We can all agree on what color something is, but we can’t describe the color a priori, only by example. I think consciousness may be a similar phenomenon and the only test is by shared experience. If so then we are in deep trouble because we will not be able to anticipate when a system becomes conscious.
Why cannot this be applied to consciousness as well? I mean, it's surely much more difficult to do compared to colors but... impossible?
Previous comment used the word "anticipate" and I think they mean that we won't know in advance before we run the trial and error process.
When they say "deep trouble" I assume they mean because creating a non-friendly conscious AI might pose an existential risk for humanity.
However there is also the ethical issue of creating a consciousness and then destroying/murdering it.