Some of humanity’s most stunning achievements are scientific, and science is rightly venerated for helping people live better, longer, more varied, and fulfilling lives. Science can do a lot. In the minds of cynical opportunists, it can even be used to end an argument: “Follow the science.” “I am the science.” “The science is settled.”

Science may tell us much about how the universe works, but it is not yet very helpful in describing how human relations and politics work. Social “sciences” are often more art than science. In policymaking, science becomes just another input, one of many competing goods, drawbacks, desires, fears, and limitations. Science informs good policy, but it does not dictate it.