"[...] in the early days of computer science people just wrote code, then fixed bugs wherever they popped up. Knuth wanted to verify that programs worked in advance. Something is elegant, he says, if it is spare, memorable and pleasingly symmetrical; if it has the ease and immortal ring of an E=mc2. Therein lies the art in computer programming."
reading this quote some more times i really think it's partly pretty stupid; afaik in the early days of computer science compile time was breath-takingly expensive and people had to write working code deliberately; thus, they thought very hard about every line and presumably were very good in avoiding bugs beforehand. and anyway, what is the concept of a computer program "working in advance"? i hardly believe knuth has made this up...