Incompatibility,Incommensurability, and Rationality in Value Pluralism: Isaiah Berlin’s Case

Isaiah Berlin’s idea of value pluralism has been extensively discussed in recent decades. However, there is still much controversy about the actual meaning and implication of the terms “incompatibility” and “incommensurability” when applied to values. This article analyses the Berlinian concept of value pluralism from a theoretical point of view and argues that, following Berlin’s work, incompatibility should be defined as the impossibility of two ends being combined at a maximum level―though it is possible to find compromises between them when not pursued to their maximum―whereas incommensurability refers to the existence of more than one valid, rational solution to a conflict of ends. After commenting on the arguments advanced by other scholars, the presence of a certain idea of rationality in Berlin’s notion of value pluralism is advanced. Finally, it is demonstrated that incompatibility and incommensurability provide Berlin’s pluralism with its characteristic tragic feature which differentiates it from monism.