The Universe is made up of gross, subtle and causal matter.The causal Universe is collective primordial nature. In gross form, it is the elemental, uncompounded and unorganized form which, after compounding, becomes organised and gives rise to organic life like herbs, food, human beings, animals, birds etc. The Taitreya Upanishad says that all organs are products of inorganic matter.The elements in subtle and uncompounded form have their qualities called tanmatras which are: sound (space), touch (air), form (fire), taste (water) and smell (earth). The elements when compounded become gross and are predominantly tamasic (lethargic, drowsy) by nature and when infused with life, enter the cycle of births and deaths, which in individual cases takes place in accordance with their past karmas. The gross body is the seat of pleasure and pain. The food that is consumed is converted into three components in the body viz. the gross portion which is thrown out as waste, the middle portion is retained as flesh, blood etc. and the subtle portion operates the mind.
Illusion has three qualities viz., satva, rajo and tamasic. They arise out of agnana (ignorance) and result in sense organs. Satva guna gives birth to gnanendriyas (sense organs of hearing, touch, seeing, tasting, smelling) all of which combine to become Antakarana, the conglomerate of intellect, mind, memory and ego. Rajo guna gives rise to organs of action, karmendriya, the limbs, mouth, generative and excretory organs and Prana (including its five functional parts). It is interesting to note that hands, which are karmendriyas when engaged in action, become gnanendriyas when experiencing sense of touch.
Similarly, the mouth in general and tongue in particular are karmendriyas while engaged in the activity of speaking but become gnanendriyas when the tongue is involved in tasting.This is the subtle body or linga sareera made up of gnanendriyas, karmendriyas, Prana and Antakarana, which is the instrument through which the jiva experiences pleasure and pain. The causal body or the karana sareera is the total ignorance, agnana, which is responsible for the birth of the gross and subtle bodies and represents the tamo guna. Thus the gross body arises from gross elements and the subtle body from the subtle elements. The casual Universe is collective ignorance. It is this ignorance, nescience, or avidya which is responsible for the creation, both individual and collective, and for the cycle of births and deaths and is called illusion (Maya), a power wielded exclusively by God. Maya signifies change or movement which is constant and necessary, as stagnation leads to death.