Suppose Steve Pinker contracts a terrible progressive brain disease that destroys his nervous system from the outside in--he starts going numb and then deaf and blind and unable to control his muscles. But then neuroscience comes to the rescue, replacing each portion of his nervous system as it disintegrates with a suitably interfaced prosthesis made of silicon and wire.
Thanks to their success on the Easy Problems of consciousness, the scientists meticulously provide artificial substitutes for all Steve's brain processes, so to all outward appearances he is saved from terrible oblivion and death. Moreover, he expresses his satisfaction with his restored feeling and sight and continues speaking and writing with humor and eloquence, delighting his friends and frustrating his critics.
But can we really be sure that he is expressing his satisfaction? His body may be just "expressing" his satisfaction. Although it appears to all observers that Steve believes he's alive and well, loves his family and is only slightly distracted by the residual pain of his many surgeries, there seems to be a possibility that the apparently animate body standing before us only "believes" it is alive, only "loves" his family and is distracted not by real pain but by "pain," the bogus kind that lacks the je ne sais quoi of genuine pain.
The trouble with this hypothesis is that it declares its own untestability at the outset. There is nothing Steve could do or say under any circumstances that would provide the slightest grounds for either dismissing or confirming the reality of his experience. There could not be an objective test that distinguished a clever robot from a really conscious person.
Now you have a choice: you can cling to the Hard Problem, or you can shake your head in wonder and dismiss it. We've learned to do this before: it still seems as if the sun goes around the earth, but we know better. It's not all that hard, actually, now that we've made so much progress on the Easy Problems. Just let go.
Dennett's most recent book is Breaking the Spell: Religion as a Natural Phenomenon