A few days ago I caught the tail end of a Radio 4 discussion on images of light and darkness in major world religions. Apparently all our faiths make heavy use of light=good, dark=bad symbolism, although there are a few interesting exceptions and 'twilight areas'. At the end of the programme, the interviewer asked his panel what they would do if they had to devise a set of symbols to act as a replacement for 'light vs dark'. Most of the speakers said that no other motifs would do the job quite as well, such was the all-pervasive cultural power of notions of 'light' and 'an absence of light'. However, one person came up with an intriguing idea. He suggested that perhaps 'sound vs silence' would work quite effectively too, although he failed to point out which of the two would be seen as being superior to and more desirable than the other: 'sound' or 'the absence of sound'... or should that be 'silence' or 'the absence of silence'?