On the night after the Bastille fell in July 1789, Louis XVI is reported to have asked whether the news from Paris meant a revolt. "No, Sire," answered the Duke of La Rochefoucauld-Liancourt, "it is a revolution." The duke was using a word whose meaning was changing under his feet. For centuries revolution had been a term from astronomy, the title word of Copernicus's book of 1543, and it meant a circular motion that returns to its starting point, like a planet completing its orbit. When the English spoke of their "Glorious Revolution" of 1688, many of them meant something close to that older sense: a return to older liberties that a king had trampled. By the 1790s the word pointed the other way, toward a clean break with the past. Before comparing revolutions, then, it helps to be clear about what the word now covers.

Political and social revolutions

The sociologist Theda Skocpol, in a 1979 study of France, Russia and China, drew a line that most scholars still use. A political revolution changes who rules and how the state is organized, but leaves the wider society mostly in place. A social revolution goes further: it transforms class structures as well as the state, quickly, and partly through revolts from below. When peasants seize landlords' estates and a new ruling group replaces the old nobility, the change reaches into villages, workshops and families, not only into government offices. By Skocpol's strict test, social revolutions are rare. France in 1789 and Russia in 1917 qualify; many famous uprisings do not.

A broader definition

Other scholars think the strict test leaves out too much. The political scientist Jack Goldstone offers a wider definition: a revolution is an effort to transform political institutions and the claims that justify authority, carried out through mass mobilization outside normal institutions, such as street protests, strikes and general refusal to obey. This version counts movements that topple a government without remaking the economy, and it counts unarmed movements alongside armed ones. That matters for this course, because some of the most consequential transfers of power since 1945 involved almost no shooting at all.

Revolution's neighbors

Several nearby words are often confused with revolution. A coup is carried out by a small group inside the state, usually army officers, who seize the top offices without mobilizing the public; the rest of the system may stay untouched. A rebellion or revolt is an uprising that may aim only to remove a hated official or tax, not to replace the whole order. A civil war is sustained armed conflict between organized sides within one country, which can follow a revolution or replace one. Reform, finally, changes things through existing rules and offices: a parliament passes a law, a court strikes one down, voters replace a government. Reform can be sweeping, and revolution can be shallow, so the difference lies in the route, not the size of the change.

Situations and outcomes

The historian Charles Tilly, in European Revolutions, 1492 to 1992, added a distinction that keeps comparisons honest. A revolutionary situation exists when there are rival blocs, each claiming to be the government, and each commanding the obedience of a real share of the population. Tilly called this "multiple sovereignty." A revolutionary outcome is something else: power passing to a new ruling coalition. A situation can arise and then be crushed, as when foreign tanks or loyal troops restore the old rulers, and an outcome can occur without a long situation, as when a regime collapses in days. Keeping the two apart helps us see that the crowds in the square and the people who end up holding power are not always the same people.

These distinctions are not hair-splitting. A citizen who calls every protest a revolution, or every revolution a triumph, will misread events. A citizen who can ask "Who is claiming authority? Who is mobilized? What actually changed hands?" can follow a crisis as it unfolds.

Worked example: sorting four upheavals

Take four events often called revolutions. In Chile in September 1973, the armed forces bombed the presidential palace and took power. Civilians cheered and mourned, but the decisive act came from inside the state, with no mass mobilization deciding the result: a coup. In France after 1789, peasants burned manor records, nobles lost their legal privileges, the Church lost its lands and the monarchy fell: a social revolution by any test.

Egypt in 2011 is harder. Eighteen days of mass protest forced Hosni Mubarak to resign in February, and for those days there was a revolutionary situation, with Tahrir Square acting almost as a rival seat of authority. But power passed to the military high command, not to the protesters. An elected president followed in 2012, and the army removed him in 2013. By Goldstone's definition this was a revolution; by Tilly's, the outcome was thin. Czechoslovakia in late 1989 shows the opposite pattern: weeks of peaceful mass protest led to a new government, free elections and, over the next years, a new economic order. Its outcome ran deeper than its gentle methods suggested. Sorting cases this way is the first step toward asking why some upheavals build and others destroy.