The question of what (human) rights are is a big, and a vague, one (ditto the related questions of where rights come from, and what obligations they impose, etc.). I don't know how to answer it, or begin to answer it -- partly because I don't know what sort of question it is, or what sort of thing it is a question about (personal incapacity also plays a part, of course). Here, I don't intend to address the question of rights directly. Rather, I want to ask (and only ask), what sort of claims are rights claims? Or, put differently (in a way which I hope is clarifying), when you or I make an assertion to someone having a right, what sort of statement are we making?
I can think of three ways of regarding rights-claims (or rights-statements), though I suspect that I'm missing some possibilities (and that these can be formulated better than I have done thus far).
The first is to regard rights-claims as fairly simple factual claims; by simple factual claims, I mean claims that things exist or don't exist in the world -- claims which I assume are thus empirically testable. That is to say, when I claim that X has a right to Y, I mean to assert that there is some feature -- some thing -- that X posseses, in much the same way as X posseses brown hair or two hands or the ability to speak.
Now, this seems to me a non-starter (though I may be wrong here). I don't see how rights can be regarded as 'simple' facts, since they seem not to be material objects, or easily identifiable (physical) qualities of persons. If 'X has a right to Y' is a simple factual claim, I don't understand what it means.
A second possibility is that 'X has a right to Y' is a normative claim, of a particular sort -- what one might call (if the perhaps seemingly paradoxical phrase be permitted) a claim of normative fact. That is to say, 'X has a right to Y' means 'There exists an obligation on the part of persons (in a particular relationship to X) to respect X's right to Y -- that is, to not hinder X from Y, or to help X secure Y.' This claim, in turn, rests on a 'normative reality' -- some feature of X, or of the relationship between X and Y, or the relationship between X and other agents or persons or individuals, which demands that others respect X's right to Y.
Now, this seems to me a much better description of what many people think they are doing or saying when they make rights-claims. It also, of course, leaves open, and indeed begs, a number of questions; I tend to think that its from conceiving of rights-claims in this way that many discussions of rights, and thus many of the theoretical questions commonly asked about rights, begin. I'm not sure if this is the best way to think of or use rights-claims, or if this is the way that I'd prefer to think of and use them; but I think a discussion of rights-claims should recognise that this is both a common and attractive, and also problem-raising, way of understanding rights-claims.
A third possibility is that rights-claims are not statements of facts of any sort, but rather a sort of act. On this understanding, when I say 'X has a right to Y', I am not offering a description of X or Y or the relationship between them. Rather, 'X has a right to Y' means 'I believe that you should give/allow Y to X; do so'. That at least is the basic import of the statement -- that it is an attempt to secure Y for X because we believe that X should have Y. In fact, of course, it's a somewhat more charged and complex statement -- it means not only 'Give or allow Y to X' or 'I think that X should have Y', but 'I/we think that Y is in some way or for some reason vitally important to X, and that to deny Y to X is to offend against X in some way'. So it's not just a matter of imposing what we'd rather like to see happen, for whatever reasons, through the use of morally bullying language (of course, sometimes rights claims will be just this; but they claim, and are understood, to be more). It does involve making a normative claim. But it is different from the second possibility. In that understanding of rights claims, rights are taken to be original -- that is, people have rights, and from these follow obligations, and it is because people have rights that we can claim rights for ourselves or others. In this third understanding, we begin with the belief that people should -- for whatever reason -- have certain things, and from this insist on their being granted rights to those things. That is: in option 2, we are saying that X should have Y because X has a right to Y; in option 3, we are saying that because X should have Y, X should be granted a right to Y, or should have a right to Y recognised. On the third understanding of rights claims, rights don't actually explain anything; rather, they are ways of calling for the recognition and instantiation of things that need to be explained in other ways -- or ways of conferring a particular sort of status on certain goals. To say that I have a right to free speech doesn't actually explain why I should be allowed to say what I like; it merely asserts that I should be allowed to say what I like -- and that my being allowed to do so is particularly important. For an explanation we need recourse to some other theory, or normative premise, which will convince us that the right -- and the actualisation of the right (that is, my ability to say what I like being respected by others) -- are justified or demanded.
I said at the beginning that I was going to talk about what sort of claims rights-claims are, rather than what sort of things rights are; but clearly the two aren't so separable, and I've thus been doing both. On the first conception of rights-claims, rights are simple facts about people -- properties of persons that are no more complex than any physical or psychological properties that we commonly recognise. This is a conception of rights that I find hopelessly obscure and impossible to adopt. On the second conception of rights-claims, rights are still features of or facts about people, but of a more complicated (and definitely not physical) they are things that people possess, that demand that people be treated in particular ways. On the third conception of rights-claims, rights are particular conditions that we think should prevail -- abilities or protections that we claim on behalf of some people in relation to others, or certain obligations that we insist people recognise in relation to others, for reasons that the rights-claims themselves don't specify.
In the first understanding of rights claims, I have no difficulty understanding what sorts of things rights are supposed to be -- but I find it difficult to understand how rights can be these things, or how such things can be found to exist. In the second understanding, I have no difficulty seeing how rights can be the sorts of things that they are claimed to be; but I find the sort of thing itself obscure (as reflected in my rather confused explanation of it). The third understanding seems to me less obscure, but it does leave a good deal unanswered; and in particular, it merely states, but cannot explain, the special status that rights have for us -- the way in which they act as 'trumps' or 'side constraints'.
So I'm not wholly satisfied with any of these ways of understanding rights-claims -- or with my own formulation of them; nor do I think that this exhausts the possibilities -- it merely exhausts my own capacities. So I'd welcome any suggestions about other ways to understand rights claims, or better ways to formulate and analyse the understandings I've suggested.