Elon Musk promised Neuralink would bring superhuman abilities and minds merged with AI. Then he fueled a runaway hype train for his brain implant technology, which ended up with a grisly record for implants in monkeys and some success with human subjects. But for all of the hype, he’s still further away than Mars from his goal. And that’s because his relentless ambition is once again hitting the wall of scientific reality. The heart of the issue is how brain-computer interfaces (BCIs) translate