WHEN MIND AND MACHINE COLLIDE

First, Elon Musk wanted to make electric cars ubiquitous, then he wanted to make space exploration a private enterprise. Now, with Neuralink, his newest venture, Musk hopes to merge humans and artificial intelligence. Turns out, it might not be such a crazy idea...

- PETER BENTLEY

Mind-reading machines have been around for a long time. In 1895, scientist Julius Emmner believed his machine could record patterns of thoughts in the same way that sound could be recorded. Emmner took inspiration from the phonautograph, which plucked sound waves out of the air and committed their waveforms to paper.

It seemed plausible to Emmner and the world at large that he might be able to do the same with thought. His machine was supposed to record thoughts as "mental photographs", which could be replayed to someone who would receive them "in an unconscious manner".

According to Emmner, mindreading was solved: all thoughts could be recorded and nothing could be hidden. "The murderer will be confronted with proof of his crime and the punishment will be an easy task."

The state of the art

Despite the publicity it generated, Emmner's machine was soon forgotten because it didn't work-reading minds is not as simple as recording sound. Our brains have around 100 billion neurons and countless other cells that help us to remember, feel and think. We're still unlocking the mysteries of exactly how and where our thoughts are held and, to make matters trickier, we don't have access to the state of the cells in our heads, so we don't know what they're doing at any given time.

What we do know is that our brains affect our bodies and the closest thing we have to a mind-reading machine, the polygraph (more commonly and inaccurately known as a 'lie detector'), measures factors such as respiration, perspiration, skin conductivity, blood pressure and heart rate. The theory behind it is that, when we lie, we become anxious and our bodies undergo measurable involuntary physiological changes. But even the polygraph is unreliable and often inadmissible as evidence.