[arnoooooo]

I can't think of any test, no.

But I don't think this makes discussions about consciousness useless. If you tell me something about your consciousness I can check if it fits my experience, and you can test something I say for yourself.

What this means is that there might not be an absolute truth about this, only relative truths.

But then, this applies to anything, as no experience can happen outside of consciousness, so all of science is the same way.