Bad Ideas

Discussing bad ideas may seem like a departure from our subject of Good and Evil. Unlike a one-off bad decision such as running a stop sign, some simple or well-intentioned bad ideas become embedded in cultural, religious, or political ideologies.

The world abounds in these bad ideas. To our collective good fortune, most of them wither into obscurity, never rising to the level of producing true evil. Many are discarded over centuries of gradual reform. A few, however, have survived and continue to wreak poverty and misery, even death and destruction, on our species.

Four Historically Bad Ideas

• Religious Intolerance and Fanaticism: The notion that one’s faith is superior and must be imposed or defended through violence has sparked numerous holy wars and persecutions. Examples include the Crusades (11th–13th centuries, millions of dead), the European Wars of Religion (e.g., Thirty Years’ War, 1618–1648, up to 8 million deaths), and inquisitions like the Spanish Inquisition (1478–1834, thousands executed). These ideas persist in modern sectarian conflicts, leading to ongoing deaths. Islamic fundamentalism arose from early calls for strict scripturalism (Kharijites), developed through medieval thinkers like Ibn Taymiyya, and crystallized in modern movements such as Wahhabism, the Muslim Brotherhood, and Hamas. This is a claimed lineage of ideas, not an unbroken institution. It draws on Qur’anic verses and Hadith emphasizing divine law, struggle (jihad), Sharia governance, and often justifying armed struggle and Islamic terrorism. One strangely persistent idea is the antisemitic trope of the blood libel, a false accusation that Jewish people kidnap and murder non-Jewish children to use their blood for religious rituals. It has existed as a distinct, structured narrative for nearly 900 years, dating back to the 12th century.

• Nationalism and Ethnic Superiority: The belief in the supremacy of one’s nation or ethnic group, often tied to expansionism, has driven wars by dehumanizing “others.” This underpinned World War I (1914–1918, 20 million deaths) through aggressive alliances and imperial rivalries, World War II (1939–1945, 70–85 million deaths) via Nazi Aryan supremacy and Japanese imperialism, and ethnic cleansing like the Rwandan Genocide (1994, 800,000 deaths). It continues in modern ethnic conflicts.

• Imperialism and Colonial Exploitation: The ideology that stronger powers have a right to conquer and exploit weaker ones for resources or “civilizing” missions has caused centuries of wars and genocides. This includes European colonialism, the scramble for Africa, and earlier empires like the Mongol conquests. It echoes in neocolonial conflicts today.

• Slavery: The institutionalized ownership and exploitation of people, often hereditary and brutal, has underpinned economies and societies for millennia, sparking slave revolts, civil wars (e.g., U.S. Civil War, 1861–1865, ~750,000 deaths), and international conflicts over abolition or trade routes. Slavery has intersected with and amplified the harms of the previous three bad ideas, often serving as a tool or justification for them. These connections are evident in historical records, where slavery reinforced divisions and motivated violence. Despite universal condemnation, slavery still persists in many parts of the world.

Modern Bad Ideas

While the religious bad ideas continue, humans regularly create new bad ideas. Many are driven by carelessness, thoughtless greed, or calculated profit motives.

The following chart lists selected industrial accidents and ongoing human-caused harms, without assigning blame. It includes sudden disasters as well as slower harms from pollution, toxic exposure, and the misuse of chemicals and drugs.

While the estimated human death toll is small in some cases, it is impossible to estimate the billions of other life-forms directly killed or killed through loss of habitat caused by these events and practices.

Notes: Annual vs. single-event figures are not directly comparable but are ordered strictly by the numeric estimates shown. Ranges reflect variation across authoritative sources. * “Anthropogenic climate change” is a WHO projection, not observed current mortality. NASA says, “There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.”