&gt; <i>Argument from authority is not invalid when it can be backed with fact.</i><p>Your line of argumentation doesn&#x27;t make sense here. We can look for backing up an authority with facts which come from...that same authority, who we then have to believe or not, short of replicating their study. Or we can get someone else to replicate the study, and someone else to replicate that study, and...suddenly we&#x27;re talking about scientific consensus again.<p>You do not have time to replicate and verify the work of every scientist. At some point you are going to have to choose to take some authority&#x27;s word for it.