Consciousness of visual forms, sounds, smells, tastes, tactiles and mind-objects are all distinctly different from one another. So, one could directly perceive that consciousness is inconstant with regard to it's object. But that quality of 'knowing' - how can it's disappearance be directly discerned?
What arises is called Contact, it lasts for one moment and it's gone, next moment is diffrent Contact. This doesnt stop when we sleep.
Consciousness, perception, feeling and discernment are connected in sense that what is cognized is felt, what is felt is perceived, what is perceived is discerned, what one discerns one thinks about. We can differentiate between them in this way , "consciousness is what cognizes", "feeling is what feels", "discernment is what discerns" and "perception is what perceives" etc but this is it, there is no more delineating of them apart from this kind of differentiation which is really delineation or categorization of Contact. Apart from this "conceptually-functional" for lack of a better word separation, there is not diffrence, it is all merely and only Contact.
Why dont we just note contact, contact, contact instead of Satipatthanas id ask myself. I would answer that it would not be useful because we have to make sense of conceptual reality which is Samsara to remove delusion, we need to understand the nature of Five Aggregates so that we understand Contact, Diversity of Contact and it's origin.
here from the Suttas
“Friends, on account of eye and forms arise eye consciousness. The coincident meeting of the three is contact. On account of contact feelings arise; what is felt is perceived; of what is perceived there is thinking; in thoughts there is diffusedness; on account of that, diffused perceptive components of forms of the past, future, and present cognizable by the eye consciousness arise and behave in that man.
One more translation:
"Dependent on eye & forms, eye-consciousness arises. The meeting of the three is contact. With contact as a requisite condition, there is feeling. What one feels, one perceives (labels in the mind). What one perceives, one thinks about. What one thinks about, one objectifies. Based on what a person objectifies, the perceptions & categories of objectification assail him/her with regard to past, present, & future forms cognizable via the eye.
"Feeling, perception, & consciousness are conjoined, friend, not disjoined. It is not possible, having separated them one from another, to delineate the difference among them. For what one feels, that one perceives. What one perceives, that one cognizes. Therefore these qualities are conjoined, not disjoined, and it is not possible, having separated them one from another, to delineate the difference among them."
Friend, feelings, perceptions and consciousness are associated and not dissociated and it is not possible to differentiate them and show them apart: Friend, the felt is perceived, and the perceived is consciously known Therefore these things are associated and not dissociated and it is not possible to differenciate them and show them apart.
http://www.accesstoinsight.org/tipitaka ... .than.html
https://www.awake.kiev.ua/dhamma/tipita ... ta-e1.html
http://www.awake.kiev.ua/dhamma/tipitak ... ta-e1.html
http://www.accesstoinsight.org/tipitaka ... .html#fn-1
If this doesnt make sense at all then ignore it
If someone gets it then Sadhu and id like comments, because to me it is really difficult to further articulate the nature of Nama&Rupa and the function of these two in relation to the concepts in this thread and eachother.