 Making a similar point, Ruth Chang points out that incommensurability is often conflated with incomparability. She provides clear definitions of each: incommensurability is the lack of a common unit of value by which precise comparisons can be made. Two items are incomparable, if there is no possible relation of comparison, such as ‘better than’, or ‘as good as’ (1997, Introduction). Chang points out that incommensurability is often thought to entail incomparability, but it does not. 