Left-wing politics supports social equality and egalitarianism, often in opposition of social hierarchy. Left-wing politics typically involves a concern for those in society whom its adherents perceive as disadvantaged relative to others as well as a belief that there are unjustified inequalities that need to be reduced or abolished. According to emeritus professor of economics Barry Clark, left-wing supporters “claim that human development flourishes when individuals engage in cooperative, mutually respectful relations that can thrive only when excessive differences in status, power, and wealth are eliminated.

Within the left–right political spectrum, Left and Right were coined during the French Revolution, referring to the seating arrangement in the French Estates General. Those who sat on the left generally opposed the Ancien Régime and the Bourbon monarchy and supported the French Revolution, the creation of a democratic republic and the secularisation of society while those on the right were supportive of the traditional institutions of the Old Regime. Usage of the term Left became more prominent after the restoration of the French monarchy in 1815, when it was applied to the Independents.The word wing was first appended to Left and Right in the late 19th century, usually with disparaging intent, and left-wing was applied to those who were unorthodox in their religious or political views.

The term Left was later applied to a number of movements, especially republicanism in France during the 18th century, followed by socialism, including anarchism, communism, the labour movement, Marxism, social democracy and syndicalism in the 19th and 20th centuries.Since then, the term left-wing has been applied to a broad range of movements, including the civil rights movement, feminist movement, LGBT rights movement, anti-war movement and environmental movement as well as a wide range of political parties.

The terms “left” and “right” appeared during the French Revolution of 1789 when members of the National Assembly divided into supporters of the king to the president’s right and supporters of the revolution to his left.One deputy, the Baron de Gauville, explained: “We began to recognize each other: those who were loyal to religion and the king took up positions to the right of the chair so as to avoid the shouts, oaths, and indecencies that enjoyed free rein in the opposing camp”.

When the National Assembly was replaced in 1791 by a Legislative Assembly comprising entirely new members, the divisions continued. “Innovators” sat on the left, “moderates” gathered in the centre, while the “conscientious defenders of the constitution” found themselves sitting on the right, where the defenders of the Ancien Régime had previously gathered. When the succeeding National Convention met in 1792, the seating arrangement continued, but following the coup d’état of 2 June 1793 and the arrest of the Girondins the right side of the assembly was deserted and any remaining members who had sat there moved to the centre. However, following the Thermidorian Reaction of 1794 the members of the far-left were excluded and the method of seating was abolished. The new constitution included rules for the assembly that would “break up the party groups”.

The terms “left” and “right” were not used to refer to political ideology per se, but only to seating in the legislature. After 1848, the main opposing camps were the “democratic socialists” and the “reactionaries” who used red and white flags to identify their party affiliation. With the establishment of the Third Republic in 1871, the terms were adopted by political parties: the Republican Left, the Centre Right and the Centre Left (1871) and the Extreme Left (1876) and Radical Left (1881). The beliefs of the group called the Radical Left were actually closer to the Centre Left than the beliefs of those called the Extreme Left