I have a couple of technical definitions that I can offer here, and will as time allows, but the primary purpose of this entry is to demonstrate that 'consciousness' is not a magic word defying comprehension and definition as many philosophers would like to suggest, but is in fact quite comprehensively and adequately bounded and characterized by rather prosaic if sometimes technical language. By such, then its means and capabilities can indeed by operationally functionalized and instantiated.
A Provisional Outer Limit
I point out in Defanging_Nagel's_Bat that despite the pretensions of some philosophers there is nothing particularly auspicious or magical about the notion of "what it's likeness". There is really nothing in the phrase not comprehensively addressed as a memorial comparison. However it remains the philosopher-mystic's touchstone as to the specialness of consciousness.
We can then, use that is part of a boundary post for conscientiousness. It may take more, but we can reasonably assert, and I as hardcore absolute materialist, have no objections to the following notion: If there is consciousness, there is "what it's likeness".
But as with most jigsaw puzzles, having one corner, we can then quickly piece the other corner pieces to describe the edge of our conundrum.
There is "what it's likeness", but of what? Of experiences, of course, and like unto what? We must be able to get to something our experiences are like unto, and we must have some knowledge that we know of that likeness. This gives our outer boundary:
Consciousness is SUBSUMED WITHIN the awareness and access what it's likeness of the subject's experiences
Note that I haven't said anything about how such happen nor what other consequences may be. Only that there is no merit or meaning to the notion of consciousness that is not coherent with and otherwise inside of what it talks about. It recognizes completely pure internal cognition and reflection as "experiences" in the sense that one may consider oneself fully "conscious" but deeply lost in thought internally for protracted time. One is still aware of the "what it's likenesses" of her cognitions with the outside world about which or from which such cognitions ultimately derive.