Reading Kurzweil's new book The Singularity is Nearer.

New word to use: "Qualia"

These are the inner "thoughts" that you have that are evidence of your consciousness. Unfortunately, there is no way to detect them using an external sensor. We can detect the electrical pulses and oxygen and bloodflow, etc. But we cannot confirm that they create specific thoughts.

That's your consciousness.
And, nobody can prove that you have it.

So, we may never prove that AI has become conscious.