Anyone who watches the busy, tremendously productive world of Internet open-source software for a while is bound to notice an interesting contradiction between what open-source hackers say they believe and the way they actually behave—between the official ideology of the open-source culture and its actual practice. Cultures are adaptive machines. The open-source culture is a response to an identifiable set of drives and pressures. As usual, the culture's adaptation to its circumstances manifests both as conscious ideology and as implicit, unconscious or semi-conscious knowledge. And, as is not uncommon, the unconscious adaptations are partly at odds with the conscious ideology. In this essay, I will dig around the roots of that contradiction, and use it to discover those drives and pressures. I will deduce some interesting things about the hacker culture and its customs. I will conclude by suggesting ways in which the culture's implicit knowledge can be leveraged better.