Scientific doubt was first articulated as a political strategy in 1969 by tobacco executives in an infamous memo that contained the phrase “doubt is our product” (Oreskes and Conway 2010 , 34). The tobacco industry sought to cast doubt on the rapidly mounting evidence that linked their product to cancer and other diseases. They believed that focusing attention on uncertainty about the causal connections between tobacco and disease was “the best means of competing with the ‘body of fact’ that exists in the minds of the general public” (34). “The tobacco industry’s key insight [was] that you could use normal scientific uncertainty to undermine the status of actual scientific knowledge” (34). The tobacco companies organized public relations campaigns that cast doubt on the status of scientific knowledge by distorting the inherent uncertainty that comes with empirical research. Other, more earnest groups have also used scientific doubt as a policy wedge for philosophical and ideological motivations.

There are highly motivated groups who oppose childhood vaccination programs out of fear that vaccinations pose a health risk to children. Some in the anti-vaccination movement have taken the radical position that germ theory and immunization have had no benefits and have caused much illness and disease. It is true that vaccination comes with statistical risks. Yet there are enormous quantities of data, collected over decades, that demonstrate that the benefits of immunization greatly outweigh the risks. Despite the quantity and quality of evidence, the anti-vaccination movement has had a significant impact on public policy by casting doubt on the status of scientific knowledge.

While fear is an important driver of the anti-vaccination movement, to an important extent it is also driven by ideology. Many anti-vaccination activists adhere to alternative conceptions of health and disease that are opposed to the dominant biomedical model (Ernst 2001 ). Disease is often characterized as an imbalance of bodily conditions resulting from lifestyle choices, rather than placing the emphasis on invading microorganisms. Opponents of childhood vaccinations commonly recommend alternative therapies, such as homeopathy, chiropractics, and naturopathy as more effective and less risky than vaccination (Kata 2010 ). Rather than technical notions of risk, these groups focus on unknowns and uncertainties to cast doubt on vaccination programs. A common strategy is to focus on ignorance of the body and health and to argue that widespread technological interventions into these poorly understood systems could be creating numerous as of yet unknown health problems (Hobson-West 2007 ). For example, various people have argued that it is not known whether universal vaccination programs create numerous health problems, from autism to arthritis to AIDS, because scientists are not looking for these connections. This type of argument follows the general form of an argument from ignorance, a form of argument that is widely used by opponents of technological interventions into complex systems. It is argued that by tinkering with complex and incompletely understood systems scientists could introduce numerous and unknown health and environmental risks. These types of arguments are not completely without merit. Nonetheless, they are easily open to abuse. Importantly, distorting and misrepresenting the degree of ignorance and level of uncertainty associated with the risks and benefits of childhood vaccinations has put children in danger and created public health risks.

The disproportionate impact of the anti-vaccination movement has been attributed to the ability of small groups of motivated individuals to spread their message on the Internet. In one study of anti-vaccination websites, all but one “contained arguments against vaccination that could be considered disingenuous” (Kata 2010 , 1714). The democratization of information through the Internet is overall a positive development, but it has come with costs. “With the large number of self-styled experts online, even the most respected vaccine authority’s advice becomes just another opinion” (1715). Ironically, the increase of information leads to a leveling that can make informed decision making more difficult. Science no longer has the authority it once had in public deliberations. This changes the relationship between scientific experts and the public in important ways. A central message of the anti-vaccination movement’s ideology is that parents have a moral responsibility to be freethinkers and challenge the dominant medical establishment. Trust in the scientific establishment is painted as a vice and doubt as a virtue.

The climate change skeptic movement is an example where scientific doubt has been used for closely linked ideological and economic motivations. Anthropogenic climate change is uncontroversial among climate scientists but remains controversial among US politicians and the larger public. This stems at least in part from the efforts of climate skeptic groups. Numerous conservative think tanks have been the driving force behind the climate skeptic movement. These thank tanks have held conferences, created blogs and websites, and published numerous books that have strategically distorted the uncertainty inherent in knowledge of global climate change (McCright and Dunlap 2003 ; Dunlap and Jacques 2013 ).

The tactics used by these groups is to argue that the climate threat has been greatly exaggerated, that climate science is largely uncertain, and that scientists are politically motivated (McCright and Dunlap 2003 ; Oreskes and Conway 2010 ). Once again, a healthy suspicion that challenges scientists is always needed. The problem is that some conservative think tanks’ suspicions are motivated by political ideology. In general, conservative think tanks adhere to a philosophy that seeks to promote the general welfare through economic growth. They are convinced that environmental regulations in general, and regulations of greenhouse gases in particular, are an obstacle to wealth creation. Hence, such regulations harm the general welfare and are counterproductive. For example, one of the leading climate skeptic think tanks is the Heartland Institute. The Heartland Institute is committed to increasing the influence of libertarian philosophy and principles on pubic policies. This commitment has led them to mount a campaign to create doubt about the claims of mainstream climate science. From their view the political solutions being offered to combat global warming are part of a larger liberal agenda of increasing government regulations. Government efforts aimed at addressing climate change, such as a carbon tax, run counter to their philosophy of limited government and free-market individualism. Casting doubt on the science of climate is seen as an effective strategy for demonstrating that such policies are not necessary.

Interestingly, while climate skeptics are often at the opposite end of the political spectrum from anti-vaccination activists, who tend to be more liberal, they use similar strategies. Both groups distort and misrepresent scientific uncertainty to support a political agenda. This fact points to the idea that neither conservatives nor liberals are necessarily antiscience, as has sometimes been charged. Instead, many groups, regardless of political leanings, have recognized the utility of using the inherent uncertainty in science as a political strategy to advance their particular cause. This tactic can potentially create grave public health and environmental risks by delaying needed action.

The widespread use of scientific doubt as a political strategy poses many practical and ethical problems for decision making. One particularly important area of ethical research involves the relationship between science, trust, public discourse, and democratic decision making. Illegitimately casting doubt on well-supported scientific evidence can undermine public trust in science. Citizens must make judgments about difficult issues involving science and technology with incomplete knowledge and numerous uncertainties. The public is in a situation in which to some extent they must be able to trust scientists. Trust has been characterized as situations in which actors are willing to bracket off uncertainties. Science and technology are playing an ever-increasing role in the modern world. Illegitimately undermining trust in science could lead to bad decisions with tragic consequences. The many uses of scientific doubt as a political tool need more serious treatment by ethicists.