From Cosma Shalizi's review of Daniel Dennett, Brainchildren
The standard objection to Dennett's view of the mind is that it makes no allowance for the difference between creatures with inner lives, namely us, and those without, namely zombies. Zombies might have quite sophisticated dispositions and sensitivities to their external environment, and even to their own information-processing (so the objection goes), but they'd have no inner experience --- they might be able to discriminate red roses from yellow roses, but they'd have no experience of redness, no red qualia. Dennett's quite characteristic response to this objection is to argue that there is no defensible difference between sufficiently nuanced sensitivities and qualia. Consider the case, he asks us, not of zombies per se but of zimboes, who are behaviorally just like us conscious human beings, but have no inner lives. Zombies are the mindless malevolent minions in a Boris Karloff movie; zimboes, when villainous, are more in the Sidney Greenstreet line but, by hypothesis, they show just the same range of heroism, vice, and moral muddle that we do. They'd certainly talk and act as though they thought they had qualia. Maybe brain damage can make people into zimboes --- only they'd insist nothing was wrong! Maybe lots of people (all, of course, normal-seeming) are zimboes --- John Searle, for instance, or this reviewer, or your landlord. They could be everywhere. Consciousness could be a genetic abnormality. Even your best-beloved could be a mere zimbo. In fact, how do you know that you are not a zimbo?
Dennett's answer is that you don't, because, as it happens, you are. Turned around: zimboes, creatures with sophisticated sensitivities to the external world and their inner environment, enjoy just as much consciousness as there is to be had.