Palmer's color room argument is first contrasted with a different argument by Tim Maudlin against the sufficiency thesis of strong AI. This thesis turns out to be false and hence we need to determine the relevant supervenience base of phenomenal consciousness. That could be done by causal theories and intraindividual experiments. Finally, even if we cannot explain the intrinsic character of conscious states, we may be able to know what the experience of another person is like.