The denialist conspiracy of the cigarette industry was crucial in this context, since science was one of the instruments used by Big Tobacco to carry out its denial (and distraction) campaign. Cigarette makers had met at the Plaza Hotel in New York City on Dec. 14, 1953, to plan a strategy to rebut the evidence that cigarettes were causing cancer and other maladies. The strategy was pure genius: The claim would be that it had not been “proved” that cigarettes really cause disease, so there was room for honest doubt. Cigarette makers promised to finance research to get to the truth, while privately acknowledging (in a notorious Brown & Williamson document from 1969) that “Doubt is our product.”

For decades thereafter, cigarette makers poured hundreds of millions of dollars into basic biomedical research, exploring things like genetic and viral or occupational causes of cancer — anything but tobacco. Research financed by the industry led to over 7,000 publications in peer-reviewed medical literature and 10 Nobel Prizes. Including consulting relationships, my research shows that at least 25 Nobel laureates have taken money from the cigarette industry over the past half-century. (Full disclosure: I’ve testified against that industry in dozens of tobacco trials.)

Now we know that many other industries have learned from Big Tobacco’s playbook. Physicians hired by the National Football League have questioned the evidence that concussions can cause brain disease, and soda sellers have financed research to deny that sugar causes obesity. And climate deniers have conducted a kind of scavenger hunt for oddities that appear to challenge the overwhelming consensus of climate scientists.

This latter fact might be little more than a historical quirk, were it not for the fact that we’ll soon have a president whose understanding of science is more like that of the people in the towns where I grew up than those scholars who taught me about Darwin and Einstein at Harvard.

We now live in a world where ignorance of a very dangerous sort is being deliberately manufactured, to protect certain kinds of unfettered corporate enterprise. The global climate catastrophe gets short shrift, largely because powerful fossil fuel producers still have enormous political clout, following decades-long campaigns to sow doubt about whether anthropogenic emissions are really causing planetary warming. Trust in science suffers, but also trust in government. And that is not an accident. Climate deniers are not so much anti-science as anti-regulation and anti-government.

Jeff Nesbit, in his recent book, “Poison Tea: How Big Oil and Big Tobacco Invented the Tea Party and Captured the G.O.P.,” documents how Big Tobacco joined with Big Oil in the early 1990s to create anti-tax front groups. These AstroTurf organizations waged a concerted effort to defend the unencumbered sale of cigarettes and petro-products. The breathtaking idea was to protect tobacco and oil from regulation and taxes by starting a movement that would combat all regulation and all taxes.