The Existential Fallacy

[Jenny A]

I learned a new fallacy today.
http://www.fallacyfiles.org/existent.html
I'm going to try to put this into my own words. The existential fallacy is when a class is assumed to not be empty.

Your summary is accurate. But most of the people stating premises using this fallacy won't understand it. How about:

The ability to define a thing or things, does not cause that thing or those things to exist. Nor does defining a real thing or things cause the antithesis of that thing or things to exist.