I would say it's not that he's incorrect more that he's off-topic. The changing of truth doesn't really have anything at all to do with an appeal to authority f

I would say it's not that he's incorrect more that he's off-topic. The changing of truth doesn't really have anything at all to do with an appeal to authority fallacy because said fallacy is based on the thoughts of the time. We can't possibly know how scientists are going to think 150 years from now, so we can't appeal to their authority. So while, yes, he is accurate that our knowledge of the world around us and of Science changes over time, that has nothing to do with the fallacies we're discussing.