The Wellcome Trust is not making any kind of threat. That would be vulgar. The trust is a unique institution that has helped to fund much of the worthwhile scientific research in the UK over the last 20 years. Without its annual £1bn investment in research, nearly all of which is spent in the UK, there would be a lot less world-class science in this country. Its open letter to the leaders of all political parties explaining that it may have to reconsider its funding if the post-Brexit order is inimical to scientific research is simply a helpful clarification of reality for a government that may not wholly have grasped some of the implications of some of its own rhetoric. Not a threat at all. Yet two possible consequences of a hard Brexit are singled out in the trust’s letter as potentially fatal to the health of first-rate science in the UK: a withdrawal from European cooperation, and – perhaps more obvious – a clampdown on visas for foreign researchers of any age and achievement, and their families.

Both of those measures might appeal to the atavistic xenophobia which has gripped large sections of the Conservative party and indeed of the country as a whole. The crisis of science funding, and of faith in science more generally, is part of the wider contemporary rebellion against conspicuous elites. Considered sociologically, science is the embodiment of the transnational elitism that voters everywhere have revolted against in the last year. The scientist claims to know better than the rest of us; what makes this claim more aggravating is that it is often accompanied by the belief that everyone else ought to be able to understand scientific reasoning and if we can’t this must be the result of moral or intellectual deficiency. This has drawn science into the culture wars in the US and to some degree in Britain, and on that battlefield most scientists are helpless. To hold up a placard saying, “Without science it’s just fiction”, is to make a joke that your own side will appreciate and be warmed by. But outsiders can see that slogan is not itself scientific and so on its own terms fiction.

What complicates the story is that the scientists are in fact vitally right about the non-human world. On climate change, their message is both true and more urgent than almost anything else except the threat posed by nuclear weapons.

They have a great deal more to be proud of, too. Almost all the improvements we need to make in the world, and almost all our defences against things getting worse, depend on scientific understanding and have done so for the last 200 years. But the advances of science are no use – or harm – to anyone on their own. It is not enough to understand the world. The point is to change it. And that requires all the skills of politics and of cultural warfare that some scientists shun and many believers in science practise rather badly.

The recent march for science and march against climate change have both highlighted really important causes which we should all support. The Wellcome Trust’s letter lays out objective truths about the conditions necessary for science to flourish. The government here and still more in the US must respect science, and the judgment of scientists. But for that to happen there will need to be political sophistication as well as political force on the part of all the supporters of enlightenment.

• This article was amended on 1 May 2017. An earlier version said the Wellcome Trust had helped to fund “almost every worthwhile piece of scientific research in the UK over the last 20 years”, and that without its research funding “there would be very little world-class science in this country”.