Like Lewis Carroll’s Red Queen, Elon Musk is fond of impossible things. And not content with simply believing them, Musk likes actually to get them done. He already has a formidable set of accomplishments to his name. He’s invented an electric car and put it in orbit around the sun. He’s bored impressively large holes under Los Angeles.

Now, it seems, he’s looking for a new challenge – something really hard this time. Cold fusion? Establishing a colony on a gas giant? A perpetual motion machine perhaps?

No, those things are for lesser minds. 

Having acquired Twitter for a paltry $44 billion, Elon Musk wants to turn it into a platform for untrammelled free speech.

Now don’t get me wrong, I love free speech. In fact I think it’s the fundamental value underpinning open society. Without it, there would be no democracy worth having. There would be no science as we understand it. Without free speech we would be poorer, stupider and, well, less free.

I’m close to being a free speech absolutist. But as even I will admit, free speech has some necessary limits. Credible threats and incitement to violence are out. So is libel and exposing children to obscenity.

In the real world we have laws to enforce those limits. But I don’t think that’s why, most of the time at least, we restrain ourselves from overstepping them. The real reason is that we have informal rules of politeness to keep us in line.

For the most part, those rules keep us well short of legal limitations on what we can say. If we step outside the bounds of politeness too often, we’re likely to find ourselves shunned. Human beings, as social animals, really don’t like being shunned.

But Twitter isn’t the real world, and the normal rules of social interaction don’t apply. For one thing, the 220-character restriction on each post tends to limit nuance of expression. So does the immediate nature of the discourse – it’s all too easy to tweet first and think later.

Perhaps most importantly, the consequences of rudeness are far less serious on Twitter than they are in real life. In fact people who say inflammatory things on Twitter actually seem to be rewarded. Research has shown that posts are most likely to be retweeted if they trigger strong emotions, especially rage at opposing groups.

I wish Elon all the best with his new mission impossible, but turning Twitter into a wild west for speech may not go exactly as planned.