He walked for days, stopping at bars and restaurants whenever he felt thirsty, hungry or tired; mostly they were automatic and he was served by little floating trays, though a few were staffed by real people. They seemed less like servants and more like customers who'd taken a notion to help out for a while.

'Of course I don't have to do this,' one middle-aged man said, carefully cleaning the table with a damp cloth. He put the cloth in a little pouch, sat down beside him. 'But look; this table's clean.'

He agreed that the table was clean.

'Usually,' the man said. 'I work on alien - no offence - alien religions; Directional Emphasis In Religious Observance; that's my speciality... like when temples or graves or prayers always have to face in a certain direction; that sort of thing? Well, I catalogue, evaluate, compare; I come up with theories and argue with colleagues, here and elsewhere. But... the job's never finished; always new examples, and even the old ones get re-evaluated, and new people come along with new ideas about what you thought was settled... but,' he slapped the table, 'when you clean a table you clean a table. You feel you've done something. It's an achievement.'