A common and very dangerous misconception often seen on the Internet is the idea that a childhood immunization, the MMR vaccine, causes autism. This is completely false, but began when a man published a falsified and now discredited paper making that claim. He was later found to have received money from lawyers representing parents of children with autism who wanted to sue the vaccine companies. Which criterion of critical thinking is most clearly being violated by those who accepted the false claim?

Authority or claimed expertise does not make something true.

All evidence is not equal in quality.

Very few "truths" do not need to be tested.

Keep an open mind.