In order to make the question of philosophical zombiehood more palatable, it is a good idea to first reduce the scope of the question from consciousness in general to a particular kind of awareness, such as visual awareness or sight.
consciousness (general awareness) | particular awareness (sight)
Building on this analogy, we can now say that an equivalent of a philosophical zombie (p-Zombie) as far as sight is concerned might be a person who is blind, but uses a seeing eye dog to ‘see’.
As with blindsight, there seeing eye dog provides a case where a person is informed about optical conditions in the world, but without the benefit of first person phenomenal experience of seeing. The blind person sees no visual qualia – no colors, no shapes, no brightness or contrast, yet from all appearances they may be indistinguishable from a sighted person who is walking their dog.
Staying with the analogy to consciousness in general:
(a p-Zombie) is to (a Blind person w/ guide dog)
(Conscious subject) is to (a person walking dog)
Some might object to this analogy, saying that because a p-Zombie is defined as appearing and behaving in every way like a conscious subject, and a sighted person walking their dog might not always act the same as a blind person with a guide dog. It’s true, in the dark, the sighted person would be at a disadvantage avoiding obstacles in their path, while the blind person might not be affected.
This, however, is a red herring that arises from the hasty definition of philosophical zombie as one who appears identical in every way to a conscious subject, rather than one who can appear identical in many ways. Realistically, there may not even be a way to know whether there is any such thing as a set of ways that a conscious being behaves. A conscious being can pretend to be unconscious, so right away this is a problem that may not resolvable.
Each conscious being is different at different times, so that presuming that consciousness in general has a unique signature that can be verified is begging the question. Even if two simple things seemed to be identical for some period of time, there might be a chance that their behavior will diverge eventually, either by itself, or in response to some condition that brings out a latent difference.
So let’s forget about the strong formulation of p-Zombie and look instead at the more sensible weak formulation of w-Zombie as an unconscious object which can be reliably mistaken for a conscious subject under some set of conditions, for some audience, for some period of time.
By this w-Zombie standard, the guide dog’s owner makes a good example of how one system (blind person + sighted dog) can be functionally identical to another (sighted person + sighted dog), without any phenomenal property (blind person gaining sight) emerging. As with the Chinese Room, the resulting output of the room does not reflect an internal experience, and the separate functions which produce the output do not transfer their experience to the ‘system’ as a whole.
From the guide dog analogy, we can think about bringing the functionality of the dog ‘in house’. The dog can be a robot dog, which can then be miniaturized as a brain implant. In this way a blind person could have the functionality of a guide dog’s sight without seeing anything. It would be interesting to see how the recipient of such an implant’s brain would integrate the input from it. From neuroscientific studies that have been conducted so far, which shows that in blind people’s brains, tactile stimulation such as reading Braille, shows up in the visual cortex. I would expect that the on-board seeing-eye dog would similarly show up, at least in part, in the regions of the brain normally associated with vision, so that we have a proof of concept of a w-Zombie. If we had separate digitized animals to handle each of our senses, we could theoretically create an object which behaves enough like a human subject, even within the brain, that it would qualify as a weak p-Zombie.
As a final note, we can apply this understanding to the oft misquoted philosophical saw ‘If a tree falls in a forest…’. Instead of asking whether a sound exists without anyone to hear it, we can reverse it and ask whether someone who is awakened from a dream of a tree falling in the forest which nobody else heard, was there a sound?
The answer has to be yes. The subjective experience of a sound was still experienced even though there is no other evidence of it. In the same way, we can dream of seeing sunlight without our eyes receiving photons from the sun. We can say that seeing light or hearing sound does not require a concurrent physical stimulation but we cannot say that physics requires any such qualia as seeing light or hearing sound. To the contrary, we have shown above that there is no empirical support for the idea that physical functions could or would automatically generate qualia.Thus, the case for materialism and functionalism is proved in the negative, and the fallacy of the systems reply to Searle is revealed.
And if the cloud bursts, thunder in your ear
You shout and no one seems to hear.
And if the band you’re in starts playing different tunes
I’ll see you on the dark side of the moon. – Pink Floyd