A machine can now not only beat you at chess, it can also outperform you in debate. Last week, in a public debate in San Francisco, a software program called Project Debater beat its human opponents, including Noa Ovadia, Israel's former national debating champion.

Brilliant though it is, Project Debater has some weaknesses. It takes sentences from its library of documents and prebuilt arguments and strings them together. This can lead to the kinds of errors no human would make. Such wrinkles will no doubt be ironed out, yet they also point to a fundamental problem. As Kristian Hammond, professor of electrical engineering and computer science at Northwestern University, put it: "There's never a stage at which the system knows what it's talking about."

What Hammond is referring to is the question of meaning, and meaning is central to what distinguishes the least intelligent of humans from the most intelligent of machines. A computer works with symbols. Its program specifies a set of rules to transform one string of symbols into another. But it does not specify what those symbols mean. Indeed, to a computer, meaning is irrelevant. Humans, in thinking, talking, reading and writing, also work with symbols. But for humans, meaning is everything. When we communicate, we communicate meaning. What matters is not just the outside of a string of symbols, but the inside too, not just how they are arranged but what they mean.

Meaning emerges through a process of social interaction, not of computation, interaction that shapes the content of the symbols in our heads. The rules that assign meaning lie not just inside our heads, but also outside, in society, in social memory, social conventions and social relations. It is this that distinguishes humans from machines. And that's why, however astonishing Project Debater may seem, the tradition that began with Socrates and Confucius will not end with artificial intelligence.

    When "Rise of the Planet of the Apes" was first shown to the public last month, a group of excited animal activists gathered on Hollywood Boulevard. But they weren't there to throw red paint on fur-coat-wearing film stars. Instead, one activist, dressed in a full-body monkey suit, had arrived with a sign praising the filmmakers: "Thanks for not using real apes (猿)!"

    The creative team behind "Apes" used motion-capture (动作捕捉) technology to create digitalized animals, spending tens of millions of dollars on technology that I records an actor's performance and later processes it with computer graphics to create a final image (图像). In this case, one of a realistic-looking ape.

    Yet "Apes" is more exception than the rule. In fact, Hollywood has been hot on live animals lately. One nonprofit organization, which monitors the treatment or animals in filmed entertainment, is keeping tabs on more than 2,000 productions this year. Already, a number of films, including "Water for Elephants," "The Hangover Part Ⅱ" and "Zookeeper," have drawn the anger of activists who say the creatures acting in them haven't been treated properly.

    In some cases, it's not so much the treatment of the animals on set in the studio that has activists worried; it's the off-set training and living conditions that are raising concerns. And there are questions about the films made outside the States, which sometimes are not monitored as closely as productions filmed in the Sates.

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    This month, Germany's transport minister, Alexander Dobrindt, proposed the first set of rules for autonomous vehicles(自主驾驶车辆). They would define the driver's role in such cars and govern how such cars perform in crashes where lives might be lost.

    The proposal attempts to deal with what some call the “death valley” of autonomous vehicles: the grey area between semi-autonomous and fully driverless cars that could delay the driverless future.

    Dobrindt wants three things: that a car always chooses property(财产) damage over personal injury; that it never distinguishes between humans based on age or race; and that if a human removes his or her hands from the driving wheel — to check email, say — the car's maker is responsible if there is a crash.

    “The change to the road traffic law will permit fully automatic driving,” says Dobrindt. It will put fully driverless cars on an equal legal footing to human drivers, he says.

    Who is responsible for the operation of such vehicles is not clear among car makers, consumers and lawyers. “The liability(法律责任) issue is the biggest one of them all,” says Natasha Merat at the University of Leeds, UK.

    An assumption behind UK insurance for driverless cars, introduced earlier this year, insists that a human “ be watchful and monitoring the road” at every moment.

    But that is not what many people have in mind when thinking of driverless cars. “When you say ‘driverless cars', people expect driverless cars.”Merat says. “You know — no driver.”

    Because of the confusion, Merat thinks some car makers will wait until vehicles can be fully automated without operation.

    Driverless cars may end up being a form of public transport rather than vehicles you own, says Ryan Calo at Stanford University, California. That is happening in the UK and Singapore, where government-provided driverless vehicles are being launched.

    That would go down poorly in the US, however. “The idea that the government would take over driverless cars and treat them as a public good would get absolutely nowhere here,” says Calo.