‘We are encouraged to imagine we understand massive conceptual change or profound contrasts by legitimate examples of a familiar sort. Sometimes an idea, like that of simultaneity as defined in relativity theory, is so important that with its addition a whole department of science takes on a new look. Sometimes revisions in the list of sentences held true in a discipline are so central that we may feel that the terms involved have changed their meanings. Languages that have evolved in distant times or places may differ extensively in their resources for dealing with one or another range of phenomena. What comes easily in one language may come hard in another, and this difference may echo significant dissimilarities in style and value. But examples like these, impressive as they occasionally are, are not so extreme but that the changes and the contrasts can be explained and described using the equipment of a single language. Whorf, wanting to demonstrate that Hopi incorporates a metaphysics so alien to ours that Hopi and English cannot, as he puts it, "be calibrated," uses English to convey the contents of sample Hopi sentences. Kuhn is brilliant at saying what things were like before the revolution using – what else? – our post-revolutionary idiom. Quine gives us a feel for the "pre-individuative phase in the evolution of our conceptual scheme," while Bergson tells us where we can go to get a view of a mountain un-distorted by one or another provincial perspective. The dominant metaphor of conceptual relativism, that of differing points of view, seems to betray an underlying paradox. Different points of view make sense, but only if there is a com-mon coordinate system on which to plot them; yet the existence of a common system belies the claim of dramatic incomparability. What we need, it seems to me, is some idea of the considerations that set the limits to conceptual contrast. There are extreme suppositions that founder on paradox or contradiction; there are modest examples we have no trouble understanding. What deter-mines where we cross from the merely strange or novel to the absurd?’