Philosophy, et cetera: Non-Physical Questions: Would you still be conscious if your neurons were replaced by (functionally identical) silicon chips? It seems like this is an open question. But how do physicalists accommodate this datum? We know (by stipulation) all the physical facts of the story: we know that the resulting "brain" is functionally/computationally no different, but that the matter it's made of is different. If the physical facts exhaust the facts, then it doesn't seem that there's anything left for us to wonder about the situation. But clearly there is something more we can wonder about. We can wonder whether silicon brains would still give rise to qualia (phenomenal consciousness), as biological brains do. We can similarly wonder whether Block's "Chinese Nation" (a functional analogue where individual humans communicating via walkie-talkies play the role of neurons) is really conscious. There's not any physical fact we're ignorant of here. So if there's a substantial fact we remain ignorant of, it must concern a matter over and above the physical facts. That is, it must be a matter of non-physical fact.
The number of neurons in the brain is the same as the population of twenty earths. Suppose it takes ten seconds for each walkie-talkie call to be made. A given human "neuron" would have to poll on average 500 others through its "dendrites"--that's an hour and a half for each brain clock cycle. Brain clock cycles are on the order of a millisecond...
This means that twenty earths of people communicating on walkie-talkies with each other full time could get one human second's worth of thinking done in 1.5 hrs x 1000 sec/ms = two months. That's six seconds a year--ten minutes of thinking a century.
I don't know whether Richard Chappell believes that Block's Chinese Nation is really conscious--I am not sure whether I believe that Block's Chinese Nation is really conscious--but it's not because I am uncertain about any matter of non-physical fact. It is because I am uncertain of the meaning and definition of "really conscious."
It can, after all, form the cogito--but it would then take it a year to spit it out.