From Hello Scienceblogs

Denialism is the employment of rhetorical tactics to give the appearance of argument or legitimate debate, when in actuality there is none. These false arguments are used when one has few or no facts to support one’s viewpoint against a scientific consensus or against overwhelming evidence to the contrary. They are effective in distracting from actual useful debate using emotionally appealing, but ultimately empty and illogical assertions.

Examples of common topics in which denialists employ their tactics include: Creationism/Intelligent Design, Global Warming denialism, Holocaust denial, HIV/AIDS denialism, 9/11 conspiracies, Tobacco Carcinogenecity denialism (the first organized corporate campaign), anti-vaccination/mercury autism denialism and anti-animal testing/animal rights extremist denialism. Denialism spans the ideological spectrum, and is about tactics rather than politics or partisanship.

From Hello Scienceblogs

Via Denialism: It’s a tactic, not an ideology and Skepchick