Machines are teaching themselves to grapple with the real world

Google's AlphaGo software has defeated human Go grandmaster Lee Sedol 4-1 in a five-game series. Despite Lee coming back to win the fourth game (see page "Machine outsmarts man in battle of the decade"), for many the realisation of what was taking place was stark. "I didn't think AlphaGo would play the game in such a perfect manner," Lee admitted in shock. The showdown has drawn eyes from around the world – 30 million people watched it in China alone. Like Deep Blue checkmating chess grandmaster Garry Kasparov, or Watson answering questions on Jeopardy!, it represents a milestone in our relationship with machines.