WE ALL speak the same language, according to the linguist Noam Chomsky. A Martian scientist, he has observed, 鈥渕ight reasonably conclude that there is a single human language, with differences only at the margins鈥�.

To Earthlings, however, such differences often look anything but marginal. For some, they are barriers to be overcome. But for many others, they are borders to control and identities to be kept apart.

Following the UK鈥檚 referendum vote to leave the European Union, there were a number of incidents that raised fears about xenophobic hostility. In one, a foreign-born student was stabbed in the neck with a broken bottle after a group of men heard him speaking his native language. 鈥淥ne of them said he had a daughter living round the corner and he didn鈥檛 want her to hear us talking Polish,鈥� the victim told The Independent.

Presented with the idea that a man should use potentially lethal force to protect his child from the mere sound of a foreign language, drifting through the air on a warm summer night, the Martian scientist might reasonably decide to look farther afield for intelligent life. Earthling scientists studying languages don鈥檛 have that option. They have to create hypotheses and theories from the stuff of hotly disputed beliefs and values. Language research may need to be screened from its implications and the passions they arouse.

Researchers have devised different ways to create firebreaks between values and data. According to anthropologist Chris Knight, Chomsky鈥檚 strategy was as radical as his politics 鈥� and he developed it in order to enable himself to sustain his left-wing political commitments.

In his new book Decoding Chomsky, Knight (who mounts his own critique from a position on the radical left) argues that Chomsky needed to deny any connection between his science and his politics in order to practise both while based at the Massachusetts Institute of Technology, an institution that was heavily funded by the US military.

鈥淐homsky needed to deny any connection between his science and his politics in order to practise both鈥�

This required detaching language from society altogether. Chomsky built an idealised model of language, stripped of its social fabric and removed from the hands of the anthropologists who had traditionally provided linguistic data. 鈥淚f language could be reduced to pure mathematical form 鈥� devoid of human significance 鈥� its study could be pursued dispassionately,鈥� Knight observes, 鈥渁s a physicist might study a snowflake or an astronomer some distant star.鈥�

It takes resolve to keep this most human of faculties detached from the shared experience of being human, but Chomsky did not hesitate to deny that the raison d鈥櫭猼re of language is social. Language 鈥渋s not properly regarded as a system of communication鈥�, he declared. 鈥淚t is a system for expressing thought, something quite different.鈥� In this view of language, other people are peripheral. As far as Chomsky is concerned, says Knight, language 鈥渆xists for talking to just one person 鈥� yourself鈥�. Other workers in the field do not deny the social implications of their studies, but opt to leave them unspoken.

One of the most energetic research programmes in the science of language is investigating the possibility that bilingualism boosts the efficiency of the brain and protects it from deterioration in later life. It developed around the hypothesis that the brain of someone who knows two languages has to choose constantly between them, and that this exercise boosts its powers of control.

More recently, however, the claims of a bilingual cognitive advantage have been challenged, and it has become a conflict zone in the 鈥渞eproducibility crisis鈥� that has thrown all kinds of psychological findings into question. Now it鈥檚 not just the values that are controversial 鈥� even the facts are.

The journal Cortex published a series of papers on the row last year. Tellingly, it was the leading sceptics, Kenneth Paap at San Francisco State University, and his colleagues, who made a point of stating their belief 鈥渢hat the advantages of bilingualism across a host of personal, economic, social, and cultural dimensions overwhelmingly preponderate any disadvantages鈥�. In a follow-up article they pointed out, also tellingly, that only one contributor, Virginia Gathercole, at Florida International University, Miami, mentioned the debate鈥檚 socio-political overtones.

Their declaration showed that if you want to support bilingualism but don鈥檛 consider that your stance has a sound scientific basis, you have no option but to reveal at least a hint of your values in your scientific discourse. It also suggested a reluctance among scientists to admit even a hint of their social context.

Gathercole herself recalled how in the early 20th century, growing nationalism in the US created political pressure against bilingualism 鈥� and how researchers added to that pressure with claims that bilingualism caused 鈥渕ental confusion鈥� among immigrants. One unspoken issue in the current controversy, she observed, is 鈥渦ndoubtedly some concern鈥� that it could reverse the 鈥減ositive press鈥� bilingualism has enjoyed as a result of the claims of cognitive benefits.

