Mental states only arise under the constraints of natural law
To generate mental states, information flow must be guided by natural laws—in the China example, it's guided by human activities. So the people of China don't give rise to a mental state, nor should a functionalist expect them to.
Note: Pollock is not arguing against functionalism, but is adding a requirement that any functionalist theory must satisfy.
John Pollack (1989).
The Pollock argument
John Pollock argues as follows:
"The reason we resist attributing mental states to the nation of China (or to a structure consisting of its citizenry) in this example is that insofar as the citizens work together to mimic the behavior of my mental states, they do so willingly. There may be a certain amount of government coercion, but they resist thinking of their joint behavior as dictated by rigid laws of nature. On the other hand, for there to be a rationally adequate mapping from states of the nation of China to mental states, it is required that the citizenry form a structure whose behavior is dictated by ordinary physical laws to mimic rational architecture."
He concludes:
"Thus, insofar as the behavior of the Chinese citizenry is not dictated by laws of nature, it does not follow from (R-BASE) that a structure composed of them has mental states. On the other hand, if we decide that we really can build a physical structure out of human beings in such a way that laws of nature dictate that it will mimic rational architecture, then it is not obvious that it cannot possess mental states. In the latter case, that the structure is made out of human beings seems incidental to whether it can possess mental states" (J. Pollock, 1989, p. 78-79).
This quote appears as it was cited by Bringsjord, 1992, p. 221-222.
References
Bringsjord, Selmer. 1992. What Robots Can and Can't Be. Boston: Kluwer.
Pollock, John. 1989. How To Build a Person: a Prolegomena. Cambridge, MA: Bradford Books, MIT Press.