Hi Amit, 

If I was trying to show that functionalism was inconsistent or indeterminate then yes I would have to show that it was inconsistent or indeterminate, but that is not what I was trying to show. Dennett's position is that it has not been shown that if you know how it behaves then you must also know what-it-is-like is incorrect. So I only need to show that there is a difference between knowing how something would behave and knowing what-it-is-like to be it. 

The argument just highlights that people can agree on how it will behave but disagree about what it would be like. Some could think it would be switching between red and blue, some could think that it would be red, some blue, and a theist would probably not think it would be consciously experiencing at all.  Job done. For there to be no distinction it would mean that knowing how it behaves means knowing what it would be like. But if they can all know how it will behave and yet have different incompatible opinions about what-it-is-like then at least some of them knew how it would behave but did not know what-it-is-like, they could not even guess it correctly, and guessing is different from knowing, but I do not need to make that distinction in order to make the argument.
 
If you could tell which was right then you could know, but that does not alter the fact that there is a distinction between knowing how something would behave and knowing what-it-is-like as knowing how something would behave does not require the ability to be able to tell which theory was correct regarding what-it-is-like.

As it happens I believe the argument does also indicate that the sub-personal functionalism (as you refer to it) is indeterminate because, as I pointed out in the last post to you and James, the processing of the A, B, and C channels does not need to vary dependent upon whether which of those channel represented red, green, or blue in order to have a robot distinguishing between those colours. Did you understand my previous post to you and James? If so then I am interested in how were you thinking there would be no indeterminacy. Were you disagreeing with what I wrote, or were you thinking that even with that being the case you still had a method of determining it? 

Yours sincerely,

Glenn