Even if some departments seem to have reduced the philosophical enterprise to it, usually to avoid inter-departmental debate and to adopt a liberal/PC/or relativist attitude towards what thinkers actually hold. As I have written
before, inquiring into reality is not the same as doing intellectual history, even if intellectual history may be a useful way to gather the opinions of others. But in the end, one must still evalute those opinions and judge them by what one knows of reality.
Also, what philosophers sometimes forget is that arguments about the origins of ideas need to be framed (and evaluated) not as philosophical arguments but as historical arguments. I was thinking about this yesterday as I was reading through Kirkpatrick Sale's The Human Scale--he does not put forth any genealogy, but I could see some enthusistic undergraduate or even graduate student jump in and say, "The desire to dominate nature has its origins in Descartes" or Francis Bacon. But is it not part of the fallen human condition to assume a wrongful dominion over creation, making it serve man's disordered appetites and without any regard for the consequences or the future? It is one thing to say that the writings of Descartes or Bacon reflects this disordered desire; it's another to say that they are the intellectual progenitors of this desire, which could be named some appropriate '-ism'.
Too often philosophers try to establish their intellectual credibility by looking for the origin of ideas and locating it in some supposed focal figure in the past. While the texts may show that the author did indeed share such ideas, this is not conclusive in itself--what must be done is to show that the ideas were desseminated through him, and had an impact on society at large. This is rarely done, and usually cannot be done.
On the other hand, perhaps some notiosn of rights can be traced back in history to certain people, but the introductory texts that I have read so far have not persuaded me of this--precisely because they have not discussed the educational system of the time--what books were being read and studied in universities and law schools, and what was being cited in other texts, and so on.
At this point in time I think that
ius as a subjective active right can be found not inly during the medieval period, but before, in Roman law. But this does not mean all medievals or all Romans held to a conception of right as a manifestation of dominion or property. For the medievals at least it seems clear that there were several theories of subjective active rights, not just one.
It is better to look at the purpose that subjective active rights served within law, and to draw up an undnerstanding of rights based on that, rather than creating an
a priori theory about what rights are (within ethics or politics), and then reading this into legal texts.