Argumentum ad Ignotas Extraneus

I’m coining a new logical fallacy: Argumentum ad ignotas extraneus

Or in plain English: Appeal to rando

It’s sort of the inverse of appeal to authority, but the way it happens is more frustrating. It can take a few forms, but this is the most common:

  • You are having a discussion with your peers about how to solve a problem.
  • As an expert in your field, you argue a solution or point-of-view that lies somewhere outside the mainstream, but you are certain from your many years of experience that it is the best path forward.
  • Your argument is briefly considered by your peers before being outvoted by the majority and a worse path (in your opinion) is taken.
  • Some time later, one of your peers wrangles you all up again and says, “Hey, I just read some article that talks about doing {exact same thing you proposed in the earlier discussion}. Have we considered doing that? Let’s try that!” (Argumentum ad ignotas extraneus is committed here)
  • “Oh?” you say. “Who said that?”
  • “I dunno, it was some blog post linked from HN or something.”
  • Wait a minute, you think. That’s exactly what I argued. Now that some rando with unknown credentials has put it in writing somewhere, all the sudden it’s valid?

This is the essence of argumentum ad ignotas extraneus: preferring to trust the opinion of someone unknown over the argument of a known peer with high credibility.

Now that I have put a name to this phenomenon, you will start to notice it, and if your peers don’t believe you when you point it out, you can link them to this post by some rando (me)!

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