Here.
Mostly, he wants to rescue atheism from relativism: “If there’s no God, everything is permitted.” For this purpose, he posits morality as “an undeveloped branch of science.” The view that science should play a key role in deciding morality and law is not unique; it surfaced as early as 1911. In an editorial, Scientific American excoriated “The absurdity of legislation to cure social evils without scientific facts to base that legislation upon.” More on the earlier absurdity later.
Harris’s project starts with the following basic assumptions: “… science should one day be able to make very precise claims about which of our behaviors and uses of attention are morally good, which are neutral, and which are worth abandoning.”