Doubt is Their Product is the focus of the second piece in a three-part series by Slate’s Daniel Engber on “radical skepticism and the rise of conspiratorial thinking about science.” After describing the strategy of manufacturing doubt, from its tobacco-industry roots to its use by energy and drug companies and politicians, Engber suggests that anti-regulatory forces aren’t the only ones using it. His perspective is an interesting and useful one for those of us who are immersed in the scientific back-and-forth and might not realize how the general public views the issues.

In the first in his three-part series, Engber profiles “zealous skeptic” David Berlinski, who makes a point of emphasizing all of the things science doesn’t know – but who, unlike the familiar religious and fossil-fuel forces claiming that scientists haven’t “proven” evolution or global warming, does so without having a stake in these big issues. In his second piece, Engber describes several of the lessons from Doubt is Their Product, and links the doubt-sowing approach of industry and politicians to that of Berlinski. He then goes on to accuse advocates of the precautionary principle of using the same tactics:

Meanwhile, environmental activists draw from their own ample reservoir of skepticism. If private industry can bewitch the government with contrarian science, so, too, can they. The greens pursue an equal-but-opposite approach: They warn of hidden dangers and put uncertainty in the mind of the consumer. If the PR flacks says there’s no proof that beryllium is a carcinogen, the activists point out there’s no proof it isn’t. Doubt is their product, too, in the form of the “precautionary principle.”

According to this moral and political dictum—which, like all visionary environmental legislation, has been embraced in the past few years by the European Commission and the city of San Francisco—the manufacturer of a new technology carries the sole burden of proving its safety. So if you wanted to introduce a genetically engineered crop into the wild, you’d first have to demonstrate, beyond any possible doubt, that it does no harm. That sounds reasonable enough. But let’s say your crop had the potential to feed thousands or millions of people? If the precautionary principle were law, someone who wanted to stop you from sowing this golden rice would only have to produce the whisper of uncertainty and the suggestion that more studies were needed.

Thus the eco-advocacy groups play Big Tobacco’s game: They call for data and rest their case. The Center for Science in the Public Interest alleges that diet sodas are a health hazard and modestly claims that “questions have been raised about the safety of aspartame.” The Center for Food Safety says of animal cloning, “[N]ot enough research has been done”; of GMOs, they “could pose serious risks”; of food irradiation, it “can do strange things” that “scientists still do not fully understand”; and so forth. These scare tactics may be venerable, but the vigor with which they’re now pursued—and the scientific language used to promote them—owes something to the success of the corporate style.

Indeed, at this point it may be entirely rational to be suspicious of mainstream science. Since 1999, Congress has served up two industry-friendly laws—the Data Access Act and the Data Quality Act—that make it easier to hamstring legitimate research. At the same time, pharmaceutical companies conduct 70 percent of all our clinical drug studies and pay half the operating budget of the Food and Drug Administration. Universities own and sell patents derived from federal grants. Science journals rarely publish negative results, but they do run pages of industry advertisements. With all this room for doubt, it’s hard to blame an outsider for throwing up his hands—just what do we know about anything?

For someone like me, who’s familiar with a lot of the science and the advocacy efforts around these issues, this is a strange connection to claim, because there’s little similarity between fuel-industry efforts to claim global warming uncertainty and the work of environmental groups that advocate for the use of the precautionary principle. There’s a big difference between genuine uncertainty – which often exists in the early stages of research about a particular substance or health threat – and the manufactured uncertainty of companies commissioning studies that are designed from the start to exonerate a product.

There’s also a difference between scientific uncertainty and policy debates. For instance, it’s well established that GM crops will spread pollen that can mix with non-GM crops. The debate is not about whether mixing will happen, but about whether the potential rewards are worth the risks. Most environmental advocates don’t invoke the precautionary principle indiscriminately, but urge its use when there’s some evidence that a substance might affect human health. (In Doubt, David does disagree with some advocacy uses of the precautionary principle, such as anti-food-irradiation campaigns.)

Engber shows us that an outsider doesn’t necessarily grasp these distinctions. When people throw up their hands and decide not to pay attention to any more “scientific debates,” it becomes harder to have the conversations about risks and benefits that we ought to be having. The more people turn away from engaging in science-related issues, the easier it is for manufacturers of doubt to advance their agendas.