Questions disappear when they seem to be answered or unanswerable. The interesting missing questions are the apparently answered ones that are not, and the apparently unanswerable ones that are.
One of life's most profound questions has been thought to be unanswerable. That question is, "Why is life so full of suffering?" Impatience with centuries of theological and philosophical speculation has led many to give up on the big question, and to ask instead only how brain mechanisms work, and why people differ in their experiences of suffering. But the larger question has an answer, an evolutionary answer. The capacities for suffering — pain, hunger, cough, anxiety, sadness, boredom and all the res — have been shaped by natural selection. They seem to be problems because they are so painful and because they are aroused only in adverse circumstances, but they are, in fact, solutions.
The illusion that they are problems is further fostered by the smoke-detector principle — selection has shaped control mechanisms that express defensive responses whenever the costs are less than the protection they provide. This is often indeed, much more often than is absolutely necessary. Thus, while the capacities for suffering are useful and generally well-regulated, most individual instances are excessive or entirely unnecessary. It has not escaped notice that this principle has profound implications for the power and limits of pharmacology to relieve human suffering.
RANDOLPH M. NESSE is Professor of Psychiatry and Director of the Evolution and Human Adaptation Program at the University of Michigan. He is the author, with George Williams, of Why We Get Sick: The New Science of Darwinian Medicine.