EntityQ1324171· pop 28· linked from 31 articlesduck testSign in to savemaking sure a classifier is based on observables instead of expediency or arbitrarinessConnectionsGuatemalaCountryIndianaEntitycommunismEntityCold WarEntityFidel CastroPersonAustinEntityInternational Standard Book NumberEntityIslamic StateEntitymallardEntityDouglas AdamsEntityAnatidaeEntityWayback MachineEntityLibrary of CongressEntitySergey LavrovEntitySlavoj ŽižekEntityMarx BrothersEntityabstractionEntityMonty PythonEntityinductive reasoningEntityMonty Python and the Holy GrailEntityCategoriesEnglish-language idiomsEpistemologyHeuristicsMetaphors referring to ducksRazors (philosophy)