Excerpted from From Teaching Yoga, Chapter 4, "Subtle Energy"

In Chapter One we saw how the rise and spread of tantra eventually gave rise to Hatha yoga as a practice of conscious embodiment. Rather than starting with meditation or other practices, the original Hatha yogis worked with the immediate experience of their physical bodies to move through the layers of being that seemed to separate their sense of individual being, including body and mind, from connection with all of nature or the divine. Drawing from the deep well of ancient wisdom found in the Upanishads and a wide variety of esoteric traditions handed down through ritual, songs, and stories, they undertook this exploration with an expanding map of consciousness and being that today still gives us the primary concepts of anatomy and physiology from a traditional yogic perspective.

For many these concepts are treated literally, while others view and use them in practice and teaching as symbolic ideas that help chart t...