Philosopher Eric Schwitzgebel has written a paper: Borderline Consciousness, When It’s Neither Determinately True nor Determinately False That Experience Is Present that I think is interesting but perhaps somewhat over-plays the idea of “vagueness” as if something different from merely being a quantity that does in fact have a continuum of values. We don’t talk of position or temperature as “vague” even though we often use vague language like “hot” and “cold” to describe them. Similarly, I think it plausible that while the description of an entity as “conscious” may be vague there may nonetheless be a fairly well defined measure of consciousness which has values on a continuum. (And if I were looking to find such a measure I would probably start by considering the amount of information that the entity is capable of storing in a way that influences its future behaviour. )
Maybe I’ll start some pages on this.