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.

The elderly residents(居民) in care homes in London are being given hens to look after to stop them feeling lonely.

The project was dreamed up by a local charity(慈善组织) to reduce loneliness and improve elderly people's wellbeing. It is also being used to help patients suffering dementia, a serious illness of the mind. Staff in care homes have reported a reduction in the use of medicine where hens are in use.

Among those taking part in the project is 80-year-old Ruth Xavier. She said: "I used to keep hens when I was younger and had to prepare their breakfast each morning before I went to school."

"I like the project a lot. I am down there in my wheelchair in the morning letting the hens out and down there again at night to see they've gone to bed."

"It's good to have a different focus. People have been bringing their children in to see the hens and residents come and sit outside to watch them. I'm enjoying the creative activities, and it feels great to have done something useful. "

There are now 700 elderly people looking after hens in 20 care homes in the North East, and the charity has been given financial support to roll it out countrywide.

Wendy Wilson, extra care manager at 60 Pen fold Street, one of the first to embark on the project, said: "Residents really welcome the idea of the project and the creative sessions: We are looking forward to the benefits and faun the project can bring to people here."

Lynn Lewis, director of Notting Hill Pathways, said: "We are happy to be taking part in the project. It will really help connect our residents through a shared interest and creative activities."