Donald Trump probably won’t destroy American democracy if he’s re-elected. It’s been ailing for some time, but has deep roots. It will most likely take more than one presidential term to finish it off.

But he is, nevertheless, set to move us farther down that path. Mr. Trump and others like him have been hollowing out our system of government bit by bit for many years. They operate by exploiting a weakness that all democracies share.

Democracy is unnatural. It’s the child of the Scientific Revolution that arose only a few hundred years ago, bringing with it new and unnatural ways of thinking and acting. Mr. Trump’s enemy, boiled down to its core, is science.

Jonathan Sallet, writing for the Brookings Institution on March 8, 2017 at brookings.edu, examined democracy’s connection to science. He argued that the American Revolution of 1776 was the product of “a chain reaction” that began with the appearance of modern science almost two centuries before.

David Wooton, in his book, “The Invention of Science,” provides some background for that claim. The Scientific Revolution, he says, caused the mental world of educated people to change, “more rapidly than at any time in previous history, and perhaps than at any time before the 20th century.”

The mental world before the Scientific Revolution would have been a comfortable one for Mr. Trump. It relied on religion and tradition. People judged the truth of a proposition by how well it fit into those frameworks.

There was no urge to test the idea that a goat’s blood will soften diamonds. And if the Earth was the center of the universe, as the Church taught, Galileo’s telescope lied when it said otherwise. People accepted ideas if they were consistent with their basic beliefs, and there was no further need to prove them.

It had been that way since the beginning of history and before. Science replaced that ancient way of thinking with something new and unnatural — the scientific method. With that was born Mr. Trump’s most dangerous opponent, facts.

Mr. Wooton informs us that facts didn’t exist, either as a word or a concept, before science. They, and science itself, were only possible after the invention of the printing press, which allowed people to share and test observations about the real world. With the arrival of science and facts, ideas had to conform to reality instead of the other way around.

The founders created our republic from within that new worldview. They believed that a political system had to conform to natural laws revealed by reasoning about the facts. Democracy is built on facts, and can’t survive without them.

Mr. Trump represents a return to an earlier way, rooted deep in human psychology. A proposition is true, in this pre-scientific mindset, if it conforms to deeply-held beliefs. The comedian Stephen Colbert called it “truthiness,” a reliance on opinions that come “from the gut” instead from facts.

Mr. Trump insists, for example, that immigrants are mostly criminals. Research studies, including one published in July of 2023 (Ran Abramitzky and colleagues, nber.org) shows that they instead have a much lower crime rate than white Americans. Those results are — as with Galileo and his telescope — irrelevant or a lie when viewed through the lens of truthiness.

Mr. Trump is famous for his reliance on statements that have no basis in fact. Fact-checker Media Bias/Fact Check awards him the lowest possible rating “due to an extraordinary number of failed fact-checks and false claims.” Mr. Trump’s falsehoods are remarkable not just for their frequency but for their mind-boggling detachment from reality, as when he insisted years ago that President Obama wasn’t a citizen of the United States.

His failure to tell the truth isn’t merely a personal shortcoming, but instead an essential part of his political strategy. The path to power for politicians like Mr. Trump runs through a return to a world in which there are no facts, but only propositions that are emotionally appealing. It’s a place in which democracy, the child of science, can’t exist.

The essence of the danger that Mr. Trump represents isn’t in his policies. We could always reverse them at the next election in a democracy. But democracy, with its free and fair elections, is irreversibly fused with science and its belief in the existence of facts.

Mr. Trump’s candidacy is, at its heart, a rejection of science — and of democracy itself.

Lowell Harp is a retired school psychologist who served school districts in Ogle County. His column runs monthly in The Ogle County Life. For previous articles, you can follow him on Facebook at http://fb.me/lowellharp.