Algorithms are everywhere. They play the stockmarket, decide whether you can have a mortgage and may one day drive your car for you. They search the internet when commanded, stick carefully chosen advertisements into the sites you visit and decide what prices to show you in online shops. (…) But what exactly are algorithms, and what makes them so powerful?
An algorithm is, essentially, a brainless way of doing clever things. It is a set of precise steps that need no great mental effort to follow but which, if obeyed exactly and mechanically, will lead to some desirable outcome. Long division and column addition are examples that everyone is familiar with — if you follow the procedure, you are guaranteed to get the right answer. So is the strategy, rediscovered thousands of times every year by schoolchildren bored with learning mathematical algorithms, for playing a perfect game of noughts and crosses. The brainlessness is key: each step should be as simple and as free from ambiguity as possible. Cooking recipes and driving directions are algorithms of a sort. But instructions like “stew the meat until tender” or “it’s a few miles down the road” are too vague to follow without at least some interpretation.
The Economist, August 30, 2017.