> A lot of people find it credible that a hugely complex fast computer system could be intelligent.
But not John Searle...so it seems clear that scale has nothing to do with the thought experiment. For Searle, a vast room or an army of people to carry out instructions make no difference.
> Many of them seem to find it convincing that a man in a room with a book can’t “understand Chinese” when he personally doesn’t
The people who read the thought experiment this way don't understand it. In the thought experiment neither the computer program (no matter how powerful the computer is) nor the man and the room understand Chinese.
> But the only difference between them is scale.
No, the point of putting a man in the room is that we all agree that a human is capable of understanding. From his vantage point in the room, he can see that the program works by executing instructions without any understanding. All the room does is demystify a hypothetical computer program that can pass a turing test.
Searle is not arguing that a machine with understanding/consciousness is impossible. He's arguing against behavioralism ("if it can pass a turing test it understands"). He take the psychological phenomenon of "understanding" (something we're all familiar with) seriously, he thinks it represents a real thing, and that a computer that can pass a turing test doesn't necessarily have it.