Many scientists have found it incredible in recent years that their conclusions about empirical topics are being questioned by those who feel free to disagree with them based on nothing more than gut instinct and ideology. This is irrational and dangerous. Denialism about evolution, climate change, and vaccines has been stirred up in recent years by those who have an economic, religious, or political interest in contradicting certain scientific findings. Rather than merely wishing that particular scientific results weren’t true, these groups have resorted to a public relations campaign that has made great strides in undermining the public’s understanding of and respect for science. In part, this strategy has consisted of attempts to “challenge the science” by funding and promoting questionable research – which is almost never subject to peer review – in order to flood news outlets with the appearance of scientific controversy where there is none. The result has been a dangerously successful effort to subvert the credibility of science.