Consciousness bears cognitive information similar to the way DNA bears genetic information.
Thorough understanding of biological information bearing media can only be gained by examining both the information carried by any given medium (e.g. the information carried by DNA) and the medium that carries information (e.g. the DNA itself).
But if consciousness is an information bearing medium, and if information bearing media are not multiply instantiable—although the information carried is—then consciousness is not multiply instantiatiable.
Functionalism is then false, because it claims that consciousness is multiply instantiable.
Bruce Mangan (1993).
The Mangan argument
Bruce Mangan presents his idea this way:
"I propose to formalize the notion of consciousness in a slightly new way: consciousness is simply one information bearing medium, among many others, at work in our organism. In general, scientific analysis of a biological information bearing medium (e.g., of DNA or the fluid in the cochlea) aim to answer at least two related but different questions: (1) what information does the medium bear? and (2) in what specific *way* does the medium bear its information? The 'information' asked for in the first question can be instantiated in a great many other media, natural or man made. But for the second question this freedom of instantiation is largely beside the point, for the second question asks about the *particular* characteristics of of a given medium that allow it to bears its information in a *particular* way. Answering the first question lets us assert that something belongs to the *genus* information bearing medium, answering the second lets us assert its uniqueness as a subordinate *species*. Common sense notions about consciousness usually emphasize its unique aspect, while cognitive science usually does the opposite, treating consciousness as if its generic aspect as an information bearing medium is all that we need to consider. But each stance tacitly recognizes the other in many cases, and I believe that there is no necessary conflict between them. My own candidates for answering consciousness' genus and species questions are: (1) consciousness tends to bear information that is relevant to novel evaluations either expected or at hand; (2) consciousness bears its information as experience (or 'qualia', but I try to avoid this term). Note that the general species/genus proposal is independent of this particular way of fleshing it out. The great complication here is functionalism. The functionalist intuition about consciousness (e.g., Dennett's) simply cannot allow consciousness to be interpreted as a distinct information bearing medium. For if consciousness is a distinct medium, the notion of a 'conscious content' is medium dependent. Other media could still bear precisely the same information consciousness bears. , but this, by itself, would neither make such media, nor any information born by them, conscious. One thing is clear: *If* consciousness is a distinct information bearing medium, functionalism is wrong. So the medium interpretation at least sharpens the dispute between functionalism and its enemies. Another consequence may be to show a way out of one research dead end around the notion of 'qualia,' now used as if no other more fundamental intuition about conscious experience is possible" (B. Mangan, 1996, p. 32).
References
Mangan, Bruce. 1996. Consciousness as a information bearing medium. From
Journal of Consciousness Studies series, Consciousness Research Abstracts. The Tucson II conference: Toward a Science of Consciousness 1996, p. 32.
For full paper is published as: Mangan, Bruce. 1998. Against functionalism: consciousness as an information bearing medium. In
Toward a Science of Consciousness II The Second Tucson Discussions and Debates, edited by S. R. Hameroff, A. W. Kaszniak, and A. C. Scott, p. 135-141.