torpor

Torpor is Latin, from the verb torpēre, meaning to be stiff, numb, or sluggish. The word described the physical sensation of a limb gone dead — the arm that has been slept on, the foot that has lost feeling. But Latin made no clean distinction between physical and moral numbness. A torpid senator and a torpid leg were the same kind of problem. Both had stopped doing what they were supposed to do.

Pliny the Elder used torpor to describe the state of hibernating animals. The torpid hedgehog, the torpid dormouse — these creatures went rigid and cold through the winter months. This usage gave torpor its zoological meaning, which survives in modern biology: torpor is a state of decreased physiological activity, characterized by reduced body temperature and metabolic rate. Hummingbirds enter torpor nightly to survive. Bears enter a related state seasonally.

In English, torpor appeared by the fifteenth century with both its physical and moral meanings intact. Sermons warned against spiritual torpor. Physicians treated physical torpor with stimulants. The word retained its Latin ambiguity: a torpid person might need medicine or a lecture, depending on which kind of numbness afflicted them. The Enlightenment tended toward the moral usage — torpor was the enemy of progress, industry, and rational action.

Modern English uses torpor less frequently than it once did. 'Lethargy' and 'apathy' have absorbed some of its territory. But torpor names something neither of those words quite captures — not just tiredness, not just indifference, but a full-body shutdown, a system going into conservation mode. The hummingbird does it to survive the night. Humans do it to survive the things they cannot face.