People who lack visual mental imagery have atypical performance on certain kinds of cognitive tests, as Yvain's article describes, and if I believed that such people existed, I would expect that testable difference. What type of test should I expect to distinguish between those who have qualia and those who do not?
The most direct test would be this:
"Do you have qualia?"
But you'd have to use naive subjects who haven't philosophised themselves into ignoring their own experience.
A little more indirectly, people without qualia would profess puzzlement at the very idea, and argue that there is no such thing. If they are philosophers, they will write articles on the incoherence of the concept. If they are psychologists, they will practice psychology on the basis that mental phenomena do not exist. If they are teachers, they will see the brain as a pot ...
This is our monthly thread for collecting these little gems and pearls of wisdom, rationality-related quotes you've seen recently, or had stored in your quotesfile for ages, and which might be handy to link to in one of our discussions.