 Berlin does sometimes offer more starkly dramatic accounts of incommensurability, which make it hard to rule out the more radical interpretation of the concept, according to which incommensurability is more or less synonymous with incomparability. This interpretation states that values cannot be compared at all, since there is no ‘common currency’ in terms of which to compare them: each value, being sui generis, cannot be judged in relation to any other value, because there is nothing in relation to which both can be judged or measured. As a result, choices among values cannot be based on (objectively valid) evaluative comparisons, but only on personal preference, or on an act of radical, arbitrary choice, which Berlin sometimes calls ‘plumping’. But plumping need not be a disembodied, inexplicable act: it can draw, albeit subconsciously, on a hinterland of moral understanding rooted in the moral experience of the plumper and in his cultural tradition.