Consciousness is multiply realisable
A given mental state may be realised in a multiplicity of mediums, because only the functional organisation of the system counts, not the medium in which it is instantiated.
Hilary Putnam (1967).
Note: also, see the "Is the brain a computer?" arguments on Map 1, and sidebar "Formal Systems: An Overview" on Map 7.
The Putnam argument
Putnam argues:
"Consider what the brain-state theorist has to do to make good his claims. He has to specify a physical-chemical state such that any organism (not just a mammal) is in pain if and only if (a) it possesses a brain of a suitable physical-chemical structure; and (b) its brain is in that physical-chemical state. This means that the physical-chemical state in question must be a possible state of a mammalian brain, a reptilian brain, a mollusk's brain (octopuses are molluscks, and certainly feel pain), etc. At the same time, it must not be a possible (physically possible) state of the brain of any physically possible creature that cannot feel pain. Even if such a state can be found, it must be nomologically certain that it will also be a state of the brain of any extra-terrestrial life that may be found that will be capable of feeling pain before we can even entertain the supposition that it may be pain" (H. Putnam, 1967, pp. 200-201).
References
Putnam, Hilary. 1967. Psychological Predicates. In Art, Mind, and Religion, edited by W.H. Capitan and D.D. Merrill, pp. 37-48. Reprinted as "The nature of mental states" in The Nature of Mind, edited by D. Rosenthal, 1991, pp. 197-203.