I studied vinnana a while and i believe it is very helpful to understand the difference between sense-vinnana’s that establish in the mind, and that do not. Also for this threat.
For sense- vinnana’s to establish there must be some element of engagement, meaning, a certain interest must we awakened subconsciously for the mind to be pulled towards the sense-door. Without this initital engagement, a sense-vinnana cannot establish. Establishes means: it lands, it takes root in the mind, as it were.
You can also see this difference between arising sense-vinnana’s and establising sense-vinnana’s
in real life. We can see things without eye-vinnana to establish. These are the moments that we see but the eye and mind are not caught by what is seen. The moment eye- and mind are caught by what is seen, only then eye-vinnana’s establishes. Now a certain engagement is there between mind and visual. This engagement (caused by anusaya) is a requisite for vinnana to establish (MN28). In practice, if mindful, one will see the differences between eye, ear- mind being caught by something and not. This is never the difference between seeing and being blind, or hearing and being deaf. No, the only difference is…attached or not attached seeing, hearing etc.
If senses-vinnana’s establish in practice that refers a situation in which awareness has now landed upon something sensed, as it were. It has become engaged and in contact with it, leading to or a pleasant, painful or neutral sensation. In fact, established senses-vinnana’s in this way also represent a load to the mind, a burden, and for that reason established vinnana’s and vedana’s, whatever ones, always represent an element of dukkha.
But in fact it is nothing else but awareness, the knowing, pulled towards senses or directing upon the senses, connecting with it. I
Some believe, this is all Buddha describes as mind. No, this is how defiled mind functions.
Awareness does not have to engage with senses and sense-vinnana’s do not have to establish to see, hear, smell etc. That is called a secluded and pure mind. It has not habitual drifts anymore to become engaged with sense-objects. It knows all what appears but does not become engaged.
It does not really matter if one speaks of mind or consciousness or awareneness, the point is that knowing can out of habits drift towards senses and change from being unloaded and unburdened into a loaded and burdened mind. Cause…engagement and establishment of vinnana’s.
I am sure you cannot trace this mind, awareness, consciousness that has lost its tendency to drift towards the senses. Impossible. I think this is refered to as anidassanam. If one would try to seek a mind without clinging, a consciousness without clinging, an awareness without clinging, a knowing without clinging, one cannot trace it, because it is like a total open emptiness that cannot be grasped and found.
I believe, in arupa jhana of endless vinnana the opposite happens because then one sees the mental-conscious base. One is at that very moment a body wittness of the base of mind-base.So, in arupa jhana vinnana is not invisible but becomes visible! and at that moment experienced as endless.
The heart-base is still something different!
Maybe this is helpful.