In those of us lucky enough to have intact speech, the boundary between thinking and speaking is almost imperceptible. So when scientists talk about designing technology to decode the brain activity underlying speech, it is easy to think they are talking about reading people’s minds, with all the serious ethical concerns that would imply.
In reality, there is a huge gap, both scientific and technological, that makes any sinister attempt to intrude on a person’s inner thoughts virtually impossible, while decoding what they are trying to say out loud – a clinically urgent need for people with paralysis – is merely very hard.