Pluralism frequently relies on the concept of incommensurability, which describes a situation in which two or more goods, values, or phenomena have no standard of evaluation that applies to them all. You can compare the size of one object in feet and another object in centimeters by converting feet to centimeters. But you cannot compare the speed of a running cheetah to the size of the Taj Mahal because one involves measuring miles per hour and the other involves measuring square feet.
Similarly, some values are simply too different to be evaluated in the same way. For example, there are some things in life that you cherish and cannot describe in terms of a dollar amount, such as love or friendship. The value of friendship is not commensurate with the value of money. Furthermore, physical health and supportive friends are both valuable, but they are good in different ways, so they are incomparable values. Even if you can evaluate values in the same way, you might not be able to compare them in the sense of judging what is better or worse than the other. For example, you might have many friendships that you value highly but not be able to rank them or determine who your best friend is.
The content of this course has been taken from the free Philosophy textbook by Openstax