The existence of plural and conflicting values is the central idea in the political thought of Isaiah Berlin. Berlin is often credited with the achievement of being the modern political thinker who more than any other has argued for the importance of pluralism. Bernard Williams has pointed out that Berlin has always "insisted that there exists a plurality of values which conflict with one another, and which are not reducible to one another". As a consequence "we cannot conceive of a situation in which it was true that all value-conflict had been eliminated, and that there had been no loss of value on the way". Furthermore it has to be recognized that "the business of reaffirming and defending the plurality of values is itself a political task" (Williams, 1981, p. 71).