Some people pin their hopes on future science for a solution of the problem of consciousness as if hope, which has a place in religion, has any place in a strictly scientific worldview. If we only knew enough about the brain, these people opine, we would understand how consciousness arises from it.
But consider an analogy. Suppose you explain to a person that the natural number series is infinite, that there is no largest natural number since for every n, there is n + 1. The person seems to understand, but then objects when you say that it is impossible that there be a largest natural number due to the very nature of the natural number series. Your use of 'impossible' sticks in the guy's craw. He tilts Leftward, you see, and he thinks, quite confusedly, that anything's possible. He doesn't like it when people invoke natures and impossibilities and necessities and lay claim to a priori knowledge. That's too rigid and static for his taste. So he says,
Before long, we will have supercomputers so fast that they can reach the end of the natural number series. Who are you to say that that it impossible? All sorts of things have been pronounced impossible that are now actual. Given the enormous strides being made in computer technology, it is just a matter of time before a computer will reach the end of the natural number series.
Now the rank absurdity of this is (I hope!) self-evident. The fastest possible computer will operate at a finite speed: the speed of light (186, 282 mi/sec) is a speed faster than which no signal can travel. Combine your nanotechnology with cryotechnology, get down near absolute zero, there is still an upper bound on computing speed.
Now here is the analogy. Just as no computer no matter how fast will ever reach the end of the natural number series, no amount of brain science will ever find consciousness in the brain, or explain how consciousness arises from the brain, or how it could arise from the brain.
No doubt some of you will protest that the two situations are disanalogous. But then the burden is on you to explain exactly why they are.