Why are pain and fever considered protective responses rather than diseases?

In the field of Darwinian medicine, pain and fever are categorized as protective, adaptive responses shaped by natural selection rather than diseases themselves.1

These symptoms function as essential warning mechanisms. Pain serves to alert the body to potential or actual injury, influencing an organism to withdraw from harmful stimuli. Similarly, fever is a defensive reaction against infectious disease; the elevated body temperature helps stimulate the activity of white blood cells and can directly inhibit the growth of certain bacteria and viruses.23

The reason these responses may appear excessive or occur as "false alarms" is explained by the "smoke-detector principle." Because the cost of failing to express a necessary defense is often much higher than the cost of a false alarm, natural selection has favored sensitive mechanisms that trigger these responses even when the threat is minor. While medications can often safely block these symptoms, they remain fundamental biological defenses rather than pathological conditions.1