Waldo insists that immunization vaccines cause autism, even though he knows that there is no credible scientific evidence to support that claim. this is an example of

Waldo's opinion is an example of a stubborn refusal to abandon a discredited position. Such a refusal is often an example of prejudice and/or biased thinking. Because there is evidence to disprove the claim, and Waldo knows about it, his position can no longer be considered logical or valid.