Several days ago, evolutionary biologist Jerry Coyne wrote a post titled “Nature editor Henry Gee goes all anti-science.” How did Gee go all anti-science? He wrote this:

The problem is that we (not the royal we, but the great unwashed lay public who won’t know the difference between an eppendorf tube and an entrenching tool) are told, very often, and by people who ought to know better, that science is a one-way street of ever-advancing progress, a zero-sum game in which facts are accumulated and ignorance dispelled. In reality, the more we discover, the more we realise we don’t know. Science is not so much about knowledge as doubt. Never in the field of human inquiry have so many known so little about so much.

Deep but sensible. So why get worked up? Coyne drops a hint:

Yes, further knowledge raises yet more questions that we hadn’t realized, but that doesn’t mean that some questions don’t get answered. A water molecule has two hydrogen atoms and one oxygen atom. The earth is about 4.6 billion years old. Our closest living relative is the chimpanzee. The continents move, traveling on plates.

Wait.
In chemistry class, the answer to “what is water?” would be “two hydrogen atoms and one oxygen atom.” But if you’re not in chemistry class, the expected answer might be something else. For any question, the answer depends on who is asking, who is answering, and why — among other things.
Gee’s notion — illustrated above — that even the firmest bits of scientific knowledge are socially constructed, incomplete and revisable really bugs Coyne. Fortunately, Coyne can console himself with a neat theory of truth:

Yes, science is about doubt and knowledge, and some of that knowledge, while not true in the philosophically absolute sense, is true in the only sense that matters: you’d bet all your fortune on its being right.

So what’s true? Coyne says it’s what you’d bet on being right. But what’s “right”? Coyne doesn’t say, which is just as well. This theoretical stuff goes in a loop or down a rabbit hole real fast.
Importantly, Gee did not say science is “about doubt and knowledge.” Rather, Gee said, in a typically British, understated way, that science “is not so much about knowledge as doubt.” Big difference.
But if the primary business of science is to doubt rather than know, then how can science popularizers use science to influence policy and public opinion? Circumspection may be the most scientific attitude but it does not inspire bold political action.