'mUrti' is not just an idol. mUrta is that which has settled into a form or shape. mUrti means embodiment or manifestation of something.
When scultpors carve or painters paint or we create, idol is created. prAna prathistha is the process by which we make the idol into an embodiment or manifestation or mUrti of a divinity.
Unless an idol or picture has gone through prAna prathisthA it is not an embodiment or manifestation. In all pUjas, we do prAna prathisthA to make that idol or picture into an embodiment or manifestation.
For eg. in Ganapati pUja, we invoke the Ganapati in the Idol. In Sarasvati Puja we invoke the sarasvati in the idol. We make the idols/pictures embodiment or manifestation of the divinity that we invoke.
if we believe 'aham brahma -asmi', that we have the brahman/evolution in us, we are giving that evolutionary power to the idol and
make it an embodiment of a divinity that we are invoking. That's the concept.
The steps of prAna prathisthA are
1. RSayadi nyAsa
2. Kara nyAsa
3. hrdayAdi nyAsa
4. dhyAna mantra
5. prAna prathisthA mantra
What does brahman, the evolution do..? It invokes the originators of Universe, Brahma, Vishnu, Maheswara (which I translate as spacetime, mass, energy). From them it invokes the Rk, Yaju, sAma (which I translate as quantum, classical and biological). This invocation when done by us on the idol, by reciting the mantras is called RSyAdi nyAsa.
Then comes Kara nyAsa. It appears at the outset as certain hand gestures through which energy is given to the idol. But I see it this way.
Brahman, the evolution progresses the biological evolution through evolution of chemical messenger/signaling system that regulates biological functioning. In humans it is through endocrine system. Our hands (notably the digit ratio) represents the influences of pre-natal endocrine. Hence we use the fingers of our hand to symbolically evolve that chemical messenger system in the idol. That is the kara nyAsa.
Then comes hrdyAdi nyAsa. Again it appears as if we are invoking energy in the idol through our heart, brain and other parts of our body. But I see it this way.
There are different organ systems for a living body. They are central and peripheral nervous (siras and shikha), circulatory (hrdaya), integumentary (kavasa), respiration, digestion, excretion (tri-netra) and locomotor (astra). We symbolically invoke these organ systems in the idol to make it a living body. This is the hrdyAdi nyAsa.
Then comes the pancha-prAna dhyAna mantra. Here panch-prAna is visualized as one 'devi' (the property of the idol) present in five different organ systems, with five weapons and three eyes. This pancha-prAna devi is invoked in the idol.
The five organ systems invoked are 1. raktam bodhi sta (awakened in the blood, circulatory) 2. poTa ullas (excretory) 3. sad aruNa (seated in digestive fire) 4. sarah ja (born in the movement, respiratory) 5. adhiruda karabjai (in the brain, nervous system). The three eyes by which she is recognized are sRsti, sthithi and samhAra. This pancha-prAna in us is meditated upon or invoked in the idol as prAna shakti that comes into the idol from us.
Then comes the prAna prathista mantra. This is in the form of 10 sounds followed by words 'Hamsa soham soham Hamsa". Then we invoke the ten indriyas in the idol and say life (jiva) has come into this idol making it a mUrthi, the embodiment. Then we pray to this mUrti and give some offerings to the mUrti.
I see it this way. Following the chemical messenger system, the other organ systems being invoked in the idol, the five core functions are meditated upon and invoked in the idol, we invoke the ten indriyas (as in us) in the idol with ten different sounds. Then we recite aHam sa sa aham; sa aham aHam sa. This invokes the 'self' (aham) in us in the idol.
The aham in us is the Brahman, the evolution. We invoke this Brahman in us, in the idol, which already has all biological functions and the indriyas. This invocation of aham sa sa aham in the idol invokes the brahman, gives it the 'jiva', the life. Thus the idol has become a mUrti, the embodiment of the devata.
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The process above is not 'creating' Brahman. It is invoking the Brahman in the idol through a set of procedures which make the idol similar to a biological being with brahman in it. One may believe or not believe in the process. The process itself is logical, but is based on one's faith.
-TBT