I couldn't see what I was to look at. Then I saw my first skein of geese and heard their call. Programs are thrown out into the harsh environment, and the bad ones die. The good ones adapt rapidly and become very robust in short order. The only problem with the metaphor is that the process isn't random at all.
Free software is artificial life, but better.
The brain thinks not by adding two and two to make four, but like a sheet of wet paper on which drops of watercolour paints are being splashed, merging into unforeseen configurations. A book reads the better which is our own, and has been so long known to us, that we know the topography of its blots, and dog's ears, and can trace the dirt in it to having read it at tea with buttered muffins. We have found to our horror that computer programs live on for decades, long after the machines and compilers that caused their misshape have died. We thus live in the purgatory created by our hackerish enthusiasm. We must force ourselves to break out of this cycle by writing excellent programs, and then molding compilers and machines to make these programs efficient, rather than vice versa.