Jackson’s Mary’s room setup
Never understood why it is considered good—isn’t just confusion between “being in a state” and “knowing about a state”? The same way there is a difference between knowing everything about axes and there being axe in your head.
The hard problem is more like “what part of the Schrödinger equation says that it describes non-zombie world”—you can point out the part, where human body doesn’t act like an agent (with interesting goals) if it is placed in the vacuum, and in principle why it does, when it does, but there are more issues with doing this with what people think of as consciousness. Personally I think panpsychism gives satisfying enough answer (“the part, where we say that the world it describes is real”), and so there is not much disagreement between hard problem and ethically-significant consciousness being non-fundamental. But it doesn’t mean the hard problem is meaningless.