Facebook is working on a wearable brain-computer interface (BCI) which will allow people to type words by thinking them.

At the moment, BCI is implemented by implanting electrodes in the brain. However Facebook has reached the point where it feels this can be usefully pursued using non-invasive techniques.

“We’re a long way away from being able to get the same results that we’ve seen at UCSF (University of California at San Francisco) in a non-invasive way,” says Facebook which has a team at UCSF working with rather university.

Despite being a long way from matching the results of  invasive techniques, Facebook says they have started work on pursuing exactly that with a system using near-IR light.

Currently, patients with speech loss due to paralysis are limited to spelling words out very slowly,” says UCSF Professor Edward Chang, “but in many cases, information needed to produce fluent speech is still there in their brains. We just need the technology to allow them to express it.”

Not everyone thinks it’s a good idea. “To me, the brain is the one safe place for freedom of thought, of fantasies and for dissent,” says Nita Farahany, Professor of Law and Philosophy at Duke University.