Krishna tells how Kama operates
dhūmenāvriyate vanhir yathādarśo malena ca
yatholbenāvṛto garbhas tathā tenedam āvṛtam
yatha – just as
vahnih – the fire
dhumena – by clouds of smoke
avriyate – is covered
adarsah – mirror
malena – by dust
ca – and
yatha – just as
garbah – foetus
ulbena – by the womb
avrtah – covered
tatha – so too
tena – by that (binding desire)
idam – this (knowledge)
avrtam – is covered
Just as the fire is covered by clouds of smoke, just as a mirror is covered by dust, and just as a foetus is covered by the womb, so too, knowledge is covered by binding desire.
There are two types of vivekas or buddhi required. – Dharma-adharma viveka and atma-anatma viveka. This two fold is required to conduct your life. If you have dharma adharma viveka, then the atma-anatma viveka will follow naturally. These two vivekas constitute jnana i.e. knowledge.
The mind, buddhi that has this knowledge is covered by Kama, just as fire can be covered by its own smoke. Like fire, jnana is also self-revealing but because it is covered we cannot know it. When Kama comes, it takes over you so completely that your wisdom is lost.
Krishna provides 2 examples here. A mirror covered by a coat of dust and a foetus covered by the womb. The mirror and the foetus are not seen simply because they are covered. You can see the mirror, but at the same time it is not clear i.e. you cannot see your face. Similarly, an unborn child is there, but you cannot see it because it has to yet to the see the light of the day. Of course, modern science shows the foetus growing, but without any such external objects, can we see the foetus? So too, in the first example, we know the fire is there because you see the smoke, but we cannot see the fire as it is engulfed with smoke.
The example of the unborn child shows the time factor as it takes nine months for a child to see the day. This also means that our mind needs time for maturity to understand the subtle things and control the desires. It cannot happen overnight