No, it is not consciousness as per the western scientific definition. Call it proto-consciousness, if you like.
OK, I'm happy to go with "proto-consciousness".
It is not conscious as per the scientific definition, as in it is not aware or have thoughts by itself. But it is the very capacity for experience. It is the substratum that allows consciousness (again scientific definition) to exist, i.e. conscious awareness that we have. Consciousness is emergent, if you use the scientific definition of it. It can only arise through brain processes that process and integrate information, which then allows for conscious experience to occur. The capacity for experience is not emergent.
I'm suspicious of all this, basically because your notion of proto-consciousness seems slippery. In a sense (and please forgive me if this seems unfair), what you seem to be saying is, "It's not consciousness but it is; consciousness is not emergent but it is".
What does it mean to have a capacity for experience without actually experiencing? What does it mean to be a "substratum" that allows consciousness to exist whilst not being conscious?
It seems to me that there is a logical problem here: that consciousness cannot in principle arise from that which is non-conscious - especially given that consciousness versus non-consciousness is a binary distinction, not a gradation[*] - and that your approach does not (cannot) avoid this problem even though on the surface it appears to. Expanding on this: it's one thing to talk about a "potential" for consciousness experience [in that which is not actually conscious], but what does this really mean, and how is this different from being - straight-out, unequivocally - non-conscious?
[*] By which I mean that there is a sharp distinction between what we would label as "conscious" and what we would label "non-conscious", even if within the realm of consciousness there are varying degrees of (strength of) consciousness.
The questions have to stop somewhere. The question does not even make sense. It is a singularity of proto-consciousness that does not exist within spacetime. The question of why implies causation, but when you are beyond spacetime it makes no sense to ask a question of causation. To ask "how" it exists is inapplicable. To borrow a line from David Albert, it's like asking the marital status of the number four. You can ask the question, but that doesn't mean it makes sense to ask the question.
I disagree that questions of why imply causation. The answer to the question, "Why is it possible to solve quadratic equations through a formula?" is
not causal. It is logical. And I don't think we can or should assume that "causal" and "logical" exhaust the possible categories of answers to questions of "why", nor that we can or should assume that the superficially mutually exclusive problem domains to which these categories of answers seem to apply really are - ultimately - mutually exclusive. And if there is potentially an answer to "why", then there is potentially an answer to "how".
I'm not sure I understand the question, though.
That doesn't matter, because in any case you answered it later:
["Unlimited" consciousness is a]n undifferentiated state of proto-consciousness beyond spacetime.
This only confirms my initial reluctance to accept your use of these words ("limited" and "unlimited"). It seems that what you really mean by "unlimited" is "undifferentiated", and these, in my opinion, are neither readily nor helpfully synonymous. A quick check of dictionary.com confirms that neither is defined in terms of the other (and likewise for "limited" and "differentiated"), and a quick check of thesaurus.com confirms that neither "limited" nor "unlimited" are listed, respectively, as synonyms of/for "differentiated" nor "undifferentiated", and vice versa.
This of itself is not an argument against your concepts, only against the words you are using to describe them.
How can that allow for any perception, knowledge, or experience?
Your question assumes that "proto-consciousness" is a meaningful concept in the first place. As I said, I'm skeptical of this - but I'm not closed to it: I'd simply need to see it fleshed out a little more before being willing to accept that it is meaningful.
I don't think that awareness is at the base. Awareness arises through our brain. It is the process of integrating information that allows this awareness to occur. A state of pure awareness can result from an almost complete quieting of neuronal activity. Proto-consciousness underlies all this and allows for any of it to occur or be experienced.
All of this, for me, makes it questionable that you are, in fact, an idealist; it seems more likely that (on my terms/understanding) you are an emergentist, and, as I explained above, I think that there are logical problems with emergentism. But I'm open to changing my view given a more fleshed-out understanding of what you mean by proto-consciousness.
How is that a possible world? The components necessary to make the photodiode and the processes required for its operation preclude the premise that there is only one thing to experience or know.
If you check back the thread of this small part of the back-and-forth in our conversation, you will find that it was based on the notion of "pure consciousness",
not the hypothetical scenario of the photodiode, which you have just now introduced. So, my response is complicated by your own response being in a sense a diversion.
But here's a specific response anyway: the answer to your question is that it is a possible world because not all possible worlds involve photodiodes! One possible world which might qualify is that in which all that exists is consciousness which is (solely) conscious of its own existence and of its (recursively, self-)consciousness, and in which nothing else - neither change, time, matter, thoughts, "other" nor laws - exist / existed / will exist. In this possible world, the only thing to be aware of is one's own (timeless) existence and (self-)awareness: there is nothing against which to differentiate this.
The capacity is always there. It's the type and degree of information processing and integration that determines the potential for conscious experience.
This strikes me as based more in assumption than in reason(ing). But anyhow, as I said, I'd like to explore your idea of IIT more (assuming you're open to it), even though this thread probably isn't the place to do it.