In Chinese philosophy, Legalism refers to a specific doctrine first expounded by Han Feizi (Han Fei-tzu in Wade-Giles) during the Spring and Autumn period of the Eastern Zhou dynasty. Legalism was based on a conception of human nature as fundamentally wicked, and the role of the state being to force people to act justly through a rigorous system of rewards and punishments. Their name in Mandarin, fajia, translates literally as "law experts". In Western terms, Legalism is roughly comparable to the view of statecraft developed by Thomas Hobbes two millenia and change later.
Legalism held the position, fairly radical for its time, that all people, aristocrat or peasent, man or woman, were fully equal in the eyes of the law, and punishments should be doled out in keeping with the crime and its circumstances, and not the social standing of the criminals. It was also exceptional in Chinese philosophical systems of the time in rejecting an idealized view of the past; since humans were and always had been basically bad, there could be no past Golden Age.
During the Warring States period, Legalism became the state doctrine of the Kingdom of Qin, and after the young prince of Qin conquered the other six warring states, reunified China, and proclaimed himself Shihuangdi, or First Emperor, Legalism became the official doctrine of all of China. However, the Qin Dynasty collapsed within a few years of the death of Qin Shihuangdi, at least partially through the excesses of the Legalist state, which apparently included mass executions, the indiscriminate practice of conscription for forced labor, and the attempted destruction of all non-Legalist philosophical and historical texts.
Because of this, the overwhelming view of Legalism, in Western, and especially in Chinese scholarship, has been a negative one. However, most of our sources on Legalism were written during the successor Han Dynasty, who had a vested interest in painting the Qin and Legalism in the worst light possible. Recent archeological finds have brought to light actual copies of the Qin legal code, which seem significantly less severe than the Han Dynasty sources paint them to be.