Z:gnu-www-ja-stallman-kth--130bf3-The third level of harm is in/en

The third level of harm is in the interaction between software developers themselves. Because any field of knowledge advance most when people can build on the work of others, but ownership of information is explicitly designed to prevent anyone else to doing that. If people could build on other people's work, then the ownership would become unclear, so they make sure each new entry to the field has to start from the beginning, and thus they greatly slow down the advance of the field.