If you get advice from someone you thought had good believability and it turns out that it wasn't the best advice, you might assume that your reading of believa

If you get advice from someone you thought had good believability and it turns out that it wasn't the best advice, you might assume that your reading of believability was wrong. Similarly, what if someone you thought wasn't believable turns out to be? I feel this technique just shifts the problem away from assessing the truthfulness/utility of advice, into assessing the believability of the person providing it. I'm not sure the latter is easier or more likely for you to be accurate in that assessment over the former. And I feel moving to assessing believability puts you at a greater risk of believing bullshitters, sharlatans and manipulators. Where as analyzing their advice or information from a framework of truth might be more resiliant to those and can help you detect those scenarios. And I think this is kind of the issue with ad-hominem, though I think ad-verecundiam is the more accurate fallacy that applies. You could falsely believe someone to be believable by relying on a test that believes those who appear to have more expertise or authority.