According to the traditions of Hinduism, out of which yoga took form, we exist in one of three states of consciousness at all times. The objective reality we all share and try to agree upon is the first state of awareness, its called jagrat. This waking state is identified with the limited concerns of the ego and its particular time and space. While in the jagrat state we are drowning in that which we seek, deluded by the very fabric of experience. Once asleep we begin to dream and enter the second state of consciousness called swapa. In dreams we continue to delude ourselves through attachments the ego has to the world, however, our experience becomes ours alone. The subjective nature of swapa can result in time and space becoming vague or warped. Beyond dreams we enter a deep state of awareness called sushupti. As we pass into unconsciousness we loose all identification with the ego and thus all reference to time and space slips away. While in sushupti, we flow into the eternal nature of the universe...then the alarm goes off, we hit the snooze button and the whole process starts anew. You might liken yoga to the lenses in eyeglasses. Yoga focuses or intensifies the energies of our life, thereby clarifying our attachments. With sustained practice yoga can take us to the fourth state of consciousness called turiya. Here we wake up to the eternal nature of the universe and begin to experience the bliss of samadhi moving beyond attachment.
Interestingly, the various states of awareness are part and parcel of the symbol and sound of Om (AUM). A represents jagrat, U invokes swapa, M symbolizes sushupti and the resonating vibration turiya. By chanting Om we make audible the very thing we seek.