I see the Skandas as a description of how physical reality is experienced by awareness and then there is a separate subconscience selfing process that is entangled with them.
Okay, so here I can say that at the form level, "rupa", there is no awareness that knows that place
(but form exists and has a very basic formness, and this is not nothing... so its existence and the ability to experience the existence of form is part of the human brain...so at that very basic level one could say there is awareness in form; but there's absolutely no consciousness or volution or sensation in that skandha: it's as close to gradientless machine-"knowledge" that I think I can have experienced)
What happens is that the brain experiencing form (up from a hindsight of nothingness (no form, no anything) only
knows "form" when a layer of "familiarity" then comes on (recognition skhanda in the Theravadan buddhist model) and it is in that transition to familiary that there is hindsight experience of non-familiarity, no gradients within form, just form. Not even form knowing form.
In the form khanda there is just form, no awareness can root down to this skhanda or that experience will be an experience of volition (i.e., the want to know form, the self-direction to look for form, the mind retaining thoughts regarding skhanda-hunting/feelings to study skhanda, etc), consciousness (a brightness/attachment/spark within awareness/the "ego ingredient" in the skandas -- a skanda that relates to craving), feeling (any feeling whatsoever: wanting to know rupa, mere directing oneself to know rupa).
In short, there is no way for a person to directly go to the form skanda without being in the tangle of all aggregates functioning at once with particalur obfuscation occurring from the consciousness skhanda-- that one that adds a kind of specialness/ brightness/ connection/ego ingredient.
So to let the mind go very, very, very well into a gentle concentration practice is to let the mind -- particularly the volitional and consciousness skhandas-- drop themselves away. Then, among many other experiences, the brain may show a full shut down and re-ignition through the skhandas.
Rupa is, in hindsight, a totally un-anticipatible experience lacking any aspect of awareness mind, but form itself: there is just form and it is when the skanda of recognition--- something very akin to actual naming, but not naming, just the sensation of familiarity. And that skhanda of familiarity/recognition has an nearly identical feeling as when one says a name of an object, like "mountain".
This is something I came up with as I investigated how things have turned out for me and looking into 3rd path work and seeing differences in advice and from previews of experiences.
What I would say to anyone considering such a mapped correlation of skhandas and "paths" is that in my direct experience of mind shutting down and then re-igniting individual skhandas until "sense of self/me" re-emerges and inherently responds to that whole experience of shutting down/re-ignition (if only by having a memory and a "wow? what was that?") there is no specific path correlation, simply by way of my one example. That full cessation/re-ignition was stream-entry, each skhanda clearly experienced up from nothingness, not a fourth path passage.
That full shut-down and re-ignition is very, very useful on a number of fronts but I can say for myself and speculate for others that no one wants to live from the rupa skhanda --- what makes the human feel good and connected and engaged (but also clingy/clinging) is that consciousness layer, the brightness of the skhanda of consciousness***
. It is immensely gratifying when that one re-ignites. I remember the feeling of lurching at it, like a fish grabs food from the water surface -- that skhanda is the part that is warned about in the sutta regarding the Magic Show.
But, like, craving, if one is aware of what the senses are with and without craving, there's not need to deny pleasurable sensations so long as one is not under that control (umm, that's hard). And the same goes with seeing that consciousness skhanda-- it is the brightness of one's own sentience, but it is not inherent or permanent. It rides on the other skandas. Anyone who's experienced paralysis and lack of breath/sense of dying in meditation -- even without a full mind shutting down and full re-igntition of the skandhas knows that the consciousness skhanda-- none of them are permanent. In some ways the self, me, becomes very special, just the knowledge that it and others around it are impermanent and it's nice to respect and enjoy its life, create conditions for its well-being, which in our species often will support the well-being of others.
So anyway, a person drops all this directed aiming for skhanda knowledge and does focusing meditation practice (concentration) and the brain shows on its own all kinds of experiences, including dropping all the skhandas, fully ceasing and then re-igniting the mental layers/components/ the skandhas. That's my experience anyway. Meditation is fun sometimes : ]
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*** People have mentioned a consciousness outside of the skhanda of consiousness; about this I don/t know. What I can say for myself is that in the arupa jhana it is very clear to me even as a relatively newbie practitioner that it is the basic skhanda of consciousness that is a part of arupa jhana -- not some other consciousness, except perhaps the sense of meeting/joining other consciousnesses -- but that in arupa jhana other skhandas can be very subdued, such as volition being apparently absent sometimes.