The best theory of consciousness must be able to encompass all others, be they physicalists, philosophical, even mystics. Why is there such a diversity of responses? They are born in a dimension called complexity. Yet it is precisely in this complex dimension that consciousness is patiently built.
The scale of complexity varies considerably from the micromechanisms of matter to a human equipped with a brain, to micro-organisms, plants and less evolved animals. A large number of levels of information are added. The brain is a set of molecules, but also cells, nerve centers, and finally conscious integration.
All of these levels of information occupy the same space. How are they intrigued? How do they have relative independence? A set of biomolecules is not necessarily a living being. Why is such a set called 'cell' and another set, in a drop of water, is only a 'molecular soup'?
The question is not outlandish. If we place ourselves in the middle of these molecules (look say ontological), we see only sets of relationships. There is nothing at this level to suggest that one of them is a cell. For the 'cell' to present itself as such, you need an observer, something that looks at it (so-called epistemic gaze). It takes something that interacts with it because of its particular properties.
Representing a level of information therefore implies reaching that level or higher in the scale of complexity. The tricky question is: Is the cell already a representation of itself? It is possible to answer yes with strictly physicalistic arguments. The level of information 'cell' is indeed a self-representation of its constitution.
Indeed, the constitution of the cell is a permanent dynamic, a "balance on the brink of chaos". It must constantly find sources of energy to spend. Despite these continual changes it remains the same 'cell' in the level of information where it interacts with other microorganisms. As a cell it makes exist a merged representation of its successive states. A real layer of additional information.
The most important thing to understand is this: How do we go from 'representation' to 'consciousness'? The 'cell' as an additional level of information is not isolated from its constitution. This is a relative independence. Any serious disruption to its constitution makes it disappear. The 'cell-representation' is only the higher level of information; but the 'cell-entity' is the over-imposition of all levels of constitutive information, from quantum interactions. That is what defines it as a substance.
Our brain is an extraordinary organ for codifying data. It is capable of simulating any level of information. Our mind is a set of representations of the body and the environment. This ability allows our mind to represent the previous cell. But not to experience herself like her. Here is the difference between representation and consciousness. The brain can simulate each of the cell's information levels but not intricate them to "feel it".
But the human brain is not to complain. Its groups of neurons build up a very large number of levels of information as it matures. See graph theory and depth of information. The consciousness experienced by our brain is thus of a depth much greater than that of the cell, by the addition of the very large number of representations superimposed by neural groups.
This proven consciousness is specific to each individual. It is not reducible to all conscious representations, i.e. to the breadth of knowledge. This set is only the upper layer of mental integration. Underneath we perceive 'little voices', body impressions and emotions… that make all the richness of this conscious experience.