Ever since the rise of modern science, an almost impregnable wall separating it from religion, morality and human values has been raised to the heights. The “naturalistic fallacy,” sometimes rendered as the “is-ought problem”—the way something “is” does not mean that is the way it “ought” to be—has for centuries been piously parroted from its leading proponents, philosophers David Hume and G. E. Moore, as if pronouncing it closes the door to further scientific inquiry.

We should be skeptical of this divide. If morals and values should not be based on the way things are—reality—then on what should they be based? All moral values must ultimately be grounded in human nature, and in my book The Science of Good and Evil (Times Books, 2004), I build a scientific case for the evolutionary origins of the moral sentiments and for the ways in which science can inform moral decisions. As a species of social primates, we have evolved a deep sense of right and wrong to accentuate and reward reciprocity and cooperation and to attenuate and punish excessive selfishness and free riding. On the constitution of human nature are built the constitutions of human societies.

Grafted onto this evolutionary ethics is a new field called neuroethics, whose latest champion is the steely-eyed skeptic and cogent writer Sam Harris, a neuroscientist who in his book The Moral Landscape (Free Press, 2010) wields a sledgehammer to the is-ought wall. Harris’s is a first-principle argument, backed by copious empirical evidence woven through a tightly reasoned narrative. The first principle is the well-being of conscious creatures, from which we can build a science-based system of moral values by quantifying whether or not X increases or decreases well-being. For instance, Harris asks, Is it right or wrong to force women to dress in cloth bags and to douse their faces in acid for committing adultery? It doesn’t take rocket science—or religion, Harris astringently opines—to conclude that such “cultural values” decrease the well-being of the women so affected and thus are morally wrong.

These examples are the low-hanging fruit on the tree of the knowledge of good and evil, so it is easy for both science and religion to pluck the ripe ones and declare with confidence that such acts as, say, lying, adultery and stealing are wrong because they destroy trust in human relationships that depend on truth telling, fidelity and respect for property. It is when moral issues become weighted with political, economic and ideological baggage that the moral landscape begins to undulate.

Harris’s program of a science-based morality is a courageous one that I wholeheartedly endorse, but how do we resolve conflicts over such hotly contested issues as taxes? Harris’s moral landscape allows the possibility of many peaks and valleys—more than one right or wrong answer to moral dilemmas—so perhaps liberals, conservatives, libertarians, Tea partiers, Green partiers and others can coexist on different peaks. Live and let live I say, but what happens when the majority of residents on multiple moral peaks pass laws that force those in the minority on other peaks to help pay for their programs of social well-being for everyone? More scientific data are unlikely to eliminate the conflict.

I asked Harris about this potential problem. “‘Live and let live’ is often a wise strategy for minimizing human conflict,” he agreed. “But it only applies when the stakes are not very high or when the likely consequences of our behavior are unclear. To say that ‘more scientific data are unlikely to eliminate the conflict’ is simply to say that nothing will: because the only alternative is to argue without recourse to facts. I agree that we find ourselves in this situation from time to time, often on economic questions, but this says nothing about whether right answers to such questions exist.”

Agreed. Just because we cannot yet think of how science might resolve this or that moral conflict does not mean that the problem is an insoluble one. Science is the art of the soluble, and we should apply it where we can.