If N were an accurate analysis of 'good', then the question 'I know it is N but is it good?' would not be conceptually open for a competent judge

Moore’s “Open Question Argument” for the conclusion that goodness is a non-natural property is closely related to his worries about the naturalistic fallacy. Consider any proposed naturalistic analysis N of a moral predicate M. The Open Question Argument maintains that it will always be possible for someone competent with moral discourse without conceptual confusion to grant that something is N but still wonder whether it is really M. Whether goodness is co-instantiated with any natural property