Dijkstrian Elegance

Dijkstra used the word elegance in a sense most readers misheard as aesthetic. He meant something far more severe. An elegant program is one you can look at and see why it works. An inelegant program is one that works but conceals its own logic. The first is correct for reasons that can be stated; the second is correct by accident — it works because its bugs happen not to be triggered by the inputs it has received. Elegance is therefore not a matter of taste but of epistemic status: the elegant solution is trustworthy because its correctness is demonstrable at a glance; the inelegant solution is a bet. Dijkstra's lifelong insistence on elegance was engineering judgment, not aesthetic preference. He believed — and the failure histories of complex systems have borne him out — that the only reliable code is code simple enough to be understood, and the only way to achieve such simplicity is to demand it, relentlessly, against the constant pressure of a culture that rewards output over