For millennia, philosophers have argued over why humans sleep and dream. In his fourth-century-bc treatise⁽²⁾ On Sleep and Sleeplessness, the philosopher Aristotle argued that sleep is a necessary, natural suspension of consciousness that allows the body and soul to recover.
数千年来，哲学家们一直争论人类睡眠与做梦的缘由。公元前四世纪，哲学家亚里士多德在其论著《论睡眠与失眠》中提出，睡眠是意识必要且自然的暂停状态，能让身心得以修复。
This view fell out of fashion during the Age of Enlightenment in the late seventeenth century. The philosophers John Locke and David Hume, for example, thought that sleep hindered⁽³⁾ rationalism and the pursuit of knowledge. Hume lumped sleep together with fever and madness as an impediment⁽⁴⁾ to rational thought. Locke saw sleep as a regrettable, if unavoidable, disruption of God’s desire for humankind to be rational and industrious. The essayist Jonathan Crary put this view more succinctly⁽⁵⁾ — “sleeping is for losers” — when he wrote about how sleep is often devalued⁽⁶⁾ in modern society.
这一观点在 17 世纪末启蒙运动时期不再流行。例如，哲学家约翰・洛克与大卫・休谟认为，睡眠阻碍理性主义与知识探索。休谟将睡眠与发烧、精神错乱归为一类，视作理性思考的障碍。洛克认为，睡眠虽无法避免，却令人遗憾地打破了上帝期许人类理性勤勉的本意。散文家乔纳森・克拉里在论述现代社会睡眠常被贬低的现状时，将这一观点精辟概括为：“弱者才贪睡”。
Modern science, meanwhile, has increasingly come to echo⁽⁷⁾ Aristotle. It provides a chorus of evidence about the importance of sleep for a host of crucial functions, including cognition⁽⁸⁾, emotional regulation, immunity, metabolism and social bonding. Sleep is essential for cleansing the brain of metabolic waste, trimming synapses and maximizing the efficiency of cognitive processing.
与此同时，现代科学愈发认同亚里士多德的观点。大量证据表明，睡眠对认知、情绪调节、免疫、新陈代谢及社会联结等诸多关键机能至关重要。睡眠能清除大脑代谢废物、精简突触连接，并最大化认知处理的效率。
Enter David Samson, a biological anthropologist at the University of Toronto in Canada, asking a provocative question: why, if sleep has so many benefits, do humans as a species sleep so little?
加拿大多伦多大学生物人类学家戴维・萨姆森提出了一个发人深省的问题：既然睡眠益处良多，人类作为一个物种为何睡眠时间却很短？
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