One of the main charges against atheists is that we have no basis for morality. Many early atheists like Nietzsche, Sartre, and Camus echoed the same thought. But we are now entering a new era. Sam Harris is a moral realist. So also is Richard Carrier, Link. Michael Shermer seems to be one as well who argues: "Moral principles are provisionally true—that is, they apply to most people in most cultures in most circumstances most of the time." These moral principles are based in the universality of human nature; who we are and what we want. We want to be happy, holistically happy. This is an end in and of itself that needs no further justification. As we figure out what makes us happy we should do it. It can be expressed like this: "Since humans want to be happy we should therefore do X." Here is a follow-up post on this same subject.