A simple model from traditional sāṁkhya.
An infinity exists - unmanifest. Within are three categories:
1. sattva - illuminating/discriminating/"aware"-ing,
2. rajas - impelling - and,
3. tamas - impeding.
All three are initially unmanifest as well.
sattva is subtlest, rajas gross, tamas grossest, with respect to understanding.
sattva, rajas, and tamas can have individually different levels of vibration or subtlety.
sattva is also related to willpower; subtlest sattva => subtlest intention or will.
The effects of rajas and tamas on mental and physical "stuff" are the same - causing/changing movement or stopping movement. (Movement is eternal, across different levels, so tamas is also temporary vis-a-vis eternity. Thus, even static rocks erode and disappear over millennia.)
When manifestation starts, sattva is maximum, rajas and tamas are minimum or nil.
Manifestation evolves to grosser levels and devolves to subtler levels. (Why manifestation at all is unclear, though there are speculative answers.)
At our current individual state and that of the universe, sattva is minimum, rajas and tamas maximum. Put differently, free-will in the present is minimum; habitual unthinking reaction - fighting/fleeing or freezing - is maximum.
Individual meditation and other spiritual practices increase the ratio of sattva - in this infinity - compared to rajas and tamas.
One view: increasing activity - rajas - reduces the quantity of tamas, and rajas is reduced in turn by increasing sattva.
Another view: sattva is transmuted into rajas and tamas and reversal happens during spiritual/inward practice.
(krodha may be equivalent to rajas and kāma to tamas. Hence Babuji saying they are natural and practically ineradicable.)
rajas and tamas are "mechanical" or "non-conscious". sattva is also non-conscious, but is closest in appearance or function to consciousness. Thus, spiritual practice aims first at increasing sattva to attain or become pure consciousness.
Once the "devolution" reaches pure or maximum sattva, it can only go further through unmanifestation. At this point, even separation or "this and that" awareness are lost.
Individual devolution probably results in only a part of the infinity becoming unmanifest. A universal devolution alone - mahāpraḷaya - can cause total unmanifestation. What if every individual did not devolve? Can universal devolution occur?
Please note all of the above are only regarding prakṛti or pradhāna. Consciousness-energies - puruṣas - are another set of infinities, each one eternally separate from the prakṛti infinity, and untouched by its series of evolution-devolution sequences.
