Hello, everyone 
Of course! The question is just a matter of what the conditions for consciousness are. My point is that consciousness seems not to be only dependent on the individual sense organs and sensory stimuli. This is obvious enough, as even though light comes into range of an eyeball, the person must be alive for consciousness to register. It’s just a matter of drawing out and connecting the different implications.
I would say that consciousness in early Buddhism is described in two overlapping ways. One is a description of the domains of consciousness, i.e. the six sensory domains. The other is a description of the karmic stream of consciousness conditioned by volition and nāmarūpa. We could say that the first answers “where and how” and the second says “why and who”. Both combined tell us “what” viññāna is.
I think that it is potentially the over-emphasis on the first description that lead some historical Buddhists to posit more detailed theories about the latter.
The example with the fire smouldering is good. In that case, there is still some heat remaining, as well as a basis for the heat (i.e. the wood fuel and oxygen). In this case, the wood is like the sense organ, as the fire arises in dependence on the wood pile. The oxygen is like the sensory stimuli, as it comes in the vicinity of the sense organ to stimulate the fire. The fire is like consciousnesses, which burns in dependence on the two and gives off light.
But imagine that there were no heat remaining or smouldering. The fire has completely gone out. We could analogize this to the cessation of perception and feeling. And then, all of a sudden, the fire re-emerges from cold wood and no particular contact w/ oxygen to cause combustion. This would stand for the re-arising from a cessation attainment.
In this case, we would need to update our understanding of the conditions for fire to arise and persist. Note that it still arises w/ the wood pile and in an oxygenated environment, so the fire — so long as it is burning — still depends on the internal and external conditions, never otherwise. But there is some other component here, a third condition, that is necessary.
I believe this is why ‘saññāvedayitanirodha’ is not called ‘the cessation of consciousness.’ ‘Saññā’ and ‘vedanā’ are said to be inseparable and fundamental to the structure of ‘viññāna.’ So if one of these disappears, the others by extension also would not be present. However, ‘viññāna’ here would imply the whole stream or aggregate of consciousness, or the principle of samsāric existence. It parallels ‘bhava’ in dependent arising. So the cessation of viññāna really only seems to be used to refer to nibbāna, as any other temporary cessation does not imply viññāna coming to a real end.
The Pāli texts explain this attainment as saying that the faculty of life (jīva) is not gone. In some parallels available in Chinese, it also says that consciousness has not left the body, or something along those lines. I’d say both of these would be referring to ‘viññāna’ as the principle of continued existence conditioned by volition/kamma and dependent on a particular psycho-somatic structure (nāmarūpa). The individuation of this stream is the ‘who,’ i.e. the karmic conditions and the particular psycho-somatic organism it is dependent on (and it turns out this ‘who’ is a conditioned temporary process, hence anattā). The grasping and ignorance-influenced volitions also tell us why it continues to arise at the sense organs, compared to a dead body, and across lives when some prior sense organs may cease.
It’s important to note that both of these two overlapping dimensions of ‘viññāna’ have to be borne in mind. If we understand only in terms of the ‘where’ of the six domains, several problems arise. But if we understand only in terms of a stream that continues, it’s possible to conceive of consciousness as some kind of solid/permanent transmigrating entity, as at MN 38, where the Buddha goes on to describe how the actual experience of consciousness is still of a conditioned plurality, despite there being a degree of continuity in terms of kamma & rebirth. Just like the fire re-arising at the wood pile with oxygen, and there not being any kind of higher secret fire invisible there.
What I said above should clarify and respond to some of what you’ve said. Conscious experience is completely intertwined with vedanā and saññā, yes. But what I was pointing to in my main post and above is that the term ‘viññāna’ is also used in a broader sense than mere individual instances of awareness in sensory domains, while also not going beyond those sensory domains to posit some kind of “higher” consciousness. With the concept of ‘ālaya-viññāna’ here then— it is not that it is designating a form or domain of conscious experience, but that it is describing the karmic stream of consciousness which is made up of those same sensory consciousnesses.
An example would be of a literal stream, or river. Let’s imagine it is only made of ‘water,’ excluding dirt and so forth. We could say that the stream is made of individual drops of water, but by “stream” we do not mean individual drops of water nor is a bunch of drops of water sufficient to quality as a “stream.” There has to be some momentum, flow, or movement going on whereby the water that makes up the stream is carried forward.
In the same way, viññāna is comprises of awareness in the six domains, but it also entails more than just those parts. There is another condition, this being the karmic momentum and stationing of it within particular births and sustained by upādāna. We might ask: what is the difference between someone being knocked completely unconscious in all six domains, then waking up, and someone understanding the cessation of the six sense domains / consciousness? I would say that it is the difference between mere parts and a meaningful whole: one has to give up the stream or continuation of consciousness itself, which entails some relinquishment of ‘upādāna.’ Without this condition, even if all consciousness(es) cease, there is still that third condition (sankhara/upādāna) which allows it to re-arise, like with the fire analogy above.
Likewise, based on previous stationing / kamma, this conscious stream is tied to a current nāmarūpa (or alternatively described as the four stations of consciousness—the four other aggregates). So long as these persist, consciousness is karmically bound to them—not any particular domain of consciousness, but the general stream of consciousness.
This is not my own idiosyncratic usage of terms. As I mentioned before, we have reference in the suttas to ‘asaññāsattā,’ or beings who are reborn with no saññā. That is, this is a ‘domain of consciousness,’ explained in tradition as comprising only the station of form (rūpa). Obviously, there must be some continuity of the stream of consciousness, otherwise this would completely disrupt the flow of kamma and so forth as understood in early Buddhism. But there is no sensory consciousness arising at that time.
I can’t answer this to accurate satisfaction. But as I referenced in the post, I think there are/were different understandings of “ālaya-vijñāna” within and without the Yogācāra tradition. I am not trying to confirm any of those positions, but am taking the concept and ideas behind the discussion of ‘ālaya-vijñāna’ as a spring board to look more deeply at those questions from the perspective of the early discourses.
—
Thank you everyone for your contributions. I hope this has helped shine light on the implications a particular model of consciousness has for the ideas of early Buddhism—from kamma and continuity all the way to liberating wisdom and liberation. Ultimately, we want something practical and descriptive, both of which I believe are accurate terms for the model that seems to be presented in the EBTs. It says just enough.
EDIT: Another reference to this usage of ‘viññāna’ is in the list of abhiññās (higher knowledges), where one is said to be seeing how consciousness is tied up with the physical body, with the simile of a beryl gem attached to a string. Here ‘viññāna’ is not any particular instance of sensory awareness, but stands for the larger aggregate and stationing of consciousness w/ nāmarūpa.