There is something improbably about the silence in the [subway] carriage, considering how naturally gregarious we are as a species. Still, how much kinder it is for the commuters to pretend to be absorbed in other things, rather than revealing the extent to which they are covertly evaluating, judging, condemning and desiring each other. A few venture a glance here and there, as furtively as birds pecking grain. But only if the train crashed would anyone know for sure who else had been in the carriage, what small parts of the nation's economy had been innocuously seated across the aisle just before the impact: employees of hotels, government ministries, plastic-surgery clinics, fruit nurseries and greetings-card companies.