History does not look fondly on the hubris of those who, like Galileo’s inquisitors, appoint themselves as arbiters of permissible speech and thought. Their authority is only ever contingent on the wisdom of their time. Today’s free speech sceptics are characterised by a similar tendency to mistake self-satisfaction for infallibility. If nothing else, the story of Galileo is a potent reminder of the importance of freedom of speech, and how none of us can ever be sure which heresies of today will become the certainties of tomorrow.
