The Western rationalist tradition, which derives from the Greeks, is the tradition of critical discussion–of examining and testing propositions or theories by attempting to refute them. This critical rational method must not be mistaken for a method of proof, that is to say, for a method of finally establishing truth; nor is it a method which always secures agreement. Its value lies, rather, in the fact that participants in a discussion will, to some extent, change their minds, and part as wiser men.
It is often asserted that discussion is only possible between people who have a common language and accept common basic assumptions. I think that this is a mistake. All that is needed is a readiness to learn from one’s partner in the discussion, which includes a genuine wish to understand what he intends to say. If this readiness is there, the discussion will be the more fruitful the more the partners’ backgrounds differ. Thus the value of a discussion depends largely upon the variety of the competing views. Had there been no Tower of Babel, we should invent it. The liberal does not dream of a perfect consensus of opinion; he hopes only for the mutual fertilisation of opinions and the consequent growth of ideas.