  Category mistakes are sentences such as ‘The number two is blue’, ‘The theory of relativity is eating breakfast’, or ‘Green ideas sleep furiously’. Such sentences are striking in that they are highly odd or infelicitous, and moreover infelicitous in a distinctive sort of way. For example, they seem to be infelicitous in a different way to merely trivially false sentences such as ‘\(2 + 2 = 5\)’ or obviously ungrammatical strings such as ‘The ran this’.