Whatever the researchers鈥� concerns or intentions, the significance of the 鈥渂ilingual advantage鈥� idea is that it appears to take bilingualism out of politics. If you propose that a society benefits from having more than one language, you will provoke some resistance, resentment and rage. But if you argue that brains benefit from having more than one language, especially through reduced vulnerability to dementia, nobody could possibly counter that this is undesirable.

Improvements in health and cognitive performance are unarguably good things 鈥� and so they are politically significant, despite appearing apolitical. If they become scientifically established, they will offset the arguments of those who object to bilingualism on other grounds.

鈥淚n the early 20th century, growing US nationalism created political pressure against bilingualism鈥�

If not鈥� well, as someone who writes about science rather than actually doing it, I鈥檇 be disappointed. But I have already taken comfort from the sceptics鈥� readiness to affirm bilingualism鈥檚 advantages in other areas.

Trenchant and compelling as Knight鈥檚 critique of Chomsky is, few scientists would follow him all the way to his concluding vision of science united with revolutionary politics. But maybe it wouldn鈥檛 hurt for researchers to hint at their personal values. After all, as climate scientists know only too well, they will be suspected of bias however strictly they stick to the data.

This article appeared in print under the headline 鈥淪tand up and be counted鈥�

WHEN Poles want to wish somebody well, they wish them a hundred years of life. This is a charming prospect, as long as the chances of it coming to pass are vanishingly small. But once it starts to look as though it might actually happen, you may think that people should be careful what they wish for you.

As Lynda Gratton and Andrew Scott make arrestingly clear, it will take a lot more than good wishes to make sure that a hundred years is a blessing, not a curse.

Life expectancies have been rising by up to three months a year since 1840, and there is no sign of that flattening. Gratton and Scott draw on a to show that if the trend continues, more than half the babies born in wealthier countries since 2000 may reach their 100th birthdays.

With a few simple, devastating strokes, Gratton and Scott show that under the current system it is almost certain you won鈥檛 be able to save enough to fund several decades of decent retirement. For example, if your life expectancy is 100, you want a pension that is 50 per cent of your final salary, and you save 10 per cent of your earnings each year, they calculate that you won鈥檛 be able to retire till your 80s. People with 100-year life expectancies must recognise they are in for the long haul, and make an early start arranging their lives accordingly.

But how to go about this? Gratton and Scott advance the idea of a multistage life, with repeated changes of direction and attention. Material and intangible assets will need upkeep, renewal or replacement. Skills will need updating, augmenting or discarding, as will networks of friends and acquaintances. Earning will be interspersed with learning or self-reflection. As the authors warn, recreation will have to become 鈥渞e-creation鈥�.

鈥淢ore than half the babies born in wealthier countries since 2000 may reach their 100th birthdays鈥�

Clearly this will be expensive. As well as saving for retirement, people will need to pay for self-reflection phases and education. If you are, say, a hairdresser, you won鈥檛 need to worry too much about skills becoming obsolete. But you probably won鈥檛 be able to afford much self-renewal. Gratton and Scott point out the twofold inequality of lengthening lifespans: the rich live longer than the poor, and the better-off are better off in all the resources needed to make increasing longevity a blessing not a burden.

Even the better-off will mostly be stretched by the demands of the multistage life, though, and so the need for a good partner will loom ever larger. Although two can鈥檛 live as cheaply as one, they can live more cheaply together than apart. Crucially, too, partners will look to each other for financial cover when not earning.

There鈥檚 a contradiction here that the authors don鈥檛 really acknowledge. The 100-year life demands constant review and readiness to change one鈥檚 work and one鈥檚 self, but relies heavily on commitment to one鈥檚 partner. Yet people already review their relationships, resulting in changes of partner. They may need to reverse that policy.

Perhaps Gratton and Scott felt their groundbreaking book should skirt some of the tougher terrain, so as not to discourage readers who aren鈥檛 ready to think as boldly as they do.

The most significant absence is about ageing itself. Although they note that financial literacy declines with age, for the most part they write as though people think and feel much the same way whatever age they are. Yet recent illustrates that younger and older people have different incentives. Researchers at University College London, for example, found that older people don鈥檛 respond as strongly to rewards as younger ones. They think that may be because the 鈥渞eward鈥� neurotransmitter, dopamine, declines by up to 10 per cent every decade.

If they are still working, older people will be competing with younger people who have more motivation in their synapses. Hopefully those younger people will have the foresight to hang on to their rewards so they can pass them on to their less motivated, less competent older selves. The 100-year life will need the old to be young, and the young old.

This article appeared in print under the headline 鈥淎 hundred and counting鈥