You could argue about how I’ve split or lumped these, but in essence, that’s a lot of goals.

They also differ substantially in content and approach. Some feel oppositional; others, celebratory. Some use language that would not be out of place in a science fair; others use the rhetoric of protests. Many directly contradict statements that the march “is not a political protest” (from its own organizers), or that it is “not about scientists or politicians” (from its own mission page). It is clearly about all of these things.

“I think the organizers need to come up with two or three top messages that they want to really drive home,” says Maureen Boyle at the National Institute on Drug Abuse, who will be marching in DC. “And that needs to be framed around the current problem in society – the denial of evidence, and the denial of facts.” Boyle, a neuroscientist who now works in the highly contentious area of drugs policy, is keenly aware that translating scientific evidence into policy decisions is no easy task. But “we need to at least be starting at the same baseline,” she says.

That is hard when the administration denies that climate change exists, courts the anti-vaccine community, and favors legislation that could effectively displace scientific evidence from the policy-making process. Meanwhile, the President and his staff regularly state easily disproven falsehoods, billing them as “alternative facts” and dismissing contradictory evidence as “fake news”. “There’s no such thing anymore, unfortunately, as facts,” said one surrogate.

If there is one issue that unites the marchers, scientist or non-scientist, Democrat or Republican, that’s it—the undermining of scientific evidence. “The discrediting of the scientific method is what we need to stand against,” says Caroline Weinberg, a writer and public health researcher who is co-chairing the march. “That’s the thing we most need to advocate for.”

Weinberg admits that this problem pre-dates Donald Trump’s presidency. “There’s been a slow building of science denialism in both the government and in society in the general,” she says. “A lot of people have been trying to fight it, but there hasn’t been a global organization of scientists standing up for it. And there should have been. There’s no reason I couldn’t have done this 5 years ago, but it reached a boiling point. And everyone had a different reason they were set off.”

She embraces that plurality, in both of the march and the marchers. “The reason why so many people have become enthusiastic is that it’s not specific to climate change or vaccinations, genetics or physics,” she says. “It’s a march for science in general, and everyone has a part of that to connect to.” Consider the march’s Facebook group, with its 838,000 members and counting. In just the last few days, people have posted that they are marching: in defense of evidence; for cures to diseases; in support of people from disadvantaged backgrounds who want to be scientists; for their students; and to protect land, air and water. “I march for fungi,” wrote one member. “Censorship of scientists is why Krypton exploded,” said another.