The Depiction Of Maa ChinnaMasta Severing Her Head, Symbolises the transcendence of the individual self. She Guides the devotee Towards the realisation that when the individual realises The Greater Self, The Absolute, There Is True Self’s Realisation, and the ego is dissolved.
In the chandogya upanisad (6.13.1) the son is instructed by his father About The Greater Self. This is a description Of The Essence Illustrated By Nyagrodha Tree.
“Bring here a Fruit of that Nyagrodha Tree. Break the Fruit. What do you see there?”
“These are very small Seeds, venerable sir.”
“Of these, please break one. What do you see?”
“Nothing at all, venerable sir.”
Then he said, “My dear, That Subtle Essence Which you do not perceive, verily, my dear, From That Very Essence This Great Nyagrodha Tree Exists. Believe me, my dear. That Which Is The Subtle Essence, this whole world has for its self. That is true. That Is The Self. That is you.”
The Greater Self Is Never Born; Nor Does It Die at any time. It Sprang From nothing and nothing sprang From It. It Is Unborn, Eternal, Abiding And Primeval.