It’s the second day of Christmas and my true love gave to me: an argument from authority. She claimed that she could taste sweet things on the tip of her tongue only, something a lot of us were probably taught as children, I know I was. Take a look at the tongue map.
It is complete and utter nonsense. It has been known to be complete and utter nonsense for over 40 years yet it was taught to children all over the world right into the 90s at least. Hopefully no longer.
It arose over a century ago and is based on a misunderstanding of an original text but was taken up in the textbooks. Unfortunately that’s where it remained for a very long time despite anyone being able to disprove it with their own tongue. En masse there was an appeal to the authority of the textbooks and the apparent body of knowledge that existed.
An appeal to authority, then, is the fallacy where instead of using logic or evidence to counter someone else’s evidence you appeal to an authority to automatically dismiss it out of hand. Put another way:
A says F about x
A knows a lot about x
Therefore F is true
It can also be used in the negative:
A says F about x
B says A is wrong
Therefore F is incorrect
Politicians are constantly appealing to authority. The Prime Minister says x, or such and such a report says y, therefore I’m going to screw over this particular part of the population. The wrinkle in this particular fallacy is that it is perfectly possible that the authority is, indeed, correct. If they are correct, though, it must be because they have the best evidence and/or argument, not merely because they are an authority.
An example of where the argument from authority is frequently misapplied is when some crack pot or other says that using the existing body of science is fallacious. This is not the case. The edifice of scientific knowledge is not an assertion from an individual, it is a rigorously tested, peer reviewed, tried and tested set of answers, all of which are open to correction or refinement. This isn’t to say that it cannot ever be wrong, nothing is infallible. But for a lone climate change denier or creationist to argue that using the science is simply an appeal to authority is not valid.
If multiple lines of independent evidence all converge on the same answer then you can be very confident that the broad strokes of that answer are correct and unlikely to change, perhaps the details will here and there but not the main thrust. To claim the contrary would be an extraordinary claim and as the inimitable Carl Sagan said: extraordinary claims require extraordinary evidence.