The Is-Ought Fallacy of Science and Morality

Ever since the philosophers David Hume and G. E. Moore identified the “Is-Ought problem” between descriptive statements (the way something “is”) and prescriptive statements (the way something “ought to be”), most scientists have conceded the high ground of determining human values, morals, and ethics to philosophers, agreeing that science can only describe the way things are but never tell us how they ought to be. This is a mistake.

We should be worried that scientists have given up the search for determining right and wrong and which values lead to human flourishing just as the research tools for doing so are coming online through such fields as evolutionary ethics, experimental ethics, neuroethics, and related fields. The Is-Ought problem (sometimes rendered as the “naturalistic fallacy”) is itself a fallacy. Morals and values must be based on the way things are in order to establish the best conditions for human flourishing. Before we abandon the ship just as it leaves port, let’s give science a chance to steer a course toward a destination where scientists at least have a voice in the conversation on how best we should live.

We begin with the individual organism as the primary unit of biology and society because the organism is the principal target of natural selection and social evolution. Thus, the survival and flourishing of the individual organism—people in this context—is the basis of establishing values and morals, and so determining the conditions by which humans best flourish ought to be the goal of a science of morality. The constitutions of human societies ought to be built on the constitution of human nature, and science is the best tool we have for understanding our nature. For example:

  • We know from behavior genetics that 40 to 50 percent of the variance among people in temperament, personality, and many political, economic, and social preferences are inherited.
  • We know from evolutionary theory that the principle of reciprocal altruism—I’ll scratch your back if you’ll scratch mine—is universal; people do not by nature give generously unless they receive something in return.
  • We know from evolutionary psychology that the principle of moralistic punishment—I’ll punish you if you do not scratch my back after I have scratched yours—is universal; people do not long tolerate free riders who continually take but never give.