I’m sidestepping Fischer and Newall for a moment to focus on one instance of a fallacy that both of them seem to have overlooked. It as one type of an “appeal to authority”.
[M]ost people do not have a sufficient background in the subject to properly evaluate the evidence. Anti-Stratfordians [those questioning the authorship of Shakespeare’s plays] tend to be amateurs who have not read enough on Elizabethan theatre to see just how wildly implausible their ideas are. Let me give you an analogy. I can recognise the difference between a Yorkshire and Lancashire accent without very much trouble because I am English. I would never mistake an Irishman for a Scotsman. On the other hand, when I was living in New Jersey, I was frequently assumed to be Irish and had no idea that Californians sound different to Texans. Distinguishing accents isn’t something you tend to be taught. Rather you learn it by experience and by being immersed in a particular culture. It’s the same with history. If you have been studying a period for long enough, ideas like the anti-Stratfordians’ are as obviously incongruous as a baseball bat on a cricket pitch. (Hannam, xii)
The Latin label of that fallacy of appealing to authority is argumentum ad verecundiam. Verecundiam means shame or modesty; the idea being that an appeal to authority is an acknowledgement that the one making the argument lacks the expertise but modestly defers to another who is an expert. There is nothing modest about the above appeal, however. Yet it does demand modesty on the part of anyone who disagrees.
I found the following online explanation the most apt description where it is called Appeal to Confidence:
The arguer supports a position by appealing to himself as knowledgeable or trustworthy on the given subject, while at the same time declining to explain the actual reasons for a position. . . .
The argument appeals to confidence-building phrases, such as “trust me,” or “take it from me,” or makes an explicit claim to authority, such as “I know what I’m talking about.”
The historian who wrote that passage claiming that a historian “just knows” by being immersed in the field what is a valid argument and what is not is James Hannam (also author of God’s Philosophers). The difference between a valid and invalid idea cannot always be taught? That’s what he is saying there and it is perhaps relevant that he is not speaking of those who question whether Shakespeare wrote his plays but whether Jesus existed or not. The passage is from James Patrick Holding’s Shattering the Christ Myth. Hannam is the only professional historian contributing to that volume.
Hannam speaks of “experience” and “immersion in a particular culture”. That is indeed the critical factor. It is that sort of background that makes unquestioned assumptions so hard to identify and pull out for serious examination.
As for “cultural immersion” being a solid basis for identifying an anomalous argument, Hannam is clearly unaware of a growing number of biblical scholars (still a minority, of course) who do not consider the Jesus myth idea so “incongruous” as he suggests.
“Appeal to Confidence.” 2019. Bruce Thompson’s Fallacy Page. September 2019. https://www2.palomar.edu/users/bthompson/Appeal%20to%20Confidence.html.
Hannam, James. 2008. “A Historical Introduction to the Myth That Jesus Never Existed.” In Shattering the Christ Myth, edited by James Patrick Holding, xi–xvii. Xulon Press.