Acharya Prashant explains the different states of human consciousness: waking (jagrata), dreaming (swapna), and deep sleep (sushupti). He describes how each state presents a different version of the world, noting that the waking world is often mistakenly taken as the ultimate reality. He points out that even scientific laws like physics are limited to the waking state and disappear during sleep. The speaker emphasizes that these three states are fleeting mental conditions and not the ultimate truth. By understanding the differences between these states and not taking them seriously, one can find themselves in the fourth state, Turiya.