Bernardo Kastrup just posted an addendum on his blog as a response to Sam Harris's footnote on brain as "reducing valve" hypothesis. nice. why don't you guys do a formal debate already! :)
"Harris wrote an addendum to his post, which you can find here. In it, he equates the 'filter hypothesis' to what is known as the 'transmission hypothesis,' according to which consciousness is a kind of radio signal received by the brain. He then proceeds to correctly point out the problem with the transmission hypothesis, which is that we are supposedly the signal, not the radio.
However, although the transmission hypothesis entails the filter hypothesis, the filter hypothesis does notnecessarily entail the transmission hypothesis. As a matter of fact, the filter hypothesis doesn't even entail dualism! My own metaphysical position, for instance, is not dualist. Yet, the filter hypothesis holds well under my views, as I wrote about in this earlier article, which I encourage you to read. According to this article, the brain is the partial image of a process by means of which mind localizes itself, 'filtering' everything else out. Notice how this solves Harris' question: Instead of being an external 'signal' that is no longer being received, but which we still are, in my formulation mind folds in on itself in the form of a vortex, limiting its own breadth. We are mind, and yet mind self-limits. Under this formulation, to say that electrochemical processes in the brain are the cause of consciousness is as illogical as to say that lightning is the cause of atmospheric electrical discharge; or clots the cause of coagulation; or fire the cause of combustion. Fire is the partial image of the process of combustion as viewed from the outside and, as such, correlates very well with the process it depicts; just as electrochemical processes in the brain correlate very well with conscious states.
Currently, I am 2/3 of the way through writing a new book that will explain all this in details, and very specifically. That book will be my ultimate reply to Sam Harris. So please bear with me while I finish and publish it. It should be available at some point in 2013.
It is true that even I have used the radio metaphor when discussing the filter hypothesis. After all, the analogy is a very handy, metaphorical device to convey certain ideas. For instance, I once wrote a fairly elaborate explanation of the filter hypothesis under an implicit dualist metaphor. The article is availablefrom here. But my use of the radio metaphor does not mean that I believe consciousness to be literallysome kind of external signal being received by the brain. I don't. Assuming that would amount to taking the metaphor way beyond its intended scope.
Overall, Harris' understanding of the filter hypothesis seems to be based on an extremely casual and limited reading of it. Huxley wrote two paragraphs about it in The Doors of Perception. When Bergson wrote about it in Matter and Memory, his point was to discuss memory. Before Harris can pass judgment on the hypothesis, he needs to, at the very least, acquaint himself with a proper articulation of it. For instance, he should read my paper on it, and then my idealist formulation of it."