Sam Harris is confused .
Many Philosophers & Scientists have reject what he asserts (Look it up). He ignores the Fact-Value distinction.
https://en.wikipedia.org/wiki/Fact–value_distinction
He calls Moral values for facts. When in actuality Scientific facts can only describe how the natural world is, they do not tell you how the world ''ought to be be '' and Moral truths carries ''oughtness''
For example, In this piece,
http://www.utilitarian.net/singer/by/197301–.htm Peter Singer distinguishes between “neutralists” and “descriptivists.” Neutralists say that any principle can count as moral if it purports to be overriding (not that we have to all agree that it’s morally good in order for it to count as a moral principle).
Descriptivists, on the other hand, place restraints on what counts as a moral principle (is logically tied to suffering and happiness).
On this scale, Harris is a descriptivist, and as such, must reduce all moral disagreement to a semantic disagreement over what morality actually means, which is an incredibly impoverished way of understanding the diversity of values in the world today, if you ask me.
Intellectuals agree on that Moral truths and Scientific facts are distinct from one another. Therefore Science cannot explain Moral questions.