Formal programs realizable in multiple media
The same formal program could be realized in a digital computer in a human brain, in beer cans, and toilet paper or any number of physical implementations. The program is defined soley in terms fo its formal syntactic structure.
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It's mode of physical implementation is irrelevant.
Note: For more multiple realizability arguments, see the "Can functional states generate consciousness?" argumentation on Map 6, and sidebox "Formal Systems: an Overview" on Map 7.