A chart on the back of the bottle

In a supermarket in Nasr City there is an aisle of floor cleaners and kitchen sprays that promise a cleaner, safer home. The bottles have changed. They used to show a smiling mother. Now they show a graph.

The graph has a rising line, numbers with two decimal places and a technical word printed small beside the axis. Sometimes there is a cartoon germ under a magnifying glass, drawn in laboratory blue and white. No source, no sample, nothing it was compared against. Just the look of measurement.

The look works because precision feels like truth. A number with decimals sounds as if somebody counted it. A diagram sounds as if somebody checked.

Behind most of these bottles is a story. Someone used it and the house smelled cleaner. A neighbour swears by it. That is fine as far as it goes. People feel better about a room for all sorts of reasons, including the smell of something sharp on the tiles, and if the something is cheap and harmless I have no quarrel with it.

The quarrel starts when the story borrows a lab coat. The costume lets the bottle charge more. It lets someone drop the plain habits that worked, hot water and an open window, because the graph looked serious. And it does a quieter damage: the shopper who buys three of these and notices no difference begins to believe that every claim with a chart on it is noise, including the ones that were properly studied.

There is a simple test for the costume. Take the graph on its own, without the testimonial or the smiling customer, and ask what it predicts for the next person who buys the bottle. If the answer is nothing, it was never a measurement. It was a story wearing one.

Stories are allowed to be stories. They work on us anyway. They do not need to pretend to be science to earn their place on the shelf.