Q: How is it that Pranayama develops mental capacities? What part does it play in bringing about the higher consciousness?
It is the Pranic vital-currents which sustain mental activity. When these currents are changed by Pranayama, they bring about a change in the brain. The cause of dullness of the brain is some obstruction in it which does not allow the higher thought to be communicated to it. When this obstruction is removed the higher mental being is able to communicate its action easily to the brain. When the higher consciousness is attained the brain does not become dull. My experience is that it becomes illumined.
All the exercises, like breathing-practices, are only devices which something that is behind them is using for manifesting itself.
On the physical plane also, it is nothing else but certain devices — a system of notation — that we employ. But we give too much importance to the form of the device, because we think the physical to be the most real. If we only knew that the entire physical world is made up of force and that it is nothing else but the working of a certain consciousness and power using certain devices then we would not be deceived.
– Sri Aurobindo