The other day, my discussion with Oscar about vague essential properties (see the Comments section to his "RG Modality"-post turned into a nice beer-fuelled evening of talk, laughter and goodnatured name-calling. The topic soon expanded to the venerable question whether there are essential properties at all, with a bunch of people split quite nicely over the issue. Oscar was joined by Manolo M. on the "of course there are" front, while I was joined by Sanna on the side that was soon called "the Postmodernists", which I still find very amusing. Jose C., Pepe and Guido took up various positions in the middle, and off we were.
I won't try to record the whole thing, but here's a taste of the strange arguments that were produced (that's the nice thing about writing a post, by the time the others get to quote the strange arguments you yourself came up with after your third beer, they're already in the relatively obscure Comments section...):
In the case of the discussion whether Pluto and Sedna (or how that thing was called) were planets, what was at stake was to find a definition that captures the essential property "to be a planet". That is to say, either it was (at that time) objectively false to call Pluto a planet five years ago, or it is objectively false to deny that Pluto is a planet today.
If you find that bizarre, it might be because you're a postmodernist as well, or, as Oscar later suggested, a postmodalist.