The other day I had a discussion over a cup of coffee which helped me clarify my ideas on human rights (and perhaps on philosophy also). I am coming to the view that rights are a way of speaking rather than something one can have a theory about. [I am not talking of legal rights* here, but rather about what might be called moral or natural rights (sometimes seen as the basis or justification for legal rights).]
My interlocutor was particularly interested in whether or not children have rights. We agreed that animals do not, because they could never comprehend the reciprocal notion of obligation. But nor can very young children. I suggested that maybe children could be granted rights on the basis that they would grow in the future to understand reciprocal obligations.
My friend noted that respect for children was built into the moral convention that (women and) children are given priority in the sinking ship scenario, but I suggested that it was not useful to talk about this in terms of rights. He said that adults giving themselves priority over (weaker) children in life-or-death situations - pushing children aside in the rush for the lifeboats - was considered morally despicable. True. But I don't think 'rights' are necessarily involved here - certainly the situation can be fully described without using the word.
When I imagined a pregnant woman with a terminal brain tumor on the sinking ship (to highlight the question of the status of the unborn child in this situation), I began to recognize the absurdity into which these sorts of discussion all too often descend.
All this strengthened my conviction that rights (and similar concepts) cannot be treated scientifically, as it were. They cannot be quantified or dealt with in a scientifically precise way. As with many other issues of semantics and communication, there are prototypical cases, where a concept is fairly clear, and more marginal cases, where there is scope for disagreement.
To take a trivial but instructive case, if I am queueing in a supermarket and somebody tries to push in ahead of me, I can justly tell him that he has no right to do so. (Either he has failed to understand the queueing convention or he is flouting it.)
Too often, though, the concept of rights is used in contexts far removed from these semantically clear cases, and far removed also from any spontaneous and plausible natural language usage. Such tendentious and problematic use of the term only serves to sow confusion.
'Right' and 'rights' are just words, but words which, used sparingly and appropriately, evoke an aspect of the multifaceted moral environment in which we all move.
*Explicit laws (or rules or regulations) can of course unambiguously assign legal (or other formal) rights to individuals or groups.