Well, if the dragon exists it must have the characteristics of a dragon. Let's say it must be an animal with four legs and a tail. Currently it's unknown whether all animals are q-conscious[1]. Let's say it is discovered that all animals are q-conscious. Therefore the invisible dragon is q-conscious.
Currently we don't really understand qualia, but one mainstream theory is that qualia are a different kind of thing to anything else we know about (i.e. are non-physical).
Let's say this theory is true, and, further, that a method for detecting this different kind of thing is detected. That the dragon is invisible, floats, is heatless, is incorporeal, doesn't matter.
The theory that there is a dragon in the garage is falsifiable by the observation that a scan for qualia results negative.
You could say "ah, but this dragon is the dragon of any-test-you-can-come-up-with-doesn't-work, therefore you can't come up with any test which would work". But that would be begging the question.
Currently we don't really understand qualia, but one mainstream theory is that qualia are a different kind of thing to anything else we know about (i.e. are non-physical).
Let's say this theory is true, and, further, that a method for detecting this different kind of thing is detected. That the dragon is invisible, floats, is heatless, is incorporeal, doesn't matter.
The theory that there is a dragon in the garage is falsifiable by the observation that a scan for qualia results negative.
You could say "ah, but this dragon is the dragon of any-test-you-can-come-up-with-doesn't-work, therefore you can't come up with any test which would work". But that would be begging the question.
[1]That is, all animals have qualia.