Local councils, we learned this week, are now using “algorithms” to try to predict which children might be at risk. In popular rhetoric, algorithms are scary artificial intelligence mini-brains, the newfangled way to say that computers will take over the world. But what exactly are they?

The word sounds hi-tech, but in fact it’s very old: imported into English, via French and Latin, from the name of the ninth-century Arab mathematician al-Khwarizmi. Originally algorithm simply meant what is now called the “Arabic” system of numbers (including zero). Only later did it acquire the more specific sense in mathematics of a procedure or set of rules: a writer in 1811 called for an algorithm for establishing theorems.

To this day, algorithm is still just a fancy name for a set of rules. If this, then that; if that is true, then do this. In finance, especially, the word is often shortened to “algo”, which via “algae” evokes a sense of inexorable biological growth. But perhaps if we thought of algorithms as mere humdrum flowcharts, drawn up by humans, we’d be better able to see where responsibility really lies if, or when, they go wrong.