Russel Blackford did a couple of interviews last night about his reponse to Harris's Moral Landscape book. In clarifying/refining what he said on the radio, on his blog he said:
At the same time, both interviews provided opportunities to defend David Hume, and to point out that science cannot determine our deepest values or the totality of our values, even if we otherwise accept the Harris analysis, since that analysis presumes a value of "the well-being of conscious creatures" rather than showing how this is an empirical finding. Thus, TML leaves Hume's point about the is/ought distinction unscathed: Hume never denied that you could derive an "ought" conclusion if you include in your argument an "ought" premise, such as "we ought to value/pursue/maximise the well-being of conscious creatures". His point was that you cannot derive a conclusion containing the relation "ought" solely from premises that do not contain it, but only the relation "is". So, he said, some explanation is required as to where the "ought" relation comes from or how propositions containing it are justified.
I still think this is misguided. The idea that you cannot derive an ought conclusion if you only have is relations in the premises. Yes, given a set of circumstances (is) anything I come up with (ought) right this instant is probably clouded by my own value system which is a product of my life so far. It's likely not universal. It's quite possibly wrong. It doesn't mean that there isn't an ought or more likely many oughts that one can derive, each of which would be an acceptable action. He even touches on it a few paragraphs later.
I explained how well-being may not be just one thing but a mixture of things that we do in fact value - though some of us may weight some of these things differently from others, with no further truth as to who is "correct" to do so
If you start from assuming that we are seeking the well being of concious creatures, then it is likely that given any is situation, there are multiple oughts or a mix of oughts that can be derived. Thus "landscape". I don't think Harris is asking the world to find the one correct action in a given situation that will increase well being. Rather, he is suggesting that we should be search the landscape and finding those actions which are do promote well being and seperating them from those that don't.