"...So in answer to the current question I am proposing that we now change the usage of the word Aether, using the old spelling, since there is no need for a term that refers to something that does not exist. Instead, I suggest we use that term to describe the role of any free parameter used in a similar way: that is, Aether is the thing that makes my theory work....
"Often Aetherists (theorists who rely on an Aether variable) think that their use of the Aether concept renders the theory untestable. This belief is often justified during their lifetimes, but then along comes clever empiricists such as Michelson and Morley and last year's tautology become this year's example of a wrong theory.
"Aether variables are extremely common in my own field of economics...."
Matthew Yglesias says he prefers "phlogiston".
(h/t Robert Vienneau at Thoughts on Economics)