A second, detailed reading might make it seem like this comment’s has an error. However, the reasoning is sound; “you said the coin was heads” doesn’t distinguish very well between “the coin was heads” and “the coin was tails but you lied about the bet”, so doesn’t provide much evidence.
Likewise, the dismissing of hearsay appears to be an error, but remember that humans have finite computational power. If you take into account (at least) the hypothesis that somebody’s trying to deceive you about reality, you effectively end up dismissing the evidence anyway – but then you need to keep track of an extra hypothesis for the rest of your life to avoid scatterings of hearsay consistently nudging up your probability estimate when that’s not really founded. (This is assuming that it’s cheap to manufacture hearsay; expensive-to-manufacture hearsay shouldn’t be dismissed so lightly.)
A second, detailed reading might make it seem like this comment’s has an error. However, the reasoning is sound; “you said the coin was heads” doesn’t distinguish very well between “the coin was heads” and “the coin was tails but you lied about the bet”, so doesn’t provide much evidence.
Likewise, the dismissing of hearsay appears to be an error, but remember that humans have finite computational power. If you take into account (at least) the hypothesis that somebody’s trying to deceive you about reality, you effectively end up dismissing the evidence anyway – but then you need to keep track of an extra hypothesis for the rest of your life to avoid scatterings of hearsay consistently nudging up your probability estimate when that’s not really founded. (This is assuming that it’s cheap to manufacture hearsay; expensive-to-manufacture hearsay shouldn’t be dismissed so lightly.)