" 

 ::::::::Um, I've never heard anybody use the word arbitrary to mean ""authoritarian"". But even if that were the case, I don't see what's authoritarian about looking at the solar system and calling things what they are. The word  means ""Determined by impulse rather than reason; chosen for no reason or at random."" It seems to me that the new definition is determined by reason but calling Pluto a planet is just truthy for some people.  "