Comment by Martin Rees

But my theme is that in this century, not only has science changed the world faster than ever, but in new and different ways. Targeted drugs, genetic modification, artificial intelligence, perhaps even implants into our brains, may change human beings themselves. And human beings, their physique and character, has not changed for thousands of years. It may change this century. It's new in our history. [...] But they will have a dark side. In our interconnected world, novel technology could empower just one fanatic, or some weirdo with a mindset of those who now design computer viruses, to trigger some kind on disaster. Indeed, catastrophe could arise simply from technical misadventure -- error rather than terror. And even a tiny probability of catastrophe is unacceptable when the downside could be of global consequence.