The participants in the recent debate about the moral status of Holocaust-denial (Ophelia, Norm and Jonathan - follow the links back) are actually agreed on several things: firstly, that Holocaust-denial is legally permissible in this country and others; secondly, that it ought to be legally permissible; and thirdly, that it's vile and should be combated in any way other than legal censorship.
It's very hard to see why we would think that Holocaust-denial ought to be legally permissible unless we think that there's a moral right in play, that people have a moral right to speak their minds, even if what their minds contain is false and indeed disgusting. But this is what Ophelia jibs at - given that Holocaust-denial involves lies and falsifications, why should we think we have a moral right to engage in it? How can we have a moral right to lie, falsify the evidence, play fast and loose with the truth?
This is not an unreasonable question. Lies and falsifications are generally (and certainly in the case of Holocaust-denial) morally wrong. And it does seem puzzling, even paradoxical, to say that we can have a moral right to do that which is morally wrong. Nonetheless it's true that we do: we sometimes have the moral right to act - that is, people ought not to prevent us from acting - in ways which are undoubtedly morally wrong.
Why this is the case is, I think, part of the (enormous) philosophical problem of freedom of the will. But that it is the case is incontrovertible - we find examples of it all across our lives. I have the moral right to choose for myself whom I will marry, but it would be morally wrong of me to choose my best friend's partner, thereby betraying a friendship and spreading large amounts of domestic misery around. I have the moral right to do what I please (within the law) with my own money; nonetheless it's morally wrong of me to give none of it to charity. I have the moral right to join the political party of my choice - but it's morally wrong of me to choose to join a crypto-totalitarian party whose aim is to violate our moral rights and eliminate our legal ones. And so on and so on. Sometimes it really is wrong of us to exercise the moral rights which we really do have. Morality is a complicated phenomenon, and moral rights are a particularly complicated part of it. (Eve Garrard)