The literature says that contradictory evidence only fuels conspiracy theories: it proves how deep the conspiracy goes, and how many people are in on it. The Dunning-Kruger effect says that the less proficient one is in their knowledge of a topic, the higher they rate their expertise. Confirmation bias describes how people accept weak evidence that agrees with their views, and reject strong contradictory evidence. Salon.com predicts that the stories about Barack Obama’s birth certificate will never die. I’ve been astounded, seriously astounded by the language I have seen here and elsewhere expressing confident knowledge of utter poppycock (stronger words may be substituted by the reader).
Logical argument and evidence have been largely ineffective. (That shouldn’t be surprising. Anyone who bought in to the birther world view has already demonstrated deficiency in logical argument and the evaluation of evidence.)
Is there anything to be done?
I think the answer lies not in argument or evidence, but in remedial education. The problem is that folks need to improve their critical thinking skills, their knowledge of valid argument forms, their ability to evaluate evidence, their familiarity with common propaganda techniques and, in our limited case, their understanding of how the law works. Teach birthers how to think, not what to think.