritual awakening, which is synonymous with truth and attention.