Besides the Turing machine, Alan Turing also developed what we now call the Turing Test in Turing's seminal 1950 AI paper "Computational Machinery and Intelligence". Turing describes his imitation game and says if a judge cannot distinguish between communicating with a computer versus a human than this is an indication of that a computer "thinks".
It's not clear exactly when a computer will pass the Turing Test but with systems like Watson and Siri we are getting very close. One can imagine that if we run the right machine learning algorithms on large data sets like Facebook chats or text messages, we can create a system that would fool most people. But would it really be intelligent?
Think about how Google translate works. There is no understanding of the meaning of the words in either language, just a statistical approach to develop a function that maps one language into another. Is this method really intelligence, are Google's computers "thinking"? Not really.
In a couple of years it will be clear that computers easily pass the Turing test. It will be another milestone, like beating humans at Chess and Jeopardy. The computers won't be any more intelligent by passing the test but they will be more useful. And I'll take useful over intelligent any day.