Assume for the sake of argument that (1) qualia are real and nonphysical, (2) the physical world is closed under causation (and there’s no overdetermination), and (3) apart from qualia, the mind is physical.
Now, you have experiences with qualia. But this isn’t all. You are also aware of having qualia. You can attend to your them, think about them, recall them, and respond to them. And since (given our assumptions) the qualia themselves don’t have any causal effects on you, this suggests that you have representations of your qualia. You represent your experiences as having qualia, and these representations do the causal work. Your awareness of your qualia and your responses to them are mediated by qualia representations. (I assume these are fine-grained analogue representations of some kind. You can detect and respond to changes in your qualia that you can’t conceptualize.) The representations aren’t actually caused by the qualia, of course, any more than the other effects are. They are physical states of your brain and are caused by prior brain events, but things are somehow set up so that they track your qualia perfectly.
Now consider your zombie twin – an exact duplicate of you minus the qualia. Since it is a physical copy of you, this creature will have the same qualia representations you do, and these representations will have the same effects on it as yours do on you. Call this creature a Q-zombie.
Next consider another type of zombie. This one is a physical and phenomenal duplicate of you, except for the qualia representations. It has the same qualia you do, but no representations of them; the brain circuits involved have been fried. Call this creature an R-zombie (for Representational zombie).
The Q-zombie will take itself to have qualia just like yours, and it will display the same qualia-related sensitivities, thoughts, and responses you do. It will have the same reactions to pain and pleasure, the same sensitivity to colours, sounds, and smells, and the same beliefs about the character of its conscious experiences, even though it has no qualia at all.
The R-zombie, on the other hand, will behave – well, like a zombie. The absence of qualia representations will have drastic consequences for its mental life and behaviour. It will not attend to its qualia, or think about them, or respond to them. It will exhibit various ‘blindsighted’ behaviours, reacting unconsciously to external stimuli, but it will show no sign of having conscious experiences and no awareness of pain, pleasure, colour, smell, or any other phenomenal property — even though it does in fact have exactly the same qualia you do.
Now here’s the punchline. Something really unpleasant is going to happen to you – something that will cause a lot of pain (and pain representations). There is an anaesthetic on offer, however. In fact, there are two drugs available: blue pills and red pills. A blue pill will turn you temporarily into a Q-zombie and a red pill will turn you temporarily into an R-zombie.
Which pill would you take? And would you have any trouble deciding?
Image credit: Red Pill or Blue Pill? by Tomaž Štolfa