Massimo Pigliucci refutes Harris's claim that science can answer moral questions:
The crux of the disagreement...is embodied in the title of Harris' talk: in what sense can science answer (as opposed to inform) ethical questions? Let me take one of Harris’ examples, the (highly questionable) legality of corporal punishment of children in several US States. Harris rhetorically asks whether we really think that hitting children will improve their school performance or good behavior. But that isn’t the point at all. What if it did? What if a scientific study showed that indeed, hitting children does have a measurable effect on improving those desirable traits? Harris would then have to concede that corporal punishment is moral, but somehow I doubt he would. And I certainly wouldn’t, because my moral intuition (yes, that’s what I’m going to call it, deal with it) tells me that purposefully inflicting pain on children is wrong, regardless of whatever the empirical evidence says.
...These examples could be joined by many others making the same point: if we let empirical facts decide what is right and what is wrong, then new scientific findings may very well “demonstrate” that things like slavery, corporal punishment, repression of gays, limited freedom of women, and so on, are “better” and therefore more moral than liberal-progressive types such as Harris and myself would be ready to concede. The difference is that I wouldn’t have a problem rejecting such findings just as I don’t have a problem condemning social Darwinism and eugenics but Harris would find himself in a bind. Indeed, he seems to be making a categorical mistake: what he calls values are instead empirical facts about how to achieve human wellbeing. But why value individual human wellbeing, or the wellbeing of self-aware organisms, to begin with? Facts are irrelevant to that question.
Sam Harris continues to defend his position:
I asked whether subjecting children to “pain, violence, and public humiliation” leads to “healthy emotional development and good behavior” (i.e. does it conduce to their general wellbeing and to the wellbeing of society). If it did, well then yes, I would admit that it was moral. In fact, it would appear moral to more or less everyonejust as slitting open a child’s belly to perform an emergency appendectomy seems obviously moral to anyone who understands the purpose of this procedure. The patent immorality of corporal punishment relates to the sense that it is clearly bad for children, both in the moment and in the long run (along with the fact that it is generally the product of anger, rather than benevolence, on the part of the brute holding the paddle).