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.

The Government's sugar tax on soft drinks has brought in half as much money as Ministers first predicted it would generate, the first official data on the policy has shown.

First announced in April, 2016, the tax which applies to soft drinks containing more than 5g of sugar per 100ml, was introduced to help reduce childhood obesity（肥胖）. It is believed that today's children and teenagers are consuming three times the recommended level of sugar, putting them at a higher risk of the disease.

Initially the sugar tax was expected to make £520m a year for the Treasury. However, data of the first six months showed it would make less than half this amount. At present it is expected to generate £240m for the year ending in April 2019, which will go to school sports.

It comes after more than half of soft drinks sold in shops have had their sugar levels cut by manufacturers（制造商）so they can avoid paying the tax. Drinks now contain 45 million fewer kilos of sugar as a result of manufacturers' efforts to avoid the charge, according to Treasury figures. Since April drinks companies have been forced to pay between 18p and 24p for every litre of sugary drink they produce or import, depending on the sugar content.

However, some high sugar brands, like Classic Coca Cola, have accepted the sugar tax and are refusing to change for fear of upsetting consumers. Fruit juices, milk-based drinks and most alcoholic drinks are free of the tax, as are small companies manufacturing fewer than 1m litres per year.

Today's figures, according to one government official, show the positive influence the sugar tax is having by raising millions of pounds for sports facilities（设施）and healthier eating in schools. Helping the next generation to have a healthy and active childhood is of great importance, and the industry is playing its part.

    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.