Jaynes argument is roughly as follows: Consider how you would react to being shown evidence of, eg ESP or faith healing. I (for example) simply have a weaker

Jaynes argument is roughly as follows: Consider how you would react to being shown evidence of, eg ESP or faith healing. I (for example) simply have a weaker prior belief in the possibility of faith healing than the possibility of being convincingly lied to. So being shown evidence of faith healing makes me very suspicious rather than causing me to believe in it. This is rational (given the my prior belief weighting).