In short, moral discourse is, among

In short, moral discourse is, among other things, emotive, prescriptive, and universalizable, and that gives us another fact about morality.
The two contemporary approaches to morality that are to be avoided are an emphasis on natural rights and an emphasis on procedural justice (the first of which, incidentally, besides being currently in vogue, has a long and venerable history). But I should emphasize at the outset that my objection is neither to the claim that we have rights nor to a concern that procedures should be just; my objection is to reducing morality to a matter of either rights or procedures; my concern is about the consequences of framing moral thinking and discussion in these terms.
An interest in grounding morality in certain natural rights goes back a long way in history. But to refer to ‘natural rights’ (rights given in or by nature) is inherently problematic. As we have seen, what is given in nature, what is natural, and how one determines what is natural are all highly questionable. Is co-operation natural or is competition? Is it natural for the strong to exploit the weak? Are love and caring more natural than envy and self-seeking? How are we to answer these questions, especially since at one level one might say that everything that is, is given in nature. In the second place, assuming that we agree that some attitude or behaviour is ‘natural’, how do we derive an imperative or obligation from this description of nature, how do we move from ‘is’ to ‘ought’? Where is the reasoning that allows us to conclude from the descriptive statement that in nature the strong dominate the weak that it is right that they should do so? It sounds well enough in a time of slavery, for example, to talk of man’s natural right to freedom. But, even if we believe in a principle of freedom, what does it mean to say that freedom is a natural right? As a matter of fact, it is not always given in or by nature, as witness the fact that people are being enslaved. And if it were argued that, though slavery exists, it is in some other sense unnatural, why would that lead to the conclusion that we shouldn’t engage in it, any more than the fact that our marriage customs are unnatural leads to the conclusion that we shouldn’t have them? Only if we take ‘unnatural’ to mean ‘morally wrong’ does the conclusion hold: slavery is unnatural in the sense of morally wrong, therefore it is morally wrong. But this is simply to beg the question: who says it is unnatural in this sense, and on what grounds?
All in all, while it is probably fair to say that the historical record of natural rights talk is on balance talk about moral goods that many of us would be inclined to accept, such as natural rights to freedom and happiness, it is difficult to avoid the conclusion that calling them ‘natural rights’ either begs the question or provides nothing in the way of argument to support the claim that they are morally important. In calling freedom a natural right, we are either merely asserting our view that it is morally important, or we are suggesting, without providing any supporting reason, that, because it is in some sense a feature of nature or the natural life (which very often isn’t even true), it ought to be valued. Even the view that we are born free and lose our freedom through the encroachments of the dead hand of civilization is hard to sustain. In what way are we born free? Why should we maintain that the vulnerable and dependent new-born child is more free than the accomplished adult? Why is civilization to be seen as constricting rather than enhancing our freedom?