Taoist Yoga and Tantra Yoga
If the Taoist tradition is to be credited with an especially detailed study of chi and the meridians, then the Indian Tantric tradition is to be credited with an especially detailed study of special centers within the brain and spine that control the movements of chi which they called chakras.
In Dr. Motoyama's book Theories of the Chakras, he makes an extensive effort to clarify and integrate these two complementary systems.
In addition to controlling the flow of chi in our bodies Tantric Yogis say the chakras are the bridge between physical and spiritual worlds.
Modern Western science believes only a fraction of human mental potential is used. Indian Tantrics would agree and go further to say the chakras are the switches that turn-on this unused potential.
The Tantric theory of evolution is that human beings must re-awaken those Dvme parts of themselves that are slumbering. Just as a seed does not become a flower without several intermediate stages of growth, so also the Human does not become Divine without several intermediate stages of growth.
Speaking very broadly, Tantra suggests there are seven basic stages of mental/spiritual growth and each stage is associated with the awakening of a specific chakra.
These chakras must be awakened before human consciousness can free itself of limited bodily identification and expand to its potential.