
Imagine a robot that has a limited number of responses. If you say hello to it, the robot automatically reacts with: “Hi, how are you today?” If you keep greeting the robot, the repeated response would get annoying and it would not take long for you to recognise it as a machine. But say the creator programs it so that at every third time someone greets the robot, it changes its response to a second sentence: “Fine day, isn’t it?” In this case you would take longer to catch on it was a robot, but not much longer.






We need a new climate philosophy, says Pachauri. Photograph: Ed Wray/AP