In the 40s, the argument was that computers will never think because they are made of matter, Turing rebutted this by saying that brains are made of matter and introduced The Turing Test, which was then replied to by Searle with his famous 'Chinese Room', which to my mind just made all consciousness suspect, even humans.
At every stage, though, computers have outpaced the predictions for their capabilities, and as you say, the unknown wall that blocks this march is yet to be seen.