In a recent This Week column, Damon Linker restates a common criticism of atheism – that it cannot explain or justify self-sacrifice or other morally motivated behavior that goes against our narrow self-interest:

Atheism shouldn’t be wholly identified with the confusions of its weakest exponents any more than we should reduce religious belief to the fulminations of fundamentalists. Yet when it comes to certain issues, the quality of the arguments doesn’t much matter. The fact is that there are specific human experiences that atheism in any form simply cannot explain or account for. One of those experiences is radical sacrifice — and the feelings it elicits in us.

Think of a soldier who throws herself on a live grenade to save her comrades. Or a firefighter who enters a blaze to rescue a child knowing that he will likely perish in the effort.

Or consider Thomas S. Vander Woude, the subject of an unforgettable 2011 article by the journalist Jeffrey Goldberg. One day in September 2008, Vander Woude’s 20-year-old son Josie, who has Down syndrome, fell through a broken septic tank cover in their yard. The tank was eight feet deep and filled with sewage. After trying and failing to rescue his son by pulling on his arm from above, Vander Woude jumped into the tank, held his breath, dove under the surface of the waste, and hoisted his son onto his shoulders. Josie was rescued a few minutes later. By then his 66-year-old father was dead.

This is something that any father, atheist or believer, might do for his son. But only the believer can make sense of the deed.

Pick your favorite non-theistic theory: Rational choice and other economically based accounts hold that people act to benefit themselves in everything they do……

Other atheistic theories similarly deny the possibility of genuine altruism, reject the possibility of free will, or else, like some forms of evolutionary psychology, posit that when people sacrifice themselves for others (especially, as in the Vander Woude case, for their offspring) they do so in order to strengthen kinship ties, and in so doing maximize the spread of their genes throughout the gene pool.

This type of argument is often advanced. But it rests on a false premise: that no one could have a reason for unselfish behavior unless they believe in a deity. In reality, there is no logical contradiction between denying the existence of God, yet also believing in ethical theories such as utilitarianism, Kantianism, natural rights theory, virtue ethics, and others that require us to set aside self-interest in at least some situations. Atheists can explain unselfish behavior simply by pointing out that many people believe in ethical theories that require it, and some of those people live up to their principles. As for why such theories might become popular in the first place, there is an extensive empirical literature on that subject by social scientists, historians, and other scholars, which Linker does little to rebut.

To be sure, it might be difficult for an atheist to prove that their preferred ethical theory is true. But theists face the exact same problem. Merely believing in the existence of God does not tell us much about about what is right, or when we are morally required to sacrifice self-interest for a higher value. Much like atheists, theists have radical disagreements about these issues. In the 19th century, there was extensive conflict between those theists who believed that slavery was right and just (and could cite biblical quotations to support their position), and those who argued it was evil, and that slaveowners had a moral obligation to set aside self-interest and let their slaves go. Today, theists continue to disagree radically about a wide range of moral issues, including abortion, the death penalty, free speech, gender equality, and many others.

Linker also misconstrues economics and rational choice theory. Neither assumes that people act only to “benefit themselves.” Rather, rational choice theory (which is based on economic reasoning) posits that people try to achieve their objectives as efficiently as possible, maximizing benefits and minimizing costs; cost and benefit are measured in terms of the decisionmaker’s own values, which could be selfish, altruistic, or some combination of both. If I value X’s life more than my own and the only way to save X is to sacrifice myself, that sacrifice would be entirely rational in the sense that economists and rational choice theorists use the term.

In addition, economics and rational choice theory are descriptive, not normative. They do not assume that rational behavior is necessarily good behavior. For example, I have argued that it is rational for most voters to make little or no effort to become informed about political issues. But I also believe that ill-informed voting is unethical. I could be wrong about either or both of these points. But there is no contradiction between them.