Last week's   In our Time Radio 4 BBC weekly program on the Translation Movement should be of interest to every economic historian, and especially those interested in the role of intellectual monopoly (property) in the growth of knowledge. That is, there was none - ie no intellectual property  -  and two breathtaking renaissances with out it, one Arabic, the other European.
According to Melvyn Bragg and his 3 commentators the 9th century  translation of Greek texts on health, mathematics, philosophy, religion, and  engineering into Arabic was THE critical factor in the flowering of science and culture in the Islam world for the next several centuries  , and indirectly (through the much later translation of Arabic texts into Latin) was hugely influential in the growth of the European Renaissance. Of course we're also talking "derivative works" here, since "translation" often involved detailed commentary, elaboration and interpretation, and what the author regarded as correction, as well as   modification.
Do we have a "natural experiment" here? Two great eras of flourishing knowledge in science, philosophy, arts, trade commerce ... ie  culture ...built on, amongst other things, absence of tightly enforced national or international  exclusive rights in knowledge products ?  . As I listened to this fascinating discussion it made me think of two important costs in using and communicating knowledge, one that modifies the receiving units, the other than modifies the originating content. The first , and the largest, is the language barrier, language and literacy...overcome by education. But education in language and literacy is expensive, especially so for people already educated in one language, here Arabic, needing to learn another language, Greek, to "learn" (more)  at all. Much easier (cheaper) to transalte the original source material...which of coure involves copying. But transalating was expensive - it is a manual, labour and intellect intensive task, with wages (in current dollars) of $24k PER MONHTH (if the commentators on the program are to be believed). So with costs of training the receivers (human beings) really high and  the costs of copying and translating (recoding) really high, but NO IP costs for original copies, these societies still manage to create two Renaissances. Now in our era,  costs of modifying receivers (education in specific languages) and/or costs of copying and recoding to suit those receivers is really low, do we have a Renaissance? Well, maybe yes, maybe no. One thing for sure from this history lesson - when original copy costs are low even if reproduction costs are high, knowledge can flourish and be expanded on, changed, improved, developed, diseminated in the absence of intellectual porperty rights. And the counter factual  question is most interesting: what would have happened had a tightly enforced national and international system of copyright protection system existed "protecting" greek authors from "pirate" activities in the 9th century, and in later centuries Arabic authors from Latin transaltors? I guess it is a sign of   our times that we regard translators who don't pay as "pirates" and prosecute them as  criminals  , whereas during these two Renaissance eras transaltors who didn't pay were regarded as cultural heroes (and well paid for it) .