IN ONE OF THE CHAPELS OF Peterborough Cathedral, right now there is a panel that will shows an ass participating in a harp. One isn't going to know whether to giggle or pray. Is it a supreme expression of faith in man, to waft him to nirvana like a dumb beast? Or is that twelfth-century craftsman anticipating Rabelais, who also stripped man in order to his behind and offered him a comic conquering