In general, you can;'t generalise about the testability of things like consciousness and free will, when there are a lot of different theories and definitions of both.

I agree: in fact, you usually can't generalize about any property of thing X for different, contradictory or unrelated, definitions of "X". Here, like in the subthread about consciousness, I wasn't trying to generalize.

I was using the definition used in the comment I was replying to, which - implicitly but clearly - talks about a deterministic universe and a supernatural free will. I should have made that explicit.