If an appeal to authority is irrelevant to the point made (whether or not they are actually a valid authority) and used as dismissal, does that make it a fallacy of appeal from authority, or should it be termed something else (simply, non sequitur)?


A: If Darth is Luke's father then he is also Leia's father.
B: Have you even seen the film? I worked on the set.

Even if A hasn't seen the film, and even if B is George Lucas, it doesn't address the logic of the point A made. The reply would make more sense if it the conversation went along the lines of:

A: If Han Solo is Luke's father then he is also Leia's father.
B: Have you even seen the film? I worked on the set.

but it wouldn't address the logic (though it would add a further layer of questionable sexual morality to the film:)

Wikipedia's page on argument from authority lists a "Use in logic" section which appears to cover this, but I've been told this isn't correct. I would call it a fallacy of argument from authority, because the appeal is to authority, even if it's irrelevant. So what should this be called?


These may be a better examples that separates out the factual accuracy from the logic:

A: If Darth Vader's lightsabre hits Luke's arm, then Luke's arm will be chopped off and cauterized.
B: I took physics at uni and that can't happen.

The situation doesn't have to be factually or historically accurate to be logically accurate, so B's knowledge of physics isn't enough authority to rule on the logic of a fantasy world that may have assumptions built in to it (like lightsabres are possible, there is a thing called The Force etc)

Slightly different:

A: If Darth Vader's lightsabre hits Luke's arm, then Luke's arm will be chopped off and cauterized.
B: I was on the set, they didn't use lightsabres, it was all made up.

Again, I'd say the factual accuracy doesn't address the logical point, unless A really believes that world is real. Even then, once it's cleared up that it's fantasy, being on the set wouldn't have much authority over "the physics of the Star Wars universe" without some further qualification.

  • 1
    Seems like its an appeal to authority as well. Appeals-to-authority are in general logical non-sequiturs, no matter how applicable or not the authority is. – James Kingsbery Oct 6 '15 at 16:51
  • It's unclear to me how these pairs of statements map into logical arguments and where/how an appeal to authority plays into them. – Dave Oct 6 '15 at 19:58
  • @dave I've added to the examples, I hope it's an improvement. – iain Oct 6 '15 at 20:22

Informal fallacies don't have exact definitions --their purpose is to identify common structural deficiencies in bad arguments. It is common for more than one informal fallacy to be present in an argument.

In this case, if we focus on the "I worked on the set" portion of the reply, then that portion is in fact an appeal to authority. The speaker is establishing himself as authoritative by virtue of his personal experience with the movie. He is not addressing the substance of the other person's claim.

The aptness of the authority isn't relevant to that identification. It just needs to meet the structural requirement of substituting an assertion of authority for a valid response to the substance of the opponent's claims.

  • Isn't "I have first hand experience (because I was on the set ...)" testimonial evidence? With that reading, would this answer would imply that almost all instances of testimonial evidence are appeals to authority? – Dave Oct 6 '15 at 17:52
  • @Dave All informal fallacies draw their force from being superficially similar to good arguments. The point in this case is that being on the set has nothing to do with whether or not the implied argument (Luke and Leia are siblings, Darth is Luke's father, therefore Darth is Leia's father) is correct. There are certainly cases where both authority and eyewitness testimony are legitimately relevant, but this isn't one of them. – Chris Sunami supports Monica Oct 6 '15 at 18:39
  • Thank you, that's interesting to know, and I appreciate you taking the time to answer. – iain Oct 8 '15 at 22:17

I do not read these as appeals to authority; I read both of these as cases of testimonial evidence. B is implicitly claiming to have direct knowledge of the plot of the movie from having been present when it was made. Having been there he/she is in a position to report on what he/she saw. There are a variety of potential issues involved in testimony based beliefs (not the least of of which is the truthfulness of the claimant) but, in day to day life, many of our beliefs are based on what other people told us.

  • Thanks for answering Dave, and the link is interesting. Doesn't the second example using Han Solo show that the logic of the relationships isn't being spoken to? How would testimonial evidence work there, since B can say "It didn't happen like that" but can't say "If Han Solo was Luke's father then he wouldn't be Leia's sister" without further qualification because the logic is about the way they relate? One is about what happened factually and the other is about the rules governing the relationships. – iain Oct 6 '15 at 19:54
  • @iain I think I may not really understand your question. – Dave Oct 6 '15 at 19:58
  • The trick is finding a good example to get to the nub of it. I'll see if I can do better! – iain Oct 6 '15 at 20:10

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