Key Differences
Communism: A revolutionary ideology aiming for a classless, stateless society where all property is communally owned. Means of production are controlled collectively, eliminating private ownership. Historically implemented via one-party states (e.g., Soviet Union, Maoist China), often leading to authoritarianism. Goal: "From each according to ability, to each according to need."
Socialism: Broader than communism, advocating collective or state ownership of production to reduce inequality. Can be democratic (e.g., worker cooperatives) or authoritarian. Differs from communism in allowing transitional states with some private enterprise; pure communism sees the state "wither away." Think Nordic models or Venezuela's experiments.
Social Democracy: A reformist approach within capitalism, using democratic elections to expand welfare states, regulate markets, and redistribute wealth (e.g., universal healthcare, strong unions in Sweden, Denmark). Retains private ownership but tempers inequality via taxes/progressivism. Evolved from socialism but rejects revolution; influenced by Keynesianism and post-WWII consensus.
In Between:
- Democratic Socialism: Bridges socialism and social democracy—supports public ownership in key sectors (e.g., utilities) while keeping markets and elections (e.g., Bernie Sanders' policies).
- Market Socialism: Mixes markets with worker/social ownership, avoiding full state control.
- Spectrum: Communism (radical left) → Socialism (collective focus) → Democratic Socialism (elections + ownership) → Social Democracy (capitalist welfare).
For deeper reading: Wikipedia on Social Democracy notes its shift from Marxist roots to pragmatic reforms.