Richard Marshall interviews Torbjörn Tännsjö in 3:AM Magazine:
3:AM: Why are you a moral realist and what difference does this make to how you go about investigating morals from, for example, a non-realist?
TT: I am indeed a moral realist. In particular, I believe that one basic question, what we ought to do, period (the moral question), is a genuine one. There exists a true answer to it, which is independent of our thought and conceptualisation. My main argument in defence of the position is this. It is true (independently of our conceptualisation) that it is wrong to inflict pain on a sentient creature for no reason (she doesn’t deserve it, I haven’t promised to do it, it is not helpful to this creature or to anyone else if I do it, and so forth). But if this is a truth, existing independently of our conceptualisation, then at least one moral fact (this one) exists and moral realism is true. We have to accept this, I submit, unless we can find strong reasons to think otherwise. Moral nihilism comes with a price we can now see. It implies that it is not wrong (independently of our conceptualisation) to do what I describe above; this does not mean that it is all right to do it either, of course, but yet, for all this, I find this implication from nihilism hard to digest. It is not difficult to accept for moral reasons. If it is false both that it is wrong to perform this action and that it is right to perform it, then we need to engage in difficult issues in deontic logic as well. So we should not accept moral nihilism unless we find strong arguments to do so. So are there any good arguments in defence of moral nihilism? I think not and I try to defend this claim in my From Reasons to Norms. On the Basic Question in Ethics (2010). It is of note that for a long time moral nihilism was a kind of unquestioned default position in analytic moral philosophy. What initiated the interest in moral realism was the fact that, in 1977, two authors, John Mackie and Gilbert Harman, independently of one another, put forward arguments in defence of the nihilist position. This triggered an interest in what had up to then been a non-issue. When thinking carefully about their arguments for nihilism I didn’t find them convincing. I was not alone. At first there was a trend towards moral realism in its “Cornell”, i.e naturalist, style. In my book Moral Realism (1990) I didn’t take a stand on the naturalist/non-naturalist issue. I am now a decided non-naturalist realist. And today we may even speak of a trend towards non-naturalist moral realism (for example Derek Parfit, David Enoch, apart from myself).
Being a moral realist I see normative ethics as a search of the truth about our obligations and a search of explanation; the idea is that moral principles can help us to a moral explanation of our particular obligations.
More here.