“You are not expected to understand this.” Those seven words, which appeared in the source code of Unix’s sixth edition in 1975, have since been reproduced by computer geeks on T-shirts, mugs, jumpers and, with the inevitability of an unloved season, tote bags. The phrase’s cultural afterlife, and the reasons it has become a rallying cry for programmers everywhere, inspire the titular essay in a new collection on the most important lines of computer code in human history, and how the assumptions and choices taken by programmers shape our world today.
“You are not expected to understand this” has sometimes been used as a commentary on the arrogance and unapproachability of computer scientists. This is somewhat unfair, given that its author, Dennis Ritchie, later explained that it “was intended as a remark in the spirit of ‘This won’t be on the exam,’ rather than as an impudent challenge”.
Unfortunately, the challenge has all too often been unconsciously seized upon as an excuse not to try and understand this. In the UK, this is the case every time someone proudly says they don’t know how a microwave works — or when the actor Simon Pegg claims that Rishi Sunak’s ambition to teach maths to all pupils in England until the age of 18 is because the prime minister wants to turn the workforce into “a drone army of data-entering robots”.