Abstract

When our oldest daughter, Sarah, was four years old the family kitten, Fluffy, contracted fleas. There ensued a primitive ritual of flea extermination that touched off the following discussion:Sarah: ‘Daddy, how did Fluffy get fleas?’Me: ‘Oh, I suspect she was playing with a cat that already had fleas. The fleas on that cat jumped off on to Fluffy.’Sarah : ‘And how did that cat get fleas?’Me : ‘Oh, probably from another cat.’Sarah : ‘But, Daddy, it can't go on and on like that forever. The only thing that goes on and on like that forever is numbers.’