The complexity of the world makes reasoning about it very difficult. In many public deliberations it can be useful if this situation can be made even more incomprehensible. There are many ways to bring this about. One effective way to do is to engage professionals to develop campaigns to increase public ignorance. In the United States the tobacco lobby effectively kept damaging information about the lethality of their product the people. They also systematically claimed that there was no "proof" of the link. More recently climate change denial campaigns have been developed that are intentionally designed to sow doubt in the population.
"In a now-famous memo, leaked to the press in 2003, Republican pollster and media advisor Frank Luntz urged candidates in the 1992 mid-term elections to use scientific uncertainty as a political tactic. "The scientific debate remains open" he wrote emphatically. "Voters believe that there is no consensus about global warming. Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly. Therefore, you need to continue to make the lack of scientific certainty a primary issue in the debate." (Oreskes and Conway)
How it Works
According to Wikipedia, Agnotology "is the study of culturally induced ignorance or doubt, particularly the publication of inaccurate or misleading scientific data."
Oreskes, Naomi and Conway, Erik. Challenging Knowledge: How Climate Science Became a Victim of the Cold War. In Agnology
Proctor, Robert. Agnotology: The Making and Unmaking of Ignorance.