In a 1950 article, Alan Turing defined what is now known as the Turing Test.

In it, he proposed a test in which a human “converses” with two entities — one human and one computer program — over a text-only channel (such as a computer keyboard and display), and then attempts to determine which is the human and which is the computer.

If after, say, five minutes of testing, the majority of human interrogators are unable to determine which is which, Turing said that we could claim the computer system has achieved a certain level of intelligence.

Two recent advances have dramatically enhanced interest: the ready availability of many terabytes of data, from technical documents on every conceivable topic to the growing personal databases of “lifeloggers”; and sophisticated statistical (computational and mathematical) techniques for organizing and classifying this data.

So far no computer system has passed the Turing test, according to the strict rules of the Loebner Prize competition, but they are getting close. The 2010 and 2011 competitions were won by a chat-bot computer system known as “CHAT-L,” by artificial-intelligence programmer Bruce Wilcox. In 2010 this program actually fooled one of the four human judges into thinking it was human.

All this raises the question of whether a computer system that finally passes the Turing test is really “conscious” or “human” in any sense.

These issues were summarized by the University of Bourgogne’s Robert M. French in a recent Science article: “All of this brings us squarely back to the question first posed by Turing at the dawn of the computer age, one that has generated a flood of philosophical and scientific commentary ever since.

“No-one would argue that computer-simulated chess playing, regardless of how it is achieved, is not chess playing. Is there something fundamentally different about computer-simulated intelligence?”

French is among the more pessimistic observers. Others, such as the American futurist Ray Kurzweil are much more expansive.

He predicts that in roughly the year 2045, machine intelligence will match then transcend human intelligence, resulting in a dizzying advance of technology that we can only dimly foresee at the present time — a vision outlined in his book The Singularity Is Near.

Only time will tell when Turing’s vision will be achieved. But civilization will never be the same once it is.