Subtle or Astral body or Linga Sharira
Subtle or astral body (Linga Sharira) is where lives mind and intellect.
Manomaya and Gyanamaya Kosh and part of pranamaya kosha resides in Astral or Subtle body.
Linga Sharira contains pranamaya kosha, movement of the pranic force directing our physical and mental activities.
This movement happens through nadis or channels, conductors of energy which are controlled by the six chakras.
Vital sheath is a subtler sheath when compared to annamaya kosha.
This is composed of vital energy.
As long as this vital energy exists in the organisms, life continues.
This sheath is responsible for our physiological functions namely breathing, digesting, metabolizing, circulation, endocrinal, neural, skeletal, muscular etc.
The Linga sharira (subtle body) surrounds the Sthula Sharira (physical body) as an aura of energy.
The Nadis (subtle energy channels) exist in this subtle medium through a fine merger into the physical medium.
This is the “vital body” and the prototype and reflection of the physical body.
It comes into existence before the physical body as the latter is built and formed upon and around it and it only fully fades out and dies when the very last remaining particle of the deceased physical body disappears and disintegrates.
In the internal astral body there are counterparts of organs outside.
They are called astral senses.
A yogi hears through astral ears and sees through astral eyes.
Thus he can hear sounds from distant lands, he can see objects in distant localities.
This is called clairvoyance and clairaudience.
When a person dies, his or her gross body (sthula sharira) is burnt.
This being in fact the ‘Antya ishthi’ ([antyeshthi]]) the last sacrifice offered in fire, but the soul cannot quit the gross body without a vehicle of some kind.
This vehicle is the Linga-sharira or subtle body, sometimes described as angustha-matra (of the size of a thumb), invested in which the deceased person remains hovering near the burning ground or crematorium.
It is the vehicle for and of Prana.
The Upanishadic texts reiterate the existence of a purusha (being) of the size of the thumb (angustha matram) enshrined in the interiors of the heart -
"The self (purusha), that is of the size of a thumb (angustha), resides in the cave of the heart.
The self who is the size of a thumb is a light (jyoti) without smoke."
This "being" dwelling inside the heart has been equated with the ‘jiva’ or the ‘self’ which carries the consciousness and a meta-physical body (prakriti), also termed as the karana sharira.
Kathopanishad says “This shining, luminious angustha-matra entity residing in the cave of our heart is “vibhrajate because of which the whole world is illuminated.”
Astral Body’s Lower Mind: This sheath is the also energy of action.
This mental sheath is composed of two qualities, mana (mind) and buddhi (intellect).
Mana is the rational, linear, sequential, thoughtful mind.
Buddhi is the quality of discrimination which comes after knowledge, after the removal or the absence of ignorance.
The former constitutes the manomaya kosha, while the latter is called as the Vijnanamaya Kosha.
Astral Body’s Higher Mind: The Vijnanamaya kosha is the sheath of the intellect (buddhi) and intuitive knowledge/wisdom which gives us the discriminative capability that helps to differentiate between virtues & vice, good & bad, right and wrong, truth & untruth.
It controls the mind, the senses, the fructifying samskaras & all activities of the body.
The ego-driven intellect can lead to actions when it gets co-mingled with the memories and is clouded over by the manas which result in pain and suffering.
Its knowledge is affected by the moods of the mind and other factors.
Through the practices of meditation, regular self-study & enrichment of knowledge through libraries & discourses could lead towards devotion.
Our mind becomes purified and the intellect can then begin to depend more and more on the pure intuitive wisdom rather than be influenced by the ego.
As you begin to experience this aspect of existence, you discover that this sheath is merely an illusion covering over the eternal self.
Hence the self is different from the body, unchanging, ever pure and free from modifications.
Therefore, the self is a witness of the Vijnanamaya Kosha.